Exposure based intervention compared to stimulus control

as a treatment for Hair-pulling disorder and Skin-picking

disorder

A clinical controlled trial

Lárus Valur Kristjánsson

Lokaverkefni til cand. psych.-gráðu

Sálfræðideild

Heilbrigðisvísindasvið

Berskjöldunarmiðað inngrip samanborið við áreitastjórnun sem meðferð

við Hárreyti- og Húðkroppunaráráttu

Lárus Valur Kristjánsson

Lokaverkefni til cand. psych. gráðu

Leiðbeinendur: Ragnar Pétur Ólafsson og Ívar Snorrason

Sálfræðideild

Heilbrigðisvísindasvið Háskóla Íslands

Júní 2017

Exposure based intervention compared to stimulus control as a treatment

for Hair-pulling disorder and Skin-picking disorder

Lárus Valur Kristjánsson

Thesis for the degree of Cand. Psych.

Supervisors: Ragnar Pétur Ólafsson og Ívar Snorrason

Department of Psychology

School of Health Sciences

June 2017

Ritgerð þessi er lokaverkefni til cand. psych. gráðu í sálfræði og er óheimilt að afrita ritgerðina nema með leyfi rétthafa.

© Lárus Valur Kristjánsson 2017

Prentun: Háskólaprent, 2017

Reykjavík, Ísland 2007

3

Útdráttur

Markmið: Hárreyti- (Hair-pulling disorder; HPD) og húðkroppunarröskun (Skin-picking

disorder; SPD) eru tiltölulega algengar raskanir sem geta orðið að langvarandi vanda ef

viðeigandi meðferð er ekki veitt. Algengasta meðferðin sem einstaklingar með þessar

raskanir fá er serótónínvirk lyfjameðferð sem oft sýnir lítinn sem engan árangur. Meðferð við

þessum röskunum er lítið rannsökuð og vöntun er á gagnreyndum meðferðarinngripum.

Markmið rannsóknar var að athuga árangur vísbenda-berskjöldunar með svarhömlun (e. cue-

exposure with response prevention; CERP) sem meðferðarinngrip við HPD og SPD. Habit

reversal þjálfun (e. Habit Reversal Training; HRT) ásamt CERP var því borin saman við

HRT með áreitastjórnun (e. stimulus control; SC) sem er kjörmeðferð við þessum kvillum.

Aðferð: Þátttakendur voru 20 háskólanemar sem uppfylltu greiningarskilmerki fyrir annað

hvort HPD (n=5) eða SPD (n=15). Þeim var raðað í meðferðarinngripin af handahófi. Allir

þátttakendur fengu fjórar meðferðastundir þar sem tíu fengu HRT-CERP og tíu fengu HRT-

SC. Þátttakendur mættu einnig í upplýsingaviðtal bæði fyrir og eftir meðferðarinngrip auk

eftirfylgdarviðtals í gegnum síma einum mánuði síðar.

Niðurstöður: Niðurstöður sýndu að það dróg verulega úr alvarleika einkenna í kjölfar

meðferðar í báðum hópunum. Munur á meðferðarhópum var ekki marktækur þegar árangur

var metinn með sjálfsmatskvörðum en reyndist marktækur þegar árangur var metinn í

viðtölum og var HRT-CERP þá árangursríkari. Áhrifastærðir (Cohen‘s d) voru ívið hærri í

HRT-CERP hópnum (2.27-2.96) samanborið við HRT-SC (1.28-1.30) á öllum mælitækjum.

Ályktanir: Niðurstöður þessarar rannsóknar benda til að HRT-CERP sé áhrifaríkt

meðferðarinngrip við hárreyti- og húðkroppunarröskun, sem ætti að þróa frekar. Mikilvægt er

meðal annars að meta árangur meðferðarinnar í fjölbreyttara og stærra úrtaki þar sem allir

þátttakendur í þessari rannsókn voru konur og háskólanemar.

Efnisorð: Hárreytiröskun, húðkroppunarröskun, áreitastjórnun, vísbenda-berskjöldun, Habit reversal þjálfun, samanburðarrannsókn.

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Abstract

Objective: Hair-pulling disorder (HPD or trichotillomania) and Skin-picking disorder (SPD

or excoriation disorder) are relatively common psychiatric problems with significant public

health impact, and may have a chronic course if left untreated. The most common treatment

for individuals with HPD/SPD is SSRI medications, but is largely ineffective. The objective

of this study was to examine the efficacy of cue-exposure with response prevention (CERP)

for HPD/SPD. Habit Reversal Training (HRT), implemented with CERP, was compared to

HRT implemented with stimulus control (SC), which is the first-line treatment for HPD and

SPD.

Method: Participants were 20 university students diagnosed with either HPD (n=5) or SPD

(n=15). They were randomized to receive four one-hour weekly sessions with either HRT-

CERP (n=10) or HRT-SC (n=10). Assessment interviews took place pre- and post-treatment

and after one month follow-up.

Results: A significant reduction in symptom severity was observed in both treatment groups

on all primary outcome measures. No significant group differences were observed on self-

report scales but significant differences were found on interview-based measures with HRT-

CERP being more effective than HRT-SC in reducing symptom severity. Effect sizes

(Cohen’s d) were larger in HRT-CERP (2.27-2.96) compared to HRT-SC (1.28-1.30) on all

primary outcome measures.

Conclusions: HRT-CERP seems to be an effective treatment strategy for individuals with

HPD and SPD when compared to HRT-SC, and should be developed further for this patient

group. The sample in the present study was homogeneous in nature, with all participants

being female and university students. This should be addressed in future studies.

Keywords: Hair-pulling disorder, Skin-picking disorder, Habit Reversal Training, cue exposure, stimulus control, randomized clinical trial.

5

Acknowledgements

I would like to take this opportunity to thank my supervisors, Ragnar Pétur Ólafsson and Ívar

Snorrason, for excellent guidance and supervision throughout this entire process. I also want

to thank my research partner, Hulda María Einarsdóttir, for great collaboration. Finally, I

would like to thank my wonderful and extremely patient girlfriend, Harpa Rún Glad, for all

the support and love.

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Table of Contents

Útdráttur ..................................................................................................................................... 3

Abstract ...................................................................................................................................... 4

Acknowledgements .................................................................................................................... 5

Table of Contents ....................................................................................................................... 6

Introduction ................................................................................................................................ 8

Hair-pulling disorder (Trichotillomania) ............................................................................................ 9

Excoriation (skin-picking) disorder .................................................................................................... 9

The relatedness of HPD and SPD ..................................................................................................... 10

Treatments for HPD and SPD ........................................................................................................... 11

Habit Reversal Training (HRT) .................................................................................................... 12

Stimulus control (SC). .................................................................................................................. 12

Cue-exposure/response prevention (CERP). ................................................................................. 13

Purpose of the present study ............................................................................................................. 14

Method ..................................................................................................................................... 16

Participants ............................................................................................................................... 16

.......................................................................................................................................................... 17

Measures ........................................................................................................................................... 17

Phone screen. ................................................................................................................................ 17

Psychiatric interviews. .................................................................................................................. 17

Self-Report Measures for SPD. ..................................................................................................... 18

Self-Report Measures for HPD. .................................................................................................... 19

Other self-report measures. ........................................................................................................... 20

Procedure .......................................................................................................................................... 21

Treatments. .................................................................................................................................... 22

Phone follow-up ................................................................................................................................ 24

Therapists .......................................................................................................................................... 24

Statistical Analysis ............................................................................................................................ 24

Results ...................................................................................................................................... 26

Pre-treatment Comparisons ............................................................................................................... 26

Demographic and clinical characteristics...................................................................................... 26

Depression, anxiety, and stress (DASS-21). ................................................................................. 27

Symptom severity. ........................................................................................................................ 27

Treatment Efficacy ............................................................................................................................ 28

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Correlation between primary outcome measures. ......................................................................... 28

SPS-R/MGH-HS self-report scales. .............................................................................................. 28

SPS-R-IV/MGH-HS-IV interview. ............................................................................................... 28

CGI scores. .................................................................................................................................... 29

Session-by-session self-report mean scores. ................................................................................. 29

Other outcomes ................................................................................................................................. 30

DASS-21. ...................................................................................................................................... 30

Cue-reactivity. ............................................................................................................................... 30

SPRS/HPRS ‘Wanting’ and ‘Liking’ subscale scores. ................................................................. 30

Discussion ................................................................................................................................ 32

CERP vs SC in preventing relapse .................................................................................................... 32

Cue-reactivity. ............................................................................................................................... 33

Automatic versus focused behavior. ............................................................................................. 34

Limitations ........................................................................................................................................ 34

Strengths ........................................................................................................................................... 35

Conclusions ....................................................................................................................................... 35

References ................................................................................................................................ 36

Appendix .................................................................................................................................. 45

8

Introduction

Hair-pulling disorder (HPD; trichotillomania) and excoriation (skin-picking) disorder (SPD)

are both categorized as obsessive-compulsive and related disorders in DSM-5 (American

Psychiatric Association [APA], 2013). More specifically these disorders are often

characterized as body-focused repetitive behaviors (BFRB) (Grant, Stein, Woods, &

Keuthen, 2012) that is an umbrella term for compulsive behaviors directed toward one’s body

(Teng, Woods, Twohig, & Marcks, 2002). For many people with BFRB, hair pulling and skin

picking causes merely a frustration, but for some it results in great emotional distress and

impairment (Diefenbach, Tolin, Hannan, Crocetto, & Worhunsky, 2005; Odlaug, Kim, &

Grant, 2010; Snorrason, 2008). Both HPD and SPD are relatively common and sometimes

severe psychiatric problems with significant health impact, but have not received much

research attention (e.g. Snorrason et al., 2012). However, interest of researchers in HPD and

SPD has grown considerably the past 10 years (Grant et al., 2012).

The diagnostic criteria for both disorders are almost identical, the only difference

being what part of the body the behavior is directed at. To be diagnosed with either disorder,

the behavior must result in distress or interference in any life area (e.g. relationships,

school/work etc.) (e.g. APA, 2013; Bohne, Keuthen, & Wilhelm, 2005; Bohne, Wilhelm,

Keuthen, Baer, & Jenike, 2002) and the behavior is not better explained by symptoms of

another mental disorder or other medical conditions (APA, 2013). The 12-month prevalence

for HPD, in general population, is estimated to be 1-2% in adults and adolescents and the

disorder seems to affect females more frequently than males, at a ratio of 10:1 (APA, 2013).

The lifetime prevalence of SPD in general population is estimated to be 2-4.6% (Arnold,

Auchenbach, & McElroy, 2001; Bohne et.al., 2002; Keuthen et.al., 2000). Most SPD patients,

at least in clinical populations, are female (75-94%) and the most common age of onset is in

adolescent years (Snorrason, Belleau, & Woods, 2012).

Clinicians have differentiated between automatic and focused picking and pulling.

Focused behavior involves conscious picking/pulling that often seems to be a reaction to

unpleasant sensory, emotional and/or cognitive state (e.g., anxiety, boredom). Automatic

behavior involves habitual picking/pulling that, in contrast, occurs out of the awareness of the

patient (du Tiot, van Kredenburg, Niehaus, & Stein, 2001; Flessner, Woods, Franklin, 2008).

Even though this differentiation is convenient, these behavior styles tend to co-occur, and

overlap within patients and are rarely mutually exclusive (Duke, Keeley, Ricketts, Geffken,

& Storch, 2010). Nonetheless, this difference might influence treatment effectiveness

(Flessner et al., 2008; Walter, Flessner, Conelea, & Woods, 2009).

