Sensory over-responsivity in trichotillomania (hair-pulling disorder)

Author’s Accepted Manuscript Sensory over-responsivity in trichotillomania (hairpulling disorder) Martha J. Falkenstein, Christine A. Conelea, Lauryn E. Garner, David A.F. Haaga www.elsevier.com/locate/psychres

PII: DOI: Reference:

S0165-1781(16)32204-1 http://dx.doi.org/10.1016/j.psychres.2017.11.034 PSY10981

To appear in: Psychiatry Research Received date: 29 December 2016 Revised date: 7 October 2017 Accepted date: 10 November 2017 Cite this article as: Martha J. Falkenstein, Christine A. Conelea, Lauryn E. Garner and David A.F. Haaga, Sensory over-responsivity in trichotillomania (hair-pulling disorder), Psychiatry Research, http://dx.doi.org/10.1016/j.psychres.2017.11.034 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Sensory over-responsivity in trichotillomania (hair-pulling disorder) Martha J. Falkensteina*, Christine A. Coneleab, Lauryn E. Garnerc, and David A. F. Haagad a

b

McLean Hospital/Harvard Medical School, Belmont, MA, USA,

Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA, c

d

Department of Psychology, Fordham University, New York, NY, USA,

Department of Psychology, American University, Washington, DC, USA

*Corresponding author: Martha J. Falkenstein, Ph.D., McLean Hospital/Harvard Medical School, 115 Mill Street, Mail Stop #207, Belmont, MA 02478, Email: [email protected]

Abstract Objective: This study was an initial investigation of sensory-over responsivity (SOR) to external sensations among individuals with trichotillomania (TTM). Methods: Adults endorsing DSM-5 TTM criteria (N = 609) and a non-affected comparison sample (N = 268) completed a self-report survey. Results:

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The majority of the TTM group endorsed SOR symptoms; three-quarters endorsed at least mild tactile and auditory SOR. About 15% endorsed SOR symptoms in the severe to extreme range. TTM participants had significantly higher mean scores in both auditory (t (652.89) = -6.51, p <.001, d = 0.45) and tactile (t (655.24) = -8.38, p <.001, d = 0.58) modalities than comparison participants, with medium effect sizes. Greater levels of SOR were related to greater levels of perfectionism and by-proxy pulling urges. SOR was significantly and positively correlated with functional impairment when controlling for TTM severity. Conclusion: This study expands prior work in obsessive-compulsive related disorders by contributing the first data about associations between TTM and over-responsivity to external sensations. Findings collectively suggest SOR may be related to maladaptive emotion regulation processes in TTM. A novel measure of SOR was developed and administered in this study.

Keywords trichotillomania; hair pulling disorder; sensory over-responsivity; sensory intolerance

1. Introduction

1.1. SOR & OC-related disorders Sensory over-responsivity (SOR) has been described as a disproportionately intense, prolonged, or heightened reaction to ordinary sensory stimuli, such as tactile and auditory sensations (e.g., sound of people chewing, feeling of specific clothing textures) that leads to

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functional impairment (Rogers and Luby, 2011). Recent research has begun to examine relationships between sensory triggers, perfectionism, and OC-related disorders, and in particular how these may be related to SOR. SOR has been most frequently studied in association with autism spectrum disorder (ASD) and more recently obsessive-compulsive (OC)-related disorders. In ASD, SOR is a wellestablished construct and is part of DSM-5 criteria (American Psychiatric Association, 2013). SOR was brought to the attention of obsessive-compulsive disorder (OCD) researchers with Miguel and colleagues (2000), who proposed that “sensory phenomena,” already studied in Tourette’s syndrome (Bliss, 1980), may be a phenomenological characteristic worth investigating in individuals with OCD and Tourette’s syndrome, as it relates to “just-right” perceptions. Subsequent research included examination of the prevalence of sensory phenomena among 1001 adults with OCD by Ferrão and colleagues (2012), who found that 65% experienced sensory phenomena prior to performing compulsions. Hazen et al. (2008) described a case series of children presenting for treatment because of compulsions performed to alleviate SOR difficulties, despite a lack of typical OCD-related obsessions. In a cross-sectional study of parents and adult participants, Dar and colleagues (2012) showed large correlations between SOR, childhood ritualism, and adult OCD symptoms, leading the authors to speculate that oral and tactile hypersensitivity in children may lead to adult OCD in some cases. In a sample of children with anxiety, Conelea et al. (2014) found that SOR was more closely related to dimensional measures of OCD than other specific anxiety problems. These studies add to the growing body of literature indiciating that SOR is not specific to ASD and suggest that SOR may be a clinically important yet under recognized phenomenon in both pediatric and adult OCD.