9

The most common treatment that individuals with HPD and SPD receive is SSRI

medication (Marks, Wetterneck, & Woods, 2006) but data shows that those medications are

often ineffective (Bloch et al., 2007). Different psychological treatments have been used to

treat HPD and SPD, for example; hypnosis, psychoanalysis, cognitive therapy, and

behavioral therapy (Marks et al., 20016; Snorrason & Björgvinsson, 2012). Cognitive

behavioral treatments (CBT) have been recommended as first line intervention for HPD and

SPD (Flessner, Board, Penzel, & Keuthen, 2010) but only one type of behavior therapy,

Habit reversal training (HRT), has been assessed in comparative studies (Snorrason &

Björgvinsson, 2012).

In this essay clinical characteristics of HPD and SPD will be described, as well as the

similarities in symptom presentation and phenomenology of both disorders. The most

common types of cognitive behavioral treatments will be discussed, including Habit Reversal

Training (HRT), stimulus control (SC) and cue exposure/response prevention (CERP).

Finally, the results of a recently completed research trial will be described, where the

effectiveness of HRT-CERP and HRT-SC for HPD and SPD was compared.

Hair-pulling disorder (Trichotillomania)

Hair-pulling disorder is characterized by repetitive pulling, and persistent inability to

resist pulling out one‘s hair (APA, 2013). The hair-pull can take place at any location on the

body where there is hair but the most common pulling areas include the scalp, eyebrows,

eyelashes, pubic region and legs (Duke, Keeley, Geffken & Storch, 2010; Woods et al.,

2006). It is common that many patients engage in a variety of habitual behaviors both before

and after pulling, for example searching for the perfect hair or eating the hair afterwards

(Mansueto, Stemberger, Thomas, & Golomb, 1997).

HPD can cause significant distress and dysfunction (Lootens, & Nelson-Gray, 2016).

Negative consequences of HPD can include bald spots, hair thinning, disruption in work or

academic functioning and social avoidance (Diefenbach et al., 2005; Woods et al., 2006).

According to Odlaug et al. (2010) individuals with HPD experience a lower quality of life

compared to controls. They also demonstrated lower self-esteem compared with non-

psychiatric control group, even after controlling for depression (Diefenbach et al., 2005).

Excoriation (skin-picking) disorder

SPD is characterized by excessive picking at one’s own skin (APA, 2013). Individuals

often use their fingernails to pick but also use instruments such as tweezers, nail files and

10

knives which often results in damage on the skin (Arnold et al. 1998; Odlaug & Grant, 2008;

Keuthen et al., 2000; Wilhelm et al., 1999). SPD, like HPD, occur in the absence of

underlying dermatological or other medical conditions, like scabies or acne (APA, 2013).

Wilhelm et al. (1999) found that 39% of patients started to pick their skin when dealing with

acne in their teenage years, and developed SPD after the dermatological condition “was

cured”. Studies show that SPD patients have lower quality of life compared to controls

(Odlaug et al., 2010). They also report a range of psychosocial and medical complications

caused by the behavior, including skin damage and infections and in most severe cases

permanent disfigurement (Odlaug & Grant, 2008; Wilhelm et al., 1999).

The relatedness of HPD and SPD

There are striking similarities in phenomenology and symptom presentation of SPD

and HPD (Bohne, Keuthen, & Wilhelm, 2005; Lochner, Simeon, Niehaus, & Stein, 2002;

Odlaug & Grant, 2008b; Snorrason et al., 2012; Teng et al., 2002). Both disorders involve

removing parts of the body (i.e. hair or skin) with recurrent behavior. People with HPD often

pull hairs that are different from other hairs (e.g. coarse or gray) and people with SPD often

target certain type of skin imperfections. It seems that in both groups seeing or feeling these

preferred features triggers episodes (Arnold et al., 1998; Odlaug & Grant, 2008b). It is

common that many patients engage in pre- and post-picking/pulling behavior like stroke the

skin to look for imperfections to pick or running fingers through hair to find hair with certain

texture. Many manipulate the skin or the hair afterwards, chew on it or eat it (Snorrason &

Björgvinsson, 2012; Snorrason, Smari & Olafsson 2011; Wilhelm et al., 1999). Normally

HPD and SPD patients use their fingers to pick or pull and some also use implements (e.g.

tweezers) (Arnold et al., 1998; Christenson, McKenzie, & Mitchell, 1991; Snorrason, Smári,

& Ólafsson, 2011; Wilhelm et al., 1999). About 33% of SPD patients report dissociation, or

some kind of trance like stage, while picking skin and more than 20% of hair-pulling patients

report experiencing depersonalization while pulling hair (Snorrason, Smári, & Ólafsson,

2010; Wilhelm et al., 1999; du Tiot et al., 2001).

One way to examine how related these disorders are, is to look at comorbidity.

Snorrason et al. (2012) reviewed the literature and found out that the prevalence of SPD in

HPD outpatient samples was on average 29.8% across studies and the prevalence of HPD in

SPD outpatient samples was on average 15.5% across studies. Lifetime prevalence of HPD in

inpatients samples is estimated to range from 1.3 to 4.4% (average 2.7% across studies)

(Grant, Levine, Kim, & Potenza, 2005; Müller et al., 2011; Tamam, Zengin, Karakus, &

11

Ozturk, 2008) and lifetime prevalence of inpatients with SPD is estimated to range from 7.3

to 11.8% (average 9,6% across studies) (Grant, Williams, & Potenza, 2007; Müller et al.,

2011). By chance, the prevalence of co-occurrence of SPD and HPD in inpatients setting

should be around 0.26% (9.6 x 2.7 = 0.26) (Snorrason et al., 2012). Thus, the overlap

between these two conditions suggests that they may be closely connected.

It also seems that both disorders have shared genetic risk factors. In an internet survey

study, 50.8% of 718 participants, that met criteria for SPD, reported having a first-degree

relative with problematic skin picking and about 8% said they had a first-degree relative with

a history of an HPD diagnosis (Snorrason et al., 2015). Novak, Keuthen, Stewart and Pauls

(2009) investigated concordance rates for HPD in a twin study with both monozygotic (MZ)

and dizygotic (DZ) twins and found out that concordance rate for MZ twins (38.1%) was far

greater than the concordance rates of DZ twins (0%) which suggests a significant genetic

component for HPD. Another twin study showed that genetic factors accounted for

approximately 40% of the variance of skin picking (Monzani et al., 2012). Monzani et al.,

(2014) examined the degree to which genetic and environmental risk factors are unique

and/or shared by OCD and related disorders (body dysmorphic disorder, hoarding disorder,

HPD and SPD). The results showed two latent factors that were substantially heritable. One

of those two latent factors loaded exclusively on HPD and SPD and all the heritability

variance was shared by the two disorders The authors suggest that SPD and HPD might

represent alternative phenotypic expressions of the same genetic condition.. In a large OCD

family study it was discovered that both SPD and HPD, but not OCD, were associated with

variants in the human Sapap3 gene further supporting the notion that SPD and HPD may

have a common genetic association (Bienvenu et al., 2009). In summary, there is strong

evidence for relatedness between SPD and HPD, including possible shared genetic risk

factors, comorbidity, and similar clinical features.

Treatments for HPD and SPD

Cognitive-behavioral interventions for SPD and HPD (and other BFRB) can be

divided into two categories. The first category includes techniques directly aimed at

preventing or stopping picking and/or pulling behavior. These techniques include habit

reversal training and stimulus control. The second category includes strategies that are aimed

at managing internal states and other possible maintaining factors, such as dialectical

behavior therapy (DBT), acceptance and commitment therapy (ACT), and cognitive therapy

(CT)) (Snorrason & Woods, 2014).

12

Habit Reversal Training (HRT). The first step in HRT is teaching the client to

become more aware of picking or pulling behaviors and preceding “warning signs”

including, urges or emotional changes, and movements early in the behavioral chain leading

up to pulling/picking (e.g., moving hand toward the scalp). The awareness training starts with

a careful functional assessment interview, were information about what happens before,

during, and after picking and/or pulling behavior are gathered. The patient is also asked to

engage in self-monitoring between sessions to further enhance his awareness of the behavior

and its context (Miltenberger, 2001). When the client has improved his awareness she is

taught to perform a physically incompatible behavior – called competing response (e.g.

sitting on one‘s hands) – whenever a warning signs or pulling/picking behaviors are detected

(Capriotti, Ely, Snorrason, & Woods, 2015; Snorrason, Berlin, Lee, 2015).

HRT is the treatment for HPD and SPD with the most empirical support (Azrin,

Nunn, & Frantz-Renshaw, 1982; Bloch et al., 2007; Franklin et al., 2011; Ghanizadeh, 2011;

Moritz, Treszl, & Rufer, 2011; Tucker, Woods, Flessner, Franklin, & Franklin, 2011) and

results show that HRT is an effective intervention for maladaptive repetitive behaviors like

HPD and SPD. Teng et al. (2006) compared HRT for SPD to a wait-list control group and

HRT was found to be more effective than the wait-list control condition and gains were

maintained at a 3 month follow-up. In addition, a meta-analysis (Bate, Malouff,

Thorsteinsson and Bhullar, 2011) based on 18 studies of HRT for a range of BFRBs showed

large effect size pre-treatment to post-treatment with d = 0.80.

Stimulus control (SC). HRT is often implemented in combination with stimulus

control (SC) interventions (Mansueto, Golomb, Thomas, & Stemberger, 2000). The goals of

SC is to make picking/pulling more burdensome or less reinforcing by identifying ways to

reduce picking/pulling opportunities in the client‘s environment. Examples of SC

interventions include removing/discard picking/pulling tools (e.g. tweezers), wear gloves,

cutting fingernails short to reduce the effectiveness of fingernails used for picking/pulling,

remove objects that facilitate picking/pulling (e.g. remove or cover bathroom mirror),

eliminate postural triggers (e.g. studying at a different desk) and restrict time in high-risk

situations (e.g. reduce time in front of mirror) (Mansueto et al., 1999). As listed above, HRT

has shown to be an efficacious intervention for both HPD and SPD. Bate et al. (2011) showed

that combined with SC it can reduce symptoms for 50-60% of individuals with HPD. Other

13

randomized controlled trials have also demonstrated similar effect for SPD (Schuck, Keijsers,

& Rinck, 2011; Teng, Woods, & Twohig, 2006). To the best of our knowledge, no study has

examined the effect of SC as a monotherapy for SPD or HPD.

Cue-exposure/response prevention (CERP). In exposure and response prevention

patients are exposed to anxiety-provoking stimuli or cues that trigger urges or longing while

abstaining from performing anxiety- or urge reducing compulsions (e.g. reassurance and

avoidance) (Sulkowski, Jacob, & Storch, 2103). Originally exposure treatment was developed

to treat fear and phobias and has proven to be effective treatment for disorders like OCD,

BDD, post-traumatic stress disorder (PTSD), and panic disorder (e.g. Javidi, Battersby, &

Forbes, 2007; Sulkowski et al, 2013). For the last thirty years or so, exposure-based

treatments, like CERP, have also been used to help patients with disorders that involve urges

and cravings, including alcohol and substance use, over-eating and gambling (Conklin &

Tiffany, 2002; Havemans & Jansen, 2003; Jansen, 1998). The main difference between

exposure treatment for fear and anxiety and for urges or addiction is that instead of exposing

individuals to anxiety provoking stimuli, they are exposed to internal or external cues that

trigger urges to engage in the addictive behavior (Boutelle & Bouton, 2015).

HPD and SPD are often conceptualized as behavioral addiction (Shusterman, Feld,

Baer, & Keuthen, 2009; Snorrason, Smari & Olafsson, 2010) and brain imaging research

indicates that individuals with HPD/SPD show abnormalities in reward circuitry that has

previously been linked to craving and addiction (Roos, Grant, Fouche, Stein, & Lochner,

2015; White et al., 2013). Studies have shown that individuals with SPD and HPD experience

strong craving for picking/pulling and also gratification and pleasure while doing so (e.g.

Snorrason et al., 2010; Diefenbach, Tolin, Meunier, & Worhunsky, 2008). According to

behavioral model of SPD and HPD picking and pulling behavior is, just like addiction,

maintained by reinforcing consequences (Mansueto et al., 2000). The pleasurable experience,

such as gratification or relief that sometimes is produced by picking and/or pulling works as a

positive automatic reinforcement. At other times, the behavior can work as a negative

automatic reinforcement if it down-regulates negative experiences such as anxiety or

boredom (Snorrason et al., 2012). The picking and/or pulling behavior (US) produces

desirable affective reaction (UR) within the individual. If the behavior is repeated, a neutral

contextual cues (NS) can be paired with the US and acquire the ability to trigger urges (CR)

to perform the behavior through classical conditioning.

14

If pulling and picking are instrumental responses that are influenced by classical

conditional cues, extinction theory can provide a useful framework to develop effective

treatments for BFRB like HPD and SPD by exposing the patient to triggering stimuli and

encourage him to experience the longing or urge to pick/pull without doing so. The object is

to extinguish the association between the conditioned cues and the behavior.

The rationale behind applying cue-exposure as a treatment for addictive behaviors is

therefore mostly based on classical conditioning models. Classical conditioning is the process

where an organism associates conditioned stimuli (CS) with a biologically meaningful event

(reinforcer), called unconditioned stimulus (US) (Woods & Ramsey, 2000). For example, in

HPD, the hair pulling is the unconditioned stimulus (US) and the desirable affective reaction

produced by the pulling is the unconditioned response (UR). The conditioned stimuli (CS) are

some contextual features (e.g. experiencing boredom/anxiety, or being alone in bedroom),

and those contextual features will evoke urges (CR) to pull and trigger hair pulling. Urges in

turn make the behavior more likely to occur. CERP is, in other words, based on behavioral

model of addictive behaviors.

Not much is known about the effect of CERP for SPD and HPD but at least two case

studies have been reported. Javidi et al. (2007) applied a cognitive-behavioral therapy

protocol, mostly based on CERP, in a treatment of a woman with HPD. The results were

impressive, with visible progress after only four treatment sessions, and gains had been

maintained at 4 years follow-up. Later, a CERP treatment was applied on an adolescent girl

with HPD and comorbid OCD and resulted in a significant reduction in pulling behavior

(Sulkowski, Jacob, & Storch, 2013). Cue exposure has also been used on patients with HPD

and SPD as a component in ACT therapy and showed promising results (Capriotti et al.,

2015; Snorrason & Woods, 2014; Twohig, & Woods, 2004). In ACT, the client is taught to

accept internal states (e.g. urges) without trying to control them or react out in anyway

(Snorrason & Woods, 2014). This is accomplished with variety of experiential exercise were

the aim is to weaken aversive internal stimuli, and break the discriminative control of urges

and negative affect over overt behavior (Capriotti et al., 2015).

Purpose of the present study

The aim of the present study is to examine the efficacy of HRT-CERP for HPD/SPD

by comparing it to HRT-SC, which is a first-line treatment for these conditions. Previous

studies have shown that HRT-SC consistently results in significant reduction in symptoms

15

from pre to post treatment. However, relapse rates are high after recovery (Capriotti et al.,

2015; Rhem, Moulding, Nedeljkovic, 2015; Snorrason et al., 2015). The goal of SC is to

reduce picking and/or pulling opportunities in the environment. Unfortunately, SC may at the

same time reduce the number of extinction trials that the patients can practice the competing

response in high-risk situations. Therefore, it is possible that SC interventions can

compromise the long-term outcome of HRT. Some researchers have also suggested that

internal events like urges, impulses, and aversive affects may play important role in

promoting relapse. possibly be more effective in treating these problems (Keuthen et al.,

2011; Woods, Wetterneck, & Flessner, 2006) but those internal events are not treated directly

in HRT-SC. However, in HRT-CERP, the numbers of extinction trials will increase and

internal events are also treated. Thus, in this randomized controlled clinical trial, HRT-CERP

was compared to HRT-SC. Twenty university students diagnosed with either HPD or SPD

were randomized to receive either HRT-SC or HRT-CERP. It was hypothesized that HRT-

CERP would show similar effect as HRT-SC at post-assessment (hypothesis 1). It was also

hypothesized that the relapse rate would be lower for HRT-CERP at the one-month follow-

up, but the results of the follow-up will not be discussed in this essay.

The design of the study also allowed to explore mechanisms of change -if cue-

reactivity would decrease from pre to post treatment and if the magnitude of the decrease

would differ between treatment conditions. It was expected that cue-reactivity would

decrease from pre- to post treatment (hypothesis 2). It was also expected that this reduction

would be greater in HRT-CERP because it explicitly targets high-risk situations and

encourages clients to experience strong urges without picking that may extinguish negative or

positive reinforcement contingencies in HPD and SPD (hypothesis 3).

16

Method

Participants

Participants were recruited by sending an invitation via email to all students registered

at the University of Iceland (N≈10.000). Subsequently, the participants who responded to the

email were contacted and a phone screening was performed. Total of 124 individuals (82%

female) responded to the recruitment email and underwent phone screening to determine

eligibility. Eligible participants were then invited to an assessment interview which also

included more thorough screening. Inclusion and exclusion criteria can be seen in Table 1.

After phone screening, 24 (23 female) participants were invited to the pre-assessment

interview that was also used as a more thorough screening. Four participants were excluded

because they did not meet the inclusionary or the exclusionary criteria. The participant flow

can be seen on the consort diagram in Figure 1. As displayed in the consort diagram, 20

participants diagnosed with either SPD (n=15) or HPD (n=5), enrolled into randomization.

Enrolled participants were all female and the mean age was 26.5 years (SD=5.4).

Table 1

Inclusion / exclusion criteria

Inclusion criteria

a. A primary DSM-5 diagnosis of SPD or HPD

b. Not currently receiving psychotherapy for SPD or HPD

c. Participant could be on psychotropic medications, but must agree not to alter the dosage

of the medication, or start new medication, during the course of treatment

d. Committed to a 4 week treatment

e. Willing to be randomized

Exclusionary criteria

a. A lifetime diagnosis of Bipolar I Disorder, Psychotic Disorder, Autism spectrum

disorders

b. Current major depressive episode, severe

c. Current diagnosis of substance use disorder (except nicotine dependence)

d. Current suicidal risk

17

Measures

Phone screen. The phone screening consisted of a 16-item interview form

constructed by the researchers, with question regarding HP/SP behavior, current DSM-5

diagnostic criteria for SPD and HPD, and inclusion/exclusion criteria.

Psychiatric interviews.

The Mini International Neuropsychiatric Interview. (MINI; Sheehan et al., 1997) is

a semi structured diagnostic interview that screens for the most common mental disorders of

the DSM-IV (APA, 2000). The interview has good psychometric properties and high

correlation with longer and more comprehensive diagnostic interviews (Lecrubier et al, 1997;

Sheehan et al., 1997). The Icelandic version, translated by Pétur Tyrfingsson, has

psychometric properties that are comparable to the original version (Sigurðsson, 2008). The

present study employed a composite version of the MINI and the Body Dysmorphic Disorder

(BDD) module of MINI-plus with additional questions.

Clinical Global impression (CGI) Scale. This is a semi-structured interview that

assesses overall impairment and treatment response. The interview has two items, a 7 point

Figure 1. Consolidated Standards of Reporting Trials (CONSORT) diagram of participants flow.

18

impairment scale and a 7 point improvement scale. This interview is considered by many as

the gold standard in research on effectiveness of psychological and pharmacological

treatments of psychiatric problems (Bushner & Targum, 2007; Guy & Bonato, 1970).

Problematic Habit Interview Schedule (PHIS). This is a semi-structured interview

designed to assess the DSM-5 diagnoses and clinical characteristics of HPD and SPD. The

interview assesses both current and past skin-picking/hair-pulling habits, and whether current

HP/SP behavior meets DSM-5 criteria for HPD or SPD. In particular, the interview examines

whether HP/SP results in (1) skin lesion/hair-loss, (2) emotional distress, (3) impairment in

functioning, (4) desire to stop or reduce behavior, and (5) previous attempts to stop or reduce

behavior. The interview also assesses if behavior is solely due to a medical condition,

substances or another psychiatric disorder (Snorrason, Belleau, & Lee, unpublished). The

interview was translated to Icelandic by Ívar Snorrason.

Skin Picking Scale-Revised Interview Version (SPS-R-IV). This is an interview

version of the SPS-R self-report scale that is described below.

MGH Hair Pulling Scale Interview Version (MGH-HPS-IV). This is an interview

version of the MGH-HP self-report scale that is described below.

Prior treatment history interview. Information about prior treatment history was

gathered in the pre-assessment interview. Participants were asked if they had mentioned the

disorder, or sought treatment, from a healthcare professional (e.g. psychiatrist or

psychologist). If so they were asked about what kind of intervention or reaction they

received. The interview was designed by the research group to evaluate the knowledge and

treatment on HPD/SPD by healthcare professionals in Iceland.

Self-Report Measures for SPD.

Skin Picking Scale-Revised (SPS-R). SPS-R is an 8 item self-report scale that was

designed to measure the severity of skin-picking during the past week. It has two subscales;

Symptom severity that consists of items assessing frequency and intensity of urges, time

spent picking and control over the skin-picking behavior. The other subscale is Impairment

that consists of items assessing emotion distress, functional impairment, skin damage and

social avoidance. All the items are rated on a 5 point scale that ranges from 0 (none) to 4

(extreme). The scale was translated to Icelandic by Ívar Snorrason. The scale has good

psychometric properties (Snorrason et al., 2012).

Milwaukee Inventory for Dimensions of Adult Skin Picking (MIDAS). MIDAS is a

12-item self-report scale that is designed to measure focused and automatic style of skin-

19

picking. Each subscale consists of 6 items. Focused skin-picking is when behavior is done

with full awareness in response to urges or negative affective states. Automatic style is

characterized by picking without reflective awareness. All items are rated on a 5 point scale

ranging from 1 (not true for any of my picking) to 5 (true for all my picking). The scale was

translated to Icelandic by Ívar Snorrason. Walther, Flessner, Conelea, and Woods (2009)

demonstrated acceptable psychometric properties of both scales.

Skin Picking Reward Scale (SPRS). SPRS is a 12-item scale that is designed to

assess how much an individual wants and likes to pick skin. It has two subscales; wanting

(motivational drive to engage in picking) that consists of 6 items and liking (pleasurable

experience during picking) that also consists of 6 items. The items are rated on a scale from 1

(almost never) to 4 (almost always). The scale was translated to Icelandic by Ívar Snorrason.

Snorrason, Ólafsson, Houghton, Woods, and Lee (2015) showed that the psychometric

properties of the scale are good.

Self-Report Measures for HPD.