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Misophonia, which has the literal meaning “hatred of sound” (Jastreboff and Jastreboff, 2002), is perhaps the most well-studied type of SOR. Schroder et al. (2013) described misophonia as potentially fitting into the DSM as an OC-related disorder due to similar clinical and functional characteristics. For example, Webber and colleagues (2014) described a case of pediatric misophonia in the context of comorbid OCD and Tourette syndrome and highlighted the functional similarities among these disorders, including a trigger of a negative emotion prompting repetitive behaviors to reduce distress. In another case report, an adolescent presenting with comorbid misophonia and OCD experienced a large reduction in misophonic symptoms after two sessions of exposure to distressing noises, the treatment indicated for OCD symtpoms (Reid et al., 2016). Misophonia has shown moderate correlations with OC, anxiety, and depressive symptoms in a sample of undergraduates (Wu et al., 2014). The first treatment study for a group of participants with misophonia was recently completed (Schröder et al., 2017), in which 90 patients with misophonia attended eight sessions of cognitive-behavioral therapy; 48% of these patients had significant decreases in their symptoms. 1.2. SOR & TTM Although these studies suggest possible links between SOR and OC-spectrum disorders, SOR has not yet been studied in trichotillomania (TTM; hair-pulling disorder, an OC-related disorder). There is a small literature that has examined sensitivity to internal somatic cues in TTM, specifically pain sensitivity, somatic activity, and somatic sensitivity (Blum et al., 2017; Teng et al., 2002; Woods et al., 1996). For instance, Blum and colleagues (2017) examined pain tolerance between adults with and without hair pulling; no relationship was found between pain tolerance and TTM symptom severity. Over-responsivity to external sensations has yet to be examined in TTM, and it would be useful to learn basic prevalence and descriptive

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phenomenolgical information within this population. There is wide variation among individuals with TTM in symptom presentation, and little is known about subtypes or endophenotypic variants, which could relate to treatment outcome, prognosis, and underlying genetic and neural vulnerabilities. Subtypes, or “styles,” of pulling have been proposed based on the degree to which an individual is aware of engaging in the pulling (e.g., Christenson and Mackenzie, 1994; Flessner et al., 2008) and the extent to which pulling is related to emotion regulation processes (e.g., Alexander et al., 2016; Diefenbach et al., 2008). Currently, we know there are largely two styles of pulling, “automatic” and “focused.” The sensory and affective aspects of these pulling styles are thought to differ. “Automatic” is characterized as a behavior that occurs outside of the puller’s awareness, whereas “focused” is believed to occur within conscious awareness and to function more as an emotion regulation strategy. “Focused” pulling has garnered particular attention in the treatment development literature (e.g., Keuthen et al., 2012; Woods et al., 2006) given that it may be less responsive to traditional habit reversal therapy (Azrin and Nunn, 1973). “Focused” pulling can often involve sensory triggers including tactile or visual sensations such as coarse hair, or the urge to pull hair to satisfy a need for symmetry, for example removing an eyebrow hair that seems out of place (e.g., Christenson and Mackenzie, 1994;), or with by-proxy urges to pull hair from other people that appear out of place (Falkenstein and Haaga, 2016). Byproxy urges have been associated with “focused” pulling and also perfectionism (Falkenstein and Haaga, 2016). Many hair pullers struggle with perfectionism as a trigger for pulling, and it has been found to be a useful treatment target for some (Mansueto et al., 1999; Pélissier and O’Connor, 2004). Whether “focused” pulling, SOR, and perfectionism are associated constructs in a sample with TTM remains unexamined. 1.3. SOR & perfectionism & NJREs