Massachusetts General Hospital Hair pulling Scale (MGH-HS). MGH-HS is a

seven-item self-report scale that measures urge frequency, intensity, and controllability. It

also measures hair pulling frequency, resistance, and controllability, and associated distress

during the prior week. All items are rated on a 5-point scale with ratings from 0 to 4. The

total score ranges from 0-28, with higher score indicating greater severity. The scale was

translated to Icelandic by Ívar Snorrason. The scale has excellent test-retest reliability and

good convergent and divergent validity (Diefenbach, Tolin, Crocetto, Maltby, & Hannan,

2005; Keuthen et al., 1995).

Milwaukee Inventory for Subtypes of Trichotillomania-Adult Version (MIST-A).

MIST-A is a 15 item self-report scale that measures focused and automatic pulling. The

focused pulling scale has ten items and the automatic scale has five items. The items are rated

from 0 to 9 with focused scale score ranging from 0-90 and automatic scale score from 0-45.

According to Flessner et al. (2008) the scale has a satisfactory internal consistency and good

convergent and divergent validity. The scale was translated to Icelandic by Ívar Snorrason.

Hair Pulling Reward Scale (HPRS). HPRS is designed to assess how much an

individual wants (motivational drive to engage in pulling) and likes (pleasurable experience

during pulling) to pull hair. This scale is identical to the Skin Picking Reward Scale, the only

difference being that this scale assesses how much the individual wants and likes hair-pulling,

not skin-picking. The scale was translated to Icelandic by Ívar Snorrason. The self-report

20

scale is a 12-item scale. It has two subscales, wanting and liking that both consists of 6 items.

The items are rated on a scale from 1 (almost never) to 4 (almost always) and a previous

study has shown that it has good psychometric properties (Snorrason et al., unpublished).

Other self-report measures.

Depression Anxiety and Stress Scale 21-item version (DASS-21). The DASS-21 is a

21-item questionnaire designed to measure symptoms of depression, anxiety, and stress in

both clinical and non-clinical populations. Each domain contains seven items in which the

respondent has to indicate the extent to which a statement applies to him using a 4-point

Likert scale. Studies show that all three scales have good psychometric properties (Anthony,

Bieling, Cox, Enns, & Swinson, 1998). The Icelandic version was translated by Pétur

Tyrfingsson and the translated version shows good psychometric properties, good convergent

and divergent validity on depression and anxiety scales but results are unclear for the stress

scale (Ingimarsson, 2010).

Not Just Right Experiences-Questionnaire-Revised (NJRE-Q-R). The NJRE-Q-R is

a 19-item questionnaire that is designed to assess a general tendency for not just right

experiences. In the beginning there is a list of 10 common NJRE and the respondent is asked

to indicate whether or not they have experienced them in the past month. The sum of these

items yields NJRE-Q-R variety score. The respondent is asked to select the most recent NJRE

and rate it on seven severity items. The sum of these items yields NJRE-Q-R- Severity score

(Coles, Frost, Heimberg, & Rheaume, 2003). The scale was translated to Icelandic by Ragnar

P. Ólafsson but psychometric properties are unclear in the Icelandic version.

Intolerance of Uncertainty (IUS). The IUS is a 27-item self-questionnaire that is

used to measure participants level of uncertainty of intolerance. In this scale uncertainty is

being perceived as a stressful and upsetting phenomena, uncertainty leading to the inability to

act, or uncertain events being perceived as negative and should be avoided. The respondent is

asked to rate items on a 5-point Likert scale range from 1 (“not at all characteristic of me“)

to 5 (“entirely characteristic of me“) (Freeston, Rhéaume, Letarte, Dugas, & Ladocuer,

1994). The IUS has been shown to have excellent internal consistency and good test-retest

reliability over a 5 week period (Buhr & Dugas, 2002). The Icelandic version was translated

by Ragnar P. Ólafsson.

Paper/pencil cue reactivity test. In this simple cue-reactivity test, responders are

presented with a written instruction and asked to imagine pulling/picking at the present

moment. Then they are asked to answer two questions; 1) How pleasurable would it be to

21

pick skin/pull hair at this moment? 2) How much gratification would you experience if you

picked skin/pulled hair right at this moment? Both items are rated on a 0-10 scale with ends

labeled not at all pleasant to extremely pleasant. Both items are administered twice – before

and after the administration of self-questionnaires about positive aspects of skin picking/hair

pulling. The greater before-after increases in the pleasure/gratification ratings suggest greater

cue-reactivity (Snorrason et al., 2015).

Satisfaction questionnaire. Participant’s satisfaction and opinion about the treatment

and treatment factors were evaluated on a 14-item self-report questionnaire, divided into 4

subscales. The first subscale measured how much the client’s knowledge on SPD/HPD had

increased after treatment. Second subscale measured how useful the client evaluated different

treatment factors. The third subscale assessed the likelihood of certain treatment factors to be

used if relapse would occur. The last subscale evaluated the similarity between this treatment

protocol and prior treatment. Only participants with prior treatment history answered the last

subscale. All items are rated on a 5-point scale with ratings of 1 to 5, the higher the score the

higher was the satisfaction and positive opinion.

Picture ratings. Pictures of hair loss or skin damage were taken pre and post

treatment. Independent evaluators, blind to the purpose of the study, will be asked to rate the

severity of the hair loss/skin damage for each photo. Average score of each subject, across

raters, will be compared from pre and post treatment. The pictures will not be used to

evaluate treatment progress in this essay.

Procedure

The study was approved by the Icelandic data protection authority and the National

Bioethics Committee. All the students who answered the email invitation went through a

brief phone screening. Participants deemed eligible during phone screening were invited to a

baseline assessment that included more thorough screening. After signing an informed

consent and answering general background information that consisted of question about

participant’s age, gender, marital status and their educational level, participants completed a

package of self-report questionnaires (described above). The package included the following

self-report questionnaires: general background information; paper/pencil cue reactivity test

package; SPS-R/MGH-HS; DASS-21; IUS; NJRE-QR. After completing the self-report

questionnaires, participants underwent a psychiatric interview that included interview about

prior treatment history, PHIS, SPS-R-IV or MGH-HS-IV, CGI, and MINI. At the end of the

baseline assessment pictures were taken of picking/pulling locations on each participant.

22

Eligible participants were randomized to either treatment condition. The randomization into

treatment groups was issued by an individual independent from the study itself. The primary

diagnosis of HPD and SPD was used as a variable block in the randomization into treatment

groups so the ordering was as equal as possible with two individuals with HPD in HRT-SC

and three individuals with HPD in HRT-CERP. First treatment session was scheduled within

seven days from the baseline session.

Treatments. The treatment for both groups consisted of HRT that included self-

monitoring, awareness training, competing response, and relapse prevention methods. Both

treatment groups also got psychoeducation and motivational enhancement alongside with

HRT. The difference between the groups was that ten participants got HRT implemented with

CERP and ten participants got HRT implemented with SC. Both treatment protocols were

developed by Snorrason and Ólafsson (unpublished), and adapted from existing protocols.

The treatment packages consisted of four 1-hour individual sessions that were conducted

weekly. In table 2 is an overview of session by session of both treatment forms.

Table 2

Session by session overview of both treatments

HRT-SC HRT-CERP

Session#1

Psychoeducation; treatment rationale

Functional assessment

Motivational enhancement

Homework assignment: self-monitoring;

psychoeducation; motivational assignment

Psychoeducation; treatment rationale

Functional assessment

Motivational enhancement

Homework assignment: Self-monitoring;

psychoeducation; motivational assignment

Session#2

Review homework

Awareness training

Assign competing response (CR)

Develop stimulus control (SC) intervention

Homework assignment: self-monitoring; CR; SC

intervention

Review homework

Awareness training

Fill out exposure hierarchy

Assign competing response (CR)

In-session cue exposure

Post-exposure processing

Homework assignment: self-monitoring; cue

exposure; CR

Session#3

Review homework

SC intervention

CR problem-solving

Homework assignment: self-monitoring; CR; SC

intervention

Review homework

CR problem-solving

In-session cue exposure

Post-exposure processing

Homework assignment: self-monitoring; cue-

exposure; CR

Session#4

Review homework

SC intervention

CR problem-solving

Relapse prevention

Review homework

CR problem-solving

In-session cue exposure

Post-exposure processing

Relapse prevention

23

HRT and other shared treatment factors. The psychoeducation was the same for both

treatment groups except for the treatment rationale. The goal of the education was to provide

general information on the disorder and the treatment. All participants were provided with a

psychoeducational handout and encouraged to read further educational material on their own.

Two exercises were used in motivational enhancement. In session the client was

asked to list costs and benefits associated with continuing pulling/picking, and stop

pulling/picking. Then the costs and benefits of either option were evaluated. For homework

after first session the participants got either inconvenience review or the magic wand thought

experiment. In the inconvenience review the client was asked to list negative consequences of

HP/SP that covers different life domains. In the magic wand thought experiment the client

was asked to imagine and write down how their life would be different if the habit would

disappear.

Considering that the behavioral model of HPD/SPD assumes that the behavior is

maintained by reinforcing consequences the functional assessment consisted of questions that

assessed (1) antecedents of hair pulling (e.g. cues that evoke urges, discriminative stimuli that

signals upcoming HP/SP reward), (2) detailed description of HP/SP episode and (3) negative

and positive consequences of HP/SP.

One of the main elements in HRT is awareness training. The following three activities

were used to increase the client’s awareness of the behavior. (1) Through functional

assessment interview, (2) with self-monitoring which can also provide valuable information

about high-risk situations and (3) with in-session exercises. During a casual conversation

with the client the therapist performed a warning sign and the client had to indicate when he

identified the sign. Then the roles were reversed.

When the client had become efficient with identifying warning signs she was

introduced to a competing response. The client was instructed to perform a competing

response every time she noticed a warning sign or found herself picking/pulling. The CR

should be performed for 1 minute or until the urge was gone. The client was also asked to

demonstrate the competing responses in session.

The relapse prevention was mainly a discussion about the difference between a lapse

and a relapse. The client was also helped to identify emotions, thoughts, and situations that

signals upcoming lapse or relapse and coping strategies were designed to deal with them.

The difference between the treatment groups. In cue-exposure exercises, the client

was asked to evoke the urge to pull/pick while at the same time do nothing to relief the urge

24

(i.e., not allowed to pull/pick or to engage in any distraction). In the beginning stages of

treatment exposure hierarchy was created with the client, based on information from the

functional assessment. Before every exercise clients beliefs and expectations were

documented to set up for potential expectancy violation.

The main focus of stimulus control is to figure out ways to change the client’s

environment so pulling/picking behavior becomes more effortful and/or less rewarding. All

stimulus control interventions were chosen in collaboration with the client and were selected

based on the information gathered from the functional assessment.

Phone follow-up

Approximately one month after last treatment session, participants received a phone

call from the therapists and the following measurements were used to assess the current

situation regarding HP/SP behavior; PHIS, SPS-R-IV/MGH-HP-IV and CGI. The results of

the 1-month phone follow up will not be discussed in this essay.

Therapists

The treatments were delivered by two therapists who were master’s-level students in

clinical psychology at the University of Iceland. Both therapists were carefully trained to

deliver both treatments. Supervision- and consult meetings were held at least weekly over the

course of treatment. Every treatment session was audio-recorded and random session listened

to by supervisors.

Statistical Analysis

The statistical program IBM SPSS statistic data editor version 20 was used for

processing of data. T-tests and Fisher’s exact tests were used for group comparisons at

baseline. A two-tailed (superiority) mixed ANOVAs, with treatment groups as between-

subjects factor and time of assessment (pre vs. post treatment) as the within-subjects factor,

were used to test for changes during treatment and in interaction with type of treatment.

Cohen‘s d effect sizes were calculated from mean difference between the groups that

was divide by the pooled standard deviation of the means. Cohen (1988) suggests that

d=0.2 should be considered a 'small' effect, 0.5 a 'medium' effect and 0.8 a 'large' effect size.

Because the self-report questionnaires SPS-R and MGH-HS contained eight and

seven items each, average scores were constructed by dividing the total score with number of

25

items in each questionnaire. The resulting average score is on a scale from 0 to 4 (i.e. the

response scale).

The total missing value count was six data points on four different self-report

questionnaires. Due to the fact that the frequency of missing values was low, every missing

value was replaced with the most frequent response choice on that questionnaire (or scale) for

each participant.

26

Results

Pre-treatment Comparisons

Demographic and clinical characteristics. Descriptive statistics for demographic

and clinical variables for both groups are presented in Table 3. All participants were female

and mean age was similar across groups. All participants were university students so the

educational level was similar.

The background of participants was generally similar across groups. Number of

comorbid psychiatric problem was similar in both groups but four participants had current

diagnosis of MDD in HRT-SC group against two participants in HRT-CERP.

Table 3

Demographic information by condition

Variable

HRT-SC

(n=10)

HRT-CERP

(n=10) Test statistics p

Age mean (SD) 25.2 (2.2) 27.5 (7.3) 6.52a 0.36

Marital status n

3.33b 0.17

Single 8 4

Married or cohabiting 2 6

Educational level n

0.95b 0.63

Studying for a bachelor degree 7 6

Finished bachelor degree 3 4

Primary diagnosis n

0.27b 1.0

HPD 2 3

SPD 8 7

Automatic or focused behavior n 1.82b 0.37

Automatic 4 7

Focused 6 3

Comorbid disorders according to MINI n 0.20b 1.0

one disorder 2 3

two or more 3 2

…of those with MDD 4 2 0.95b 0.63

Note: SD=Standard deviation. HRT-SC=Habit Reversal Training – Stimulus Control; HRT-CERP=Habit Reversal Training

– Cue Exposure with Response Prevention; HPD=Hair-Pulling Disorder; SPD=Skin-Picking Disorder; MDD=Major

Depressive Disorder. a Independent samples t-test bFisher’s Exact Test - with 2 tailed significance

27

Depression, anxiety, and stress (DASS-21). Table 4 shows baseline severity of

anxiety, depression and stress for both treatment groups. There was no significant difference

in the total DASS-21 score between HRT-SC and HRT-CERP conditions before treatment;

t(18)=0.22, p=0,828, and no significant differences emerged on the subscale level of the

DASS either (p >0.10 in all cases).

Symptom severity. Table 4 displays the scaled mean scores of SPS-R / MGH-HS,

SPS-R-IV / MGH-HS-IV, and CGI at baseline for both groups. There were no group

differences on SPS-R/MGH-HS; t(18)=0.153, p=0.880, SPS-R-IV/MHG-HS-IV;

t(18)=0.522, p=0.608 or CGI severity scale t(18)=0.399, p=0.695 before treatment.

Table 4

Mean scores for measures of symptom severity pre- and post-treatment and effect sizes for both

treatment groups (n=10 in both treatment groups).

Pre-treatment Post-treatment

Measurements M (SD) M (SD) Cohen‘s d

DASS-21

Anxiety

HRT-SC 7.60 (8.47) 4.60 (4.10) 0.45

HRT-CERP 6.40 (6.45) 4.20 (5.20) 0.38

Both groups 7.00 (7.36) 4.40 (4.57) 0.42

Depression

HRT-SC 16.40 (13.56) 10.60 (11.5) 0.46

HRT-CERP 12.20 (9.91) 5.80 (6.5) 0.76

Both groups 14.30 (11.74) 8,20 (9.45) 0.57

Stress

HRT-SC 14.00 (8.74) 9.20 (4.0) 0.71

HRT-CERP 17.00 (9.13) 12.00 (9.97) 0.52

Both groups 15.50 (9.13) 10.60 (7.54) 0.59

Total score

HRT-SC 38.00 (26.0) 24.40 (16.1) 0.63

HRT-CERP 35.60 (22.5) 22.00 (20.9) 0.63

Both groups 36.80 (23.74) 23.20 (18.24) 0.64

HPD/SPD symptom severity

Self-reports (SPS-R/MGH-HS)1

HRT-SC 2.20 (0.55) 1.40 (0.64) 1.30

HRT-CERP 2.19 (0.47) 0.90 (0.51) 2.50

Both groups 2.21 (0.51) 1.19 (0.62) 1.80

Interview versions(SPS-R-IV/MGH-

HS-IV)1

HRT-SC 2.24 (0.42) 1.45 (0.75) 1.29

HRT-CERP 2.14 (0.44) 0.81 (0.45) 2.96

Both groups 2.19 (0.43) 1.13 (0.69) 1.72

CGI-Severity

HRT-SC 4.50 (1.18) 2.80 (1.47) 1.28

HRT-CERP 4.30 (1.06) 1.80 (1.14) 2.27

Both groups 4.40 (1.10) 2.30 (1.38) 1.68 Note: M=mean; SD=standard deviation; DASS-21=Depression Anxiety Stress Scale-21item; SPS-R=Skin Picking Scale-Revised; MGH-HS=Massachusetts General Hospital-Hair-pulling Scale; SPS-R-IV=Skin Picking Scale-Revised-Interview Version; MGH-HS-

IV=Massachusetts General Hospital-Hair-pulling Scale-Interview Version; CGI= Clinical Global Scale; HRT-SC=Habit Reversal Training

– Stimulus Control; HRT-CERP=Habit Reversal Training – Cue Exposure with Response Prevention. 1Scaled mean score because of different item count on each list. In appendix I is a table that displays total scores from self-report and

interview version for each participant.

28

Treatment Efficacy

Correlation between primary outcome measures. The correlation between

SPSR/MGH-HS, SPS-R-IV/MGH-HS-IV, and CGI-severity scale at pre and post treatment is

shown in Table 5. There was a significant relationship between SPS-R/MGH-HS and SPS-R-

IV/MGH-HS-IV in the pre-assessment. There was also a significant relationship between

SPS-R/MGH-HS and SPS-R-IV/MGH-HS-IV post-assessment. This strong correlation

indicates that there was convergence between ratings of symptom severity between

participants and therapists, at both pre and post treatment.

SPS-R/MGH-HS self-report scales. A 2(time: pre- vs. post-assessment) x

2(treatment group; HRT-SC vs. HRT-CERP) mixed design ANOVA was conducted. There

was a significant main effect for SPS-R/MGH-HPS across the two time points,

F(1,18)=45.95, p<0.001. No significant main effect of group was found, F(1,18)=1.945,

p=0.180, nor an interaction between time and group, F(1,18)=2.50, p=0.131. Effect size was

calculated to gain further insight into clinical significance of the improvement achieved in the

two conditions as displayed in Table 4.

SPS-R-IV/MGH-HS-IV interview. A 2(time: SPS-R-IV/MGH-HS-IV; pre- vs. post-

assessment) x 2(treatment group; HRT-SC vs. HRT-CERP) mixed design ANOVA was

conducted. There was a significant main effect for HP and SP severity across the two time

Table 5

Correlations between self-administered and interview based assessment of symptom severity at pre

and post treatment

1 2 3 4 5 6

1. SPS-R/MGH-HS pre treatment ―

2. SPS-R-IV/MGH-HS-IV pre

treatment

.841** ―

3. CGI-severity scale pre

treatment

.040 .145 ―

4. SPS-R/MGH-HS post

treatment

.252 .511* .153 ―

5. SPS-R-IV/MGH-HS-IV post

treatment

.268 .510* .315 .934** ―

6. CGI-severity scale post

treatment

-.068 .167 .439 .807** .822** ―

Notes: SPS-R=Skin Picking Scale-Revised; MGH-HS=Massachusetts General Hospital-Hair-pulling Scale; SPS-R-IV=Skin Picking

Scale-Revised-Interview Version; MGH-HS-IV=Massachusetts General Hospital-Hair-pulling Scale-Interview Version; CGI= Clinical

Global Scale *p<0.05, **p<0.01

29

points, F(1,18)=75.74, p<0.001. There was also a significant interaction between time and

group, F(1,18)=4.798, p=0.042. No significant main effect of group was found,

F(1,18)=3.169, p=0.092. This indicates that there was no significant difference between the

groups at pre-assessment however the mean scores from SPS-R-IV/MGH-HS-IV are

significantly lower for HRT-CERP compared to HRT-SC at post-assessment.

Effect size was calculated to gain further insight into clinical significance of the

improvement achieved in the two conditions as displayed in Table 4. The effect size for

HRT-SC measured on SPS-R-IV/MGH-HS-IV interview was 1.29 but 2.96 for the HRT-

CERP group.

CGI scores. A 2(time: CGI-Severity scale; pre- vs. post-assessment) x 2(treatment

group; HRT-SC vs. HRT-CERP) mixed designed ANOVA was conducted. There was a

significant main effect for CGI severity across the two time points, F(1,18)=51.88, p<0.001.

No significant main effect of group was found, F(1,18)=1.68, p=0.211, or an interaction

between time and group, F(1,18)=1.88, p=0.187. This indicates that both treatments have

significant effect on CGI severity score but the effect did not differ between groups.

Effect size was calculated to gain further insight into clinical significance of the

improvement achieved in the two conditions as displayed in Table 4. The effect size for

HRT-SC measured on CGI-severity scale was 1.28 but 2.27 for the HRT-CERP group.

The CGI-improvement scale showed that 40% of patients in HRT-SC were estimated

by researchers to be “much” or “very much” improved after treatment. 70% of participants in

HRT-CERP were estimated to be “much” or “very much” improved after treatment.

Session-by-session self-report mean scores. Table 6 displays the session-by-session

mean score of SPS-R/MGH-HS for both treatment groups over the course of treatment. The

mean score of those in HRT-CERP gradually decreased over time. In the HRT-SC the mean

score decreased throughout treatment but remained relatively stable from session#4 to post-

assessment.

Table 6

The scaled mean score of SPS-R/MGH-HS from pre assessment to post-assessment for both groups

Treatment groups Pre -

treatment

Session #1 Session #2 Session #3 Session #4 Post -

treatment

HRT-SC – Mean (SD) 2.23 (0.55) 1.98 (0,57) 1.76 (0.48) 1.53 (0.52) 1.41 (0.63) 1.45 (0.64)

HRT-CERP – Mean (SD) 2.19 (0.47) 2.12 (0.61) 1.68 (0.45) 1.43 (0.62) 1.07 (0.62) 0.94 (0.51)

30

Other outcomes

DASS-21. A 2(time: DASS-21 total score; pre- vs. post-assessment) x 2(treatment

group; HRT-SC vs. HRT-CERP) mixed design ANOVA was conducted. There was a

significant main effect for time, F(1,18)=9.616, p=0.006. No significant main effect of group

was found, F(1,18)=0.0, p=1.0, nor an interaction between time and group, F(1, 18)=0.077,

p=0.785. This means that significant reductions in DASS scores were observed following

treatments, that were not qualified by type of treatment. Effect sizes were moderate in size

(table 4).

Cue-reactivity. It was hypothesized that cue-reactivity would decrease from pre to

post treatment in the HRT-CERP. However, no significant changes were observed as a result

of the cue in the cue-reactivity test pre- or post treatment. This means that changes in cue-

reactivity as a result of the treatment could not be assessed.

SPRS/HPRS ‘Wanting’ and ‘Liking’ subscale scores. It was examined if the

change in the wanting and liking subscale from SPRS/HPRS correlated with the change in

SPS-R/MGH-HS and SPS-R-IV/MGH-HS-IV severity scores. As displayed in Table 7, the

correlation between the change in ‘wanting’ and the changes in severity of symptoms was

non-significant. The correlation between the change in ‘liking’ and the change in SPS-

R/MGH-HS scores was significant, r(18)=0.537, p=0.0145, and the change in liking and

SPS-R-IV/MGH-HS-IV was also significant, r(18)=0.500, p=0.025. This moderately strong

correlation suggests that changes in positive attitudes towards pulling/picking behavior and

changes in symptom severity are related.

Change in SPRS/HPRS ‘Wanting’ subscale score. A 2(time: ‘wanting’; pre- vs.

post-assessment) x 2(treatment group; HRT-SC vs. HRT-CERP) mixed design ANOVA was

conducted. There was a significant main effect for time, F(1,18)=11.35, p=0.03. No

significant main effect of group was found, F(1,18)=19.6, p=0.449, nor an interaction

between time and group, F(1,18)=0.196, p=0.663. This means that there was a significant

change in wanting scores following treatment that was not qualified by type of treatment.

Change in SPRS/HPRS ‘Liking’ subscale score. A 2(time: ‘liking’; pre- vs. post-

assessment) x 2(treatment group; HRT-SC vs. HRT-CERP) mixed design ANOVA was

conducted. No significant main effect of group was found, F(1,18)=3.23, p=0.736 but there

was a significant interaction between time and group, F(1,18)=4.50, p=0.048. No differences

were observed between the groups pre-treatment but mean scores from the ‘liking’ subscale

31

from SPRS/HPRS were significantly lower for HRT-CERP group compared to HRT-SC at

post-assessment.

Table 7

Correlation matrix of pre-post treatment difference from self-reports, interview versions, and

‘Liking’ and ‘Wanting’ subscales

1 2 3 4

1. SPS-R/MGH-HS pre-post difference ―

2. SPR-R-IV/MGH-HS-IV pre-post difference 0.849**

―

3. SPRS/HPRS ‘Liking’ subscale pre-post difference 0.537* 0.500

* ―

4. SPRS/HPRS ‘wanting’ pre-post difference 0.295 0.335 0.357 ―

Notes: SPS-R=Skin Picking Scale-Revised; MGH-HS=Massachusetts General Hospital-Hair-pulling Scale; SPS-R-IV=Skin Picking

Scale-Revised-Interview Version; MGH-HS-IV=Massachusetts General Hospital-Hair-pulling Scale-Interview Version; SPRS=Skin-

Picking Reward Scale; HPRS=Hair-Pulling Reward Scale *p<0.05, **p<0.01

32

Discussion

The primary aim of the present study was to examine the efficacy of HRT-CERP as a

treatment for HPD/SPD. A secondary aim of the study was to examine if cue-reactivity

would decrease from pre to post treatment and if this decrease would differ between the

HRT-CERP and HRT-SC.

The results showed that both HRT-CERP and HRT-SC significantly reduced

symptoms of HPD and SPD, according to all outcome measures, including self-report

questionnaires (SPS-R-IV/MGH-HS), the symptom severity interview (SPS-R-IV/MGH-HS-

IV) and general clinical impression (CGI). Comparison between the treatments suggested an

overall equal efficacy. In general, these results suggest HRT-CERP can beat least, equally as

efficacious as HRT-SC, which is an established first-line treatment for HPD and SPD. If

anything, the HRT-CERP may have been slightly superior to HRT-SC in the sample. In all

measurements assessing HPD/SPD symptom severity the effect size was larger for HRT-

CERP in comparison to HRT-SC. Moreover, HRT-CERP did show significantly greater

efficacy according to the symptom severity interview and CGI-Improvement. The reason for

the difference between interviews and self-report measures is unclear. One possibility is that

interviewer was able to identify clinically meaningful improvement in symptoms not reported

by the participants. However, the correlation between the self-report and the interview

versions was very high after treatment, which indicates that there was a similarity between

how the participants and interviewer rated the severity of symptoms. Further studies in larger

samples, with independent raters blind to treatment condition and study purpose, are needed

to confirm these results.

CERP vs SC in preventing relapse

HRT-SC is an empirically supported first-line treatment for HPD and SPD. However,

as noted in the introduction the relapse rate is relatively high after recovery in HRT-SC

(Capriotti et al., 2015; Rhem, Moulding, Nedeljkovic, 2015; Snorrason et al., 2015). It is

believed that HRT works in part by extinguish negative reinforcement contingency between

picking/pulling urges, picking/pulling behavior and subsequent reinforcing experiences

(Mansueto et al., 1999). In HRT, the patient is taught to engage in a competing response

every time an urge or other signals to pick or pull occurs. By doing so the patient undergoes

repeated naturalistic extinction trials. However, when HRT is implemented with SC, the goal

of SC is to reduce pulling/picking opportunities and avoid high-risk situations (Mansueto et

33

al, 1999). Therefore, SC can reduce the number of extinction trials for the patient to practice

in. Even though SC may be effective to reduce picking/pulling in the short-run, it may

enhance relapse rates by reducing the chances to practice in high-risk situations.

Instead of avoiding environmental factors or cues that provoke the urge to pull/pick,

in CERP the patient is encouraged to experience those urges without pulling or picking in

those difficult situations. With repeated exposure to those cues and triggers in the absence of

pulling/picking the association between the cues and the behavior will extinguish and the

cues will no longer evoke the urge to pick/pull (Hoogduin, 1997). With this repeated

exposure and expectancy violation on set of beliefs about the behavior and the urges, the

patients in the HRT-CERP group will get new information about the triggering stimuli.

Therefore, the patient will be more able to handle cues and triggers in the future and less

likely to relapse.

In conclusion, it can be argued that HRT-CERP is better able to prevent relapse after

treatment, compared to HRT-SC. Therefore, it was hypothesized that participants in HRT-

CERP would have maintained treatment gains better than participants in HRT-SC at one

month follow-up. Unfortunately, the follow-up measures were not available at the time when

this essay was due. These results will be reported elsewhere.

Mechanisms of Change

Despite small sample size, preliminary analyses were conducted to explore possible

mechanisms of change.

Cue-reactivity. Because CERP focuses on reducing cue-triggered urges and internal

experiences, it can be argued that CERP works in part by reducing cue-reactivity. To test

this, we administered a paper/pencil cue-reactivity test before and after treatments (Snorrason

et al., 2015). However, the paper/pencil cue-reactivity manipulation failed to induce cue

reactivity in this sample. Plausible reason for why it did not work might be because in this

study all the phenomenology questionnaires were translated to Icelandic and therefore might

have been a slight difference in the cue itself. For future researches there is a reason to

speculate that using different types of cues (e.g. pictures of skin imperfection or coarse hairs)

might provoke stronger cue-reactivity. The sample size was also rather small so repeating the

cue-reactivity test again with larger sample size might work.

34

Because the cue-reactivity manipulation failed to induce significant cue-reactivity it

was decided to examine if self-report scales assessing wanting and liking skin picking/hair

pulling (Snorrason et al., 2015; Snorrason et al., 2017) would mediate treatment effects,

particularly in CERP. The results showed that reduction in liking (but not wanting) scores

were significantly correlated with change in symptom severity in HRT-CERP, but not HRT-

SC. These results suggest HRT-CERP may reduce symptoms by reducing liking or

pleasurable experiences associated with picking/pulling episodes.

Automatic versus focused behavior. In the study, six out of ten participants that

received HRT-SC were considered to be primarily focused in their pulling and picking

behavior, against only three in the HRT-CERP group. Even though these behavior styles tend

to co-occur within an individual (most people experience both styles to some extent),

clinicians have speculated that the difference styles might preferentially respond to different

treatment interventions (Flessner et al; 2008; Walter, Flessner, Conelea, & Woods; 2009). In

particular, it can be argued that CERP, and other interventions that address internal

experiences, would be more suitable for individuals with primarily focused behavior. In

contrast, for individuals were the behavior is primarily automatic, HRT-SC could be more

suitable because it emphasizes awareness training (Flessner et al; 2008). There were total of

nine participants with primarily focused behavior in the study but unfortunately the

randomization didn’t divide them equally into the two treatment groups. For that reason

interpretation about a possible role of different types of the behavior is difficult to determine.

Limitations

There were a few limitations in the present study. First, the sample may have differed

from the general population on some characteristics. All participants were women, university

student and 19 out of 20 were Caucasian. So our sample was rather homogeneous and may

not have adequately reflected the general SPD/HPD clinical population. Secondly, the sample

size was small, only 20 participants divided equally to both treatment groups. There was also

no waiting-list/no-treatment condition to control for natural influences. The clinical

symptoms of participants in this study were similar to other studies, but the severity may have

been lower, as expected in a university population. Finally, another important limitation is

that although interviewers were blind to the treatment conditions, they were not blind to the

purpose of the study.

35

Strengths

The study also had its strengths. As far as we know this is the first study to compare

the efficacy of HRT-CERP and HRT-SC as a treatment for HPD/SPD. Treatment was

implemented by trained psychotherapists who were supervised in weekly meetings. Also

multiple outcome measures were used to assess symptom improvement, including self-report

scales, clinical interviews and photograph ratings.

Conclusions

The main conclusion from this study is that both HRT-SC and HRT-CERP are

effective interventions to treat both HPD and SPD. The efficacy of HRT-SC is similar to

prior studies (e.g. Schuck, Keijsers, & Rinck, 2011; Teng, Woods, & Twohig, 2006) but as

mentioned before, this is the first controlled trial study with HRT- CERP as a treatment

protocol for HPD/SPD. These results advocate the application of HRT-CERP. It will be

interesting to see the result of the follow-up evaluation, and if there is a difference in relapse

rate between the two conditions. If our hypothesis is supported it will further support

implementing HRT-CERP as a treatment protocol for HPD and SPD.

The challenge for the future is to compare these behavioral interventions with sample

that is closer to the general population and with a larger treatment groups. We also believe

that four treatment sessions might have been too short of an intervention, at least for some of

our participants. Thus, a similar study with more treatment sessions would be interesting.

HRT-CERP might also be compared to other type of interventions like pharmacotherapy and

some combination of both treatments. Furthermore, future researches should attempt to gain

more insight into the mechanisms of change like the role of cue-reactivity.

36

References

Antony, M. M., Bieling, P. J., Cox, B. J., Enns, M. W., & Swinson, R. P. (1998).

Psychometric Properties of the 42-item and 21-item versions of the depression anxiety

stress scales in clinical groups and a community sample. Psychological Assessment, 10,

176-181. doi: 10.1037/1040-3590.10.2.176

American Psychiatric Association (2000). Diagnostic and statistical manual of mental

disorders (4th ed., Text Revision). Washington, DC: Author.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental

disorders (5th ed.). Washington, DC: Author.

Arnold, L. M., Auchenbach, M. B., & McElroy, S. L. (2001). Psychogenic excoriation. CNS

drugs, 15(5), 351-359. DOI: 10.2165/00023210-200115050-00002

Arnold, L., McElroy, S., Mutasim, D., Dwight, M., Lamerson, C, & Morris, E. (1998).

Characteristics of 34 adults with psychogenic excoration. Journal of Clinical Psychiatry,

59, 509-514.

Azrin, N. H. & Nunn, R. G. (1973). Habit-reversal: A method of eliminating nervous habits

and tics. Behaviour research and therapy, 11(4), 619-628. doi: 10.1016/0005-

7967(73)90119-8

Azrin, N. H., Nunn, R. G., & Frantz-Renshaw, S. E. (1982). Habit reversal vs negative

practice treatment of self-destructive oral habits (biting, chewing or licking of the lips,

cheeks, tongue or palate). Journal of Behavior Therapy and Experimental

Psychiatry, 13(1), 49-54. doi: 10.1016/0005-7916(82)90035-0

Bate, K. S., Malouff, J. M., Thorsteinsson, E. T., & Bhullar, N. (2011). The efficacy of habit

reversal therapy for tics, habit disorders, and stuttering: a meta-analytic review. Clinical

psychology review, 31(5), 865-871. doi: 10.1016/j.cpr.2011.03.013

Bienvenu, O. J.,Wang, Y., Shugart, Y. Y.,Welch, J.M., Grados,M. A., Fyer, A. J., et al.

(2009). Sapap3 and pathological grooming in humans: Results from the OCD

collaborative genetics study. American Journal of Medical Genetics. Part B,

Neuropsychiatric Genetics, 150B, 710–720. doi: 10.1002/ajmg.b.30897

Bloch, M. H., Landeros-Weisenberger, A., Dombrowski, P., Kelmendi, B., Wegner, R.,

Nudel, J., ... & Coric, V. (2007). Systematic review: pharmacological and behavioral

treatment for trichotillomania. Biological psychiatry, 62(8), 839-846. doi:

10.1016/j.biopsych.2007.05.019

Bohne, A., Keuthen, N., & Wilhelm, S. (2005). Pathological hair pulling, skin picking,

and nail biting. Annals of Clinical Psychiatry, 17, 227–232. doi:

10.1080/10401230500295354

37

Bohne, A., Wilhelm, S., Keuthen, N. J., Baer, L., & Jenike, M. A. (2002). Skin picking in

German students: prevalence, phenomenology, and associated characteristics. Behavior

Modification, 26(3), 320-339. doi: 10.1177/0145445502026003002

Boutelle, K.N., & Bouton, M.E. (2015). Implications of learning theory for developing

programs to decrease overating. Appetite, 93, 62-74. doi: 10.1016/j.appet.2015.05.013

Buhr, K., & Dugas, M. J. (2002). The intolerance of uncertainty scale: Psychometric

properties of the English version. Behaviour research and therapy, 40(8), 931-945. doi:

10.1016/S0005-7967(01)00092-4

Busner, J. og Targum, S. D. (2007). The clinical global impression scale: Applying a research

tool in clinical practice. Psychiatry, 4(7), 28-37. doi: 10.12691/ajmcr-3-10-1

Capriotti, M. R., Ely, L. J., Snorrason, I., & Woods, D. W. (2015). Acceptance-enhanced

behavior therapy for excoriation (skin-picking) disorder in adults: A clinical case

series. Cognitive and Behavioral Practice, 22(2), 230-239.

doi:10.1016/j.cbpra.2014.01.008

Christenson, G. A., Macenzie, T. B., & Mitchell, J. E. (1991). Characteristics of 60 adult

chronic hair pullers. The American journal of psychiatry, 148(3), 365. Retrieved from

https://search.proquest.com/docview/220485678?accountid=32710

Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2. Ed). Lawrence

Earlbaum Associates. Hillsdale, NJ, 20-26.

Coles, M.E., Frost, R.O., Heimberg, R.G., & Rheaume, J. (2003). “Not just right

experiences”: perfectionism, obsessive-compulsive features and general

psychopathology. Behaviour Research and Therapy, 41, 681-700. doi: 10.1016/S0005-

7967(02)00044-X

Conklin, C.A., & Tiffany, S.T. (2002). Applying extinction research and theory to cue-

exposure addiction treatments. Addiction, 97, 155-167 doi: 10.1046/j.1360-

0443.2002.00014.x

Diefenbach, G. J., Tolin, D. F., Crocetto, J., Maltby, N. og Hannan, S. (2005). Assessment of

trichotillomania: a psychometric evaluation of hair-pulling scales. Journal of

Psychopathology and Behavioral Assessment, 27, 169–178. doi: 10.1007/s10862-005-

0633-7

Diefenbach, G. J., Tolin, D. F., Hannan, S., Crocetto, J., & Worhunsky, P. (2005).

Trichotillomania: impact on psychosocial functioning and quality of life. Behaviour

research and therapy, 43(7), 869-884. doi: 10.1016/j.brat.2004.06.010

38

Diefenbach, G. J., Tolin, D. F., Meunier, S., & Worhunsky, P. (2008). Emotion regulation

and trichotillomania: A comparison of clinical and nonclinical hair pulling. Journal of

Behavior Therapy and Experimental Psychiatry, 39(1), 32-41. doi:

10.1016/j.jbtep.2006.09.002

Duke, D. C., Keeley, M. L., Geffken, G. R., & Storch, E. A. (2010). Trichotillomania: a

current review. Clinical Psychology Review, 30(2), 181-193. doi:

10.1016/j.cpr.2009.10.008

Duke, D. C., Keeley, M. L., Ricketts, E. J., Geffken, G. R., & Storch, E. A. (2010). The

phenomenology of hairpulling in college students. Journal of Psychopathology and

Behavioral Assessment, 32(2), 281-292. doi: 10.1007/s10862-009-9150-4

du Toit, P. L., van Kradenburg, J., Niehaus, D. J. H., & Stein, D. J. (2001). Characteristics

and phenomenology of hair-pulling: an exploration of subtypes. Comprehensive

Psychiatry, 42(3), 247-256. doi: 10.1053/comp.2001.23134

Flessner, C. A., Conelea, C. A., Woods, D. W., Franklin, M. E., Keuthen, N. J., & Cashin, S.

E. (2008). Styles of pulling in trichotillomania: exploring differences in symptom severity,

phenomenology, and functional impact. Behaviour Research and Therapy, 46(3), 345-357.

doi: 10.1016/j.brat.2007.12.009

Flessner, C. A., Penzel, F., Board, T. L. C. S. A., & Keuthen, N. J. (2010). Current treatment

practices for children and adults with trichotillomania: consensus among

experts. Cognitive and Behavioral Practice, 17(3), 290-300. doi:

10.1016/j.cbpra.2009.10.006

Flessner, C. A., Woods, D. W., Franklin, M. E., Cashin, S. E., Keuthen, N. J., & Board, T. L.

C. S. A. (2008). The Milwaukee inventory for subtypes of trichotillomania-adult version

(MIST-A): development of an instrument for the assessment of “focused” and “automatic”

hair pulling. Journal of Psychopathology and Behavioral Assessment, 30(1), 20-30. doi:

10.1007/s10862-007-9073-x

Freeston, M. H., Rhéaume, J., Letarte, H., Dugas, M. J., & Ladouceur, R. (1994). Why do

people worry?. Personality and individual differences, 17(6), 791-802.

doi:10.1016/0191-8869(94)90048-5

Grant, J. E., Levine, L., Kim, D., & Potenza, M. N. (2005). Impulse control disorders in

adult psychiatric inpatients. The American Journal of Psychiatry, 162, 2184–2188. doi:

10.1176/appi.ajp.162.11.2184

Grant, J. E., Stein, D. J., Woods, D. W., & Keuthen, N. J. (2012). Trichotillomania, skin

picking, and other body-focused repetitive behaviors. American Psychiatric Pub.

39

Grant, J. E., Williams, K. W., & Potenza, M. N. (2007). Impulse-control disorders in

adolescent psychiatric inpatients: Co-occurring disorders and sex differences. The Journal

of Clinical Psychiatry, 68, 1584–1594.

Griesemer, R. (1978). Emotionally triggered disease in a dermatologic practice. Adolescent

Phychiatry: Phychiatric Annals, 8(8) 49-56. doi: 10.3928/0048-5713-19780801-08

Guy W., & Bonato R., (1970). CGI: Clinical Global Impressions. In W. Guy & R. Bonato

(eds.) Manual for the ECDEU Assessment Battery 2 (p. 12-1 – 12-6). Chevy Chase, MD:

National Institute of Mental Health.

Havermans, R. C., & Jansen, A. T. (2003). Increasing the efficacy of cue exposure treatment

in preventing relapse of addictive behavior. Addictive behaviors, 28(5), 989-994. doi:

10.1016/S0306-4603(01)00289-1

Hoogduin, K., Verdellen, C., & Cath, D. (1997). Exposure and response prevention in the

treatment of Gilles de la Tourette's syndrome: four case studies. Clinical Psychology &

Psychotherapy, 4(2), 125-135. doi: 10.1002/(SICI)1099-0879(199706)4:2<125::AID-

CPP125>3.0.CO;2-Z

Ingimarsson, B. (2010). Próffræðilegt mat á DASS sjálfsmatskvarðanum. Þunglyndi, kvíði og

streita.

Jansen, A. (1998). A learning model of binge eating: cue reactivity and cue

exposure. Behaviour research and therapy, 36(3), 257-272. doi: 10.1016/S0005-

7967(98)00055-2

Javidim Z., Battersby, M., & Forbes, A. (2007). A case study of trichotillomania with social

phobia: Treatment and 4-year follow-up using cognitive-behaviour therapy. Behavior

Change, 24, 231-243. doi: 10.1375/bech.24.4.231

Keuthen, N., Deckersbach, T., Wilhelm, S., Hale, E., Fraim, C., Baer, L., & Jenike, M.

(2000). Repetive skin-picking in a student population and comparison eith a sample of

self-injurious skin pickers. Psychosomatics, 41, 210-215. doi: 10.1176/appi.psy.41.3.210

Keuthen, N.J., Rothbaum, B.O., Falkenstein, M.J., Meunier, S., Timpano, K.R., Timpano,

K.R… Welch, S.S (2011). DBT-enhanced habit reversal treatment for trichotillomania: 3-

and 6-month follow-up results. Depression and Anxiety, 28, 310-313. doi:

10.1002/da.20778

Keuthen, N. J., O’Sullivan, R. L., Ricciardi, J. N., Shera, D., Savage, C. R., Borgmann, A. S.,

... & Baer, L. (1995). The Massachusetts General Hospital (MGH) hairpulling scale: 1.

40

development and factor analyses. Psychotherapy and Psychosomatics, 64(3-4), 141-145.

doi: 10.1159/000289003

Lecrubier, Y., Sheehan, D. V., Weiller, E., Amorim, P., Bonora, I., Harnett Sheehan, K., ...

and Dunbar, G. C. (1997). The Mini International Neuropsychiatric Interview (MINI). A

short diagnostic structured interview: reliability and validity according to the CIDI.

European Psychiatry, 12, 224-231.

Lochner, C., Simeon, D., Niehaus, D. J., & Stein, D. J. (2002). Trichotillomania and skin

picking: A phenomenological comparison. Depression and Anxiety, 15, 83–86. doi:

10.1002/da.10034

Lootens, C. M., & Nelson-Gray, R. O. (2016). Treating trichotillomania: Successful

application of manualized cognitive-behavioral therapy. Clinical Case Studies, 15(5), 376-

391. doi: 10.1177/1534650116649438

Mansueto, C. S., Golomb, R. G., Thomas, A. M., & Stemberger, R. M. T. (2000). A

comprehensive model for behavioral treatment of trichotillomania. Cognitive and

Behavioral Practice, 6(1), 23-43. doi: 10.1016/S1077-7229(99)80038-8

Mansueto, C. S., Stemberger, R. M. T., Thomas, A. M., & Golomb, R. G. (1997).

Trichotillomania: A comprehensive behavioral model. Clinical Psychology Review, 17(5),

567-577. doi: 10.1016/S0272-7358(97)00028-7

Miltenberger, R. G. (2001). Habit reversal treatment manual for trichotillomania. Tic

Disorders, Trichotillomania, and Other Repetitive Behavior Disorders (pp. 171-195).

Springer US.

Monzani, B., Rijsdijk, F., Harris, J., & Mataix-Cols, D. (2014). The structure of genetic and

environmental risk factors for dimensional representations of DSM-5 obsessive-

compulsive spectrum disorders. JAMA psychiatry, 71(2), 182-189.

doi:10.1001/jamapsychiatry.2013.3524

Monzani, B., Rijsdijk, F., Cherkas, L., Harris, J., Keuthen, N., & Mataix‐Cols, D. (2012).

Prevalence and heritability of skin picking in an adult community sample: a twin

study. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 159(5),

605-610. doi: 10.1002/ajmg.b.32067

Moritz, S., Treszl, A., & Rufer, M. (2011). A randomized controlled trial of a novel self-help

technique for impulse control disorders: A study on nail-biting. Behavior

modification, 35(5), 468-485. doi: 10.1177/0145445511409395

41

Müller, A., Rein, K., Kollei, I., Jacobi, A., Rotter, A., Schütz, P., et al. (2011). Impulse

control disorders in psychiatric inpatients. Psychiatry Research, 15, 434–438. doi:

10.1016/j.psychres.2011.04.006

Novak, C. E., Keuthen,N. J., Stewart, S. E., & Pauls, D. L. (2009). A twin concordance study

of trichotillomania. American Journal of Medical Genetics Part B, 150B, 944–949. doi:

10.1002/ajmg.b.30922

Odlaug, B, & Grant, J. (2008). Trichotillomania and pathological skin picking: Clinical

comparison with an examination of comorbidity. Annals of Clinical Psychiatry, 20, 57-63.

Odlaug, B. L., Kim, S. W., & Grant, J. E. (2010). Quality of life and clinical severity in

pathological skin picking and trichotillomania. Journal of Anxiety Disorders, 24, 823–829.

doi:10.1016/j.janxdis.2010.06.004

Roos, A., Grant, J. E., Fouche, J.-P., Stein, D. J. & Lochner, C. (2015). A comparison of

brain volume and cortical thickness in excoriation (skin picking) disorder and

trichotillomania (hair pulling disorder) in women. Behavioural Brain Research, 279,

255–258. doi: 10.1016/j.bbr.2014.11.029

Schuck, K., Keijsers, G.P., & Rinck, M. (2011). The effects of brief cognitive-behaviour

therapy for pathological skin picking: A randomized comparison to wait-list control.

Behaviour Research and Therapy, 49, 11-17. doi: 10.1016/j.brat.2010.09.005

Sheehan, D. V., Lecrubier, Y., Sheehan, K. H., Janavs, J., Weiller, E., Keskiner, A., et al.

(1997). The validity of the Mini International Neuropsychiatric Interview (MINI)

according to the SCID-P and its reliability. European Psychiatry, 12, 232–241. doi:

10.1016/S0924-9338(97)83297-X

Shusterman, A., Feld, L., Baer, L., & Keuthen, N. (2009). Affective regulation in

trichotillomania: Evidence from a large-scale internet survey. Behaviour Research and

Therapy, 47, 637-644. doi: 10.1016/j.brat.2009.04.004

Sigurðsson, B.H. (2008). Samanburður á tveimur stöðluðum geðgreiningarviðtölum og

tveimur sjálfsmatskvörðum: MINI, CIDI, PHQ og DASS. (Unpublished dissertation).

University of Iceland, Reykjavík.

Snorrason, Í. (2008). Húðkroppunarárátta: Klínísk einkenni, tengsl við aðrar geðraskanir og

flokkun í DMS. Sálfræðiritið, 13, 9-26.

Snorrason, I., Belleau, E. L., & Woods, D. W. (2012). How related are hair pulling disorder

(trichotillomania) and skin picking disorder? A review of evidence for comorbidity,

similarities and shared etiology. Clinical Psychology Review, 32(7), 618-629. doi:

10.1016/j.cpr.2012.05.008

42

Snorrason, I., Belleau, E. L., & Lee, H.-J. (unpublished). Assessing excoriation (skin-picking)

disorder: development of a comprehensive diagnostic interview. University of

Wisconsin, Milwaukee.

Snorrason, I., Berlin, G. S., & Lee, H. J. (2015). Optimizing psychological interventions for

trichotillomania (hair-pulling disorder): an update on current empirical status. Psychology

Research and Behavior Management, 8, 105. doi: 10.2147/PRBM.S53977

Snorrason, Í., & Björgvinsson, Þ. (2012). Greining og meðferð hárplokkunar-og

húðkroppunaráráttu. Læknablaðið.

Snorrason, Í., & Ólafsson, R.P. (unpublished). Habit reversal meðferð við húðkroppunar- og

hárreytiröskun: handbók fyrir meðferðaraðila. Háskóli Íslands.

Snorrason, I., Olafsson, R.P., Flessner, C.A., Keuthen, N.J., Franklin, M.E., & Woods, D.W.

(2012). Skin Picking Scale-Revised: Factor structure and psychometric properties.

Journal of Obsessive-Compulsive and Related Disorders,1, 133-137.

doi: /10.1016/j.jocrd.2012.03.001

Snorrason, I., Olafsson, R. P., Houghton, D. C., Woods, D. W., & Lee, H. J. (2015).

‘Wanting’ and ‘liking’ skin picking: A validation of the Skin Picking Reward

Scale. Journal of behavioral addictions, 4(4), 250-260. doi: 10.1556/2006.4.2015.033

Snorrason, I., Ricketts, E.J.,. Olafsson, R.P., Houghton, D.C., Woods, D.W., & Piacentini, J.

(2017). Reward processing in trichotillomania: “Wanting” and “liking” hair pulling have

distinct correlates. Manuscript in preparation.

Snorrason, Í., Smári, J., & Ólafsson, R. P. (2009). Húðkroppunarárátta: Klínísk einkenni og

tengsl við geðræn vandamál í úrtaki háskólanema. Sálfræðiritið.

Snorrason, I., Smari, J., & Olafsson, R. P. (2010). Emotion regulation in pathological skin

picking: Findings from a non-treatment seeking sample. Journal of Behavior Therapy

and Experimental Psychiatry, 41, 238–245. doi: 10.1016/j.jbtep.2010.01.009

Snorrason, I., Smari, J., & Olafsson, R. P. (2011). Motor inhibition, reflection impulsivity

and trait impulsivity in pathological skin picking. Behavior Therapy, 42, 521–532. doi:

10.1016/j.beth.2010.12.002

Snorrason, I., & Woods, D. W. (2014). Hair pulling, skin picking, and other body-focused

repetitive behaviors. In E. A. Storch, & D. E. Mckay (Ed.), Obsessive-Compulsive

Disorders and its Spectrum; a Life-Span Approach (pp, 163-184). American

Psychological Association. doi: 10.1037/14323-009

43

Sulkowski, M.L., Jacob, M.L., & Storch, E.A. (2013). Exposure and response prevention and

habit reversal training: Commonalities, differential use, and combined applications.

Journal of Contemporary Psychotherapy, 43, 179-185. doi: 10.1007/s10879-013-9234-z

Tamam, L., Zengin, M., Karakus, G., & Ozturk, Z. (2008). Impulse control disorders in an

inpatient psychiatric unit of a university hospital. Klinik Psikofarmakiloji Bulteni, 18,

153–161.

Teng, E. J., Woods, D. W., Twohig, M. P., & Marcks, B. A. (2002). Body-focused repetitive

behavior problems: Prevalence in a nonreferred population and differences in perceived

somatic activity. Behavior Modification, 26, 340–360. doi:

10.1177/0145445502026003003

Teng, E. J., Woods, D. W. og Twohig, M. P. (2006). Habit Reversal as a treatment for

chronic skin picking: A pilot investigation. Behavior Modification, 30(4), 411-422. doi:

10.1177/0145445504265707

Tucker, B. T. P., Woods, D. W., Flessner, C. A., Franklin S. A., & Franklin M. E. (2011).

The skin picking impact project: phenomenology, interference and treatment utilization of

pathological skin picking in a population-based sample. Journal of Anxiety Disorders, 25,

88-95. doi: 10.1016/j.janxdis.2010.08.007

Twohig, M. P., & Woods, D. W. (2004). A preliminary investigation of acceptance and

commitment therapy and habit reversal as a treatment for trichotillomania. Behavior

Therapy, 35, 803-820. doi:10.1016/S0005-7894(04)80021-2

White, M. P., Shirer, W. R., Molfino, M. J., Tenison, C., Damoiseaux, J. S. & Greicius, M.

D. (2013). Disordered reward processing and functional connectivity in trichotillomania:

A pilot study. Journal of Psychiatry Research, 47, 1264–1272. doi:

10.1016/j.jpsychires.2013.05.014

Wilhelm, S., Keuthen, N. J., Deckersbach, T., Engelhard, I. M., Forker, A. E., Baer, L., ... &

Jenike, M. A. (1999). Self-injurious skin picking: clinical characteristics and

comorbidity. The Journal of Clinical Psychiatry, 60(7), 454-459.

Woods, D. W., Flessner, C., Franklin, M. E., Wetterneck, C. T., Walther, M. R., Anderson, E.

R., & Cardona, D. (2006). Understanding and treating trichotillomania: what we know and

what we don't know. Psychiatric Clinics of North America, 29(2), 487-501. doi:

10.1016/j.psc.2006.02.009

Woods, S. C., & Ramsay, D. S. (2000). Pavlovian influences over food and drug

intake. Behavioural Brain Research, 110(1), 175-182. doi: 10.1016/S0166-

4328(99)00194-1

44

Woods, D. W., Wetterneck, C. T., & Flessner, C. A. (2006). A controlled evaluation of

acceptance and commitment therapy plus habit reversal for trichotillomania. Behaviour

Research and Therapy, 44, 639-656. doi: 10.1016/j.brat.2005.05.006

45

Appendix

I

Table 1

Individual scores for each participant on both SPS-R/MGH-HS self-report scales and SPS-R-IV/MGH-

HS-IV clinical interview from before and after treatment

participants SPS-R/MGH-HS SPS-R-IV/MGH-HS-IV

Pre-assessment Post-assessment Pre-assessment Post-assessment

HPD

1 20 9 19 8

2 16 9 17 10

3 18 6 20 5

4 21 18 21 19

5 21 6 19 4

SPD

6 16 12 16 10

7 15 3 14 3

8 15 10 15 8

9 16 8 15 9

10 21 9 20 8

11 14 10 15 9

12 15 16 16 14

13 18 5 16 6

14 23 20 22 20

15 13 6 13 4

16 18 3 16 2

17 10 13 16 10

18 13 4 13 4

19 21 6 16 5

20 16 11 18 17

Note: Total score for MGH-HS/MGH-HS-IV is on the scale of 0-28. Total score for SPS-R/SPS-R-IV is

on the scale of 0-32.