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Given that many individuals with OCD have an intolerance of experiences that are “Not Just Right” (NJREs) (e.g., Coles et al., 2003) or imperfect, which is similar to the triggers for many “focused” pulling episodes, it seems logical that perfectionism, NJREs, and SOR have been linked. Lee and colleagues (2009) compared adults with OCD and community controls on OCD symptoms, perfectionism, and “sensory phenomena” (defined as “uncomfortable sensations, feelings or perceptions that are focal or general in nature and can precede or accompany compulsions”). Sensory phenomena was significantly higher (68%) in OCD patients than controls (35%), and many dimensions of perfectionism and sensory phenomena were related, though they were shown to be separate concepts. NJREs have been associated with perfectionism among individuals with OCD (e.g., Coles et al., 2003; Moretz and McKay, 2009). Summers and colleagues (2014) examined NJREs in the context of visual, tactile, auditory modalities in an undergraduate sample. During tasks designed to invoke NJREs, NJREs were associated with the perfectionism dimensions of Organization and Doubts about Action, and they were experienced across the sensory modalities. 1.4. Current study In the current study, we aimed to determine whether hair pulling was related to overresponsivity to external sensations. We sought to learn about the prevalence of SOR among hair pullers in comparison to a non-affected sample, the type(s) of SOR experienced (i.e., whether tactile would be more common than auditory over-responsivity given the nature of hair pulling), associated impairment, and the relationships between SOR and TTM severity and also pulling style. Based on prior literature, we hypothesized that greater levels of SOR would be associated with greater levels of “focused” hair pulling, perfectionism, and TTM-by-proxy urges. 2. Method

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2.1. Participants The American University Institutional Review Board approved all study procedures. Participants with TTM (at least 18 years of age) were recruited for a study of “relationships and trichotillomania” through the Trichotillomania Learning Center, Inc. (TLC), a patient advocacy group, via their web page, Facebook page, and e-mail newsletters. The survey was available for two weeks in July 2014 and received 1109 responses. Excluded participants consisted of duplicates (n = 3), and participants who did not complete all measures of interest in the current study (n = 153). According to self-reported symptoms, 670 participants endorsed criteria consistent with DSM-5 TTM. We retained data from individuals who completed both the tactile and auditory SOR measures and therefore excluded n = 61, resulting in a final sample size of N = 609 for the current analyses. Of the 609 participants, the majority identified as female (96%), white (90%), and living in the United States (73%). For detailed demographic information, refer to Table 1. Non-affected comparison subjects were recruited from Amazon Mechanical Turk (MTurk) over the course of three weeks in August 2017 and were compensated $1.00 to $2.00. Following previously validated procedures (e.g., Shapiro et al., 2013), the survey was only advertised to MTurk users who had at least 90% approval ratings and who were current US residents. Interested users were directed to a link on Survey Monkey (which was different than the survey link and battery administered to the TTM sample) and then prompted to read a consent form and select whether they agreed to participate. Consistent with previous MTurk research (e.g., Behrend et al., 2011), participants who completed the survey in less than 60% of the projected time (n = 95) were excluded from analyses, as were participants who completed the survey with the same IP address more than once (n = 5). To ensure participants were adequate

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non-affected comparison subjects, subjects were excluded if they reported any lifetime psychiatric diagnoses or current TTM symptoms (n = 195) (as assessed by a score of 0 on the MGH-HPS) as was done in a previous study on MTurk (Ricketts et al., 2017). This resulted in an overall final non-affected comparison group sample of N = 268. 2.2. Measures Demographics Survey. For the TTM sample, the demographics questionnaire asked about age, age of TTM onset, race/ethnicity, country of origin, gender, and level of education. For the non-affected comparison group, the survey omitted the question about age of TTM onset and added a question about lifetime psychiatric diagnoses. Trichotillomania Diagnostic Interview-Revised for DSM-5, Self-Report Format (TDIDSM-5-Self). The TDI, originally a semi-structured interview (Rothbaum and Ninan, 1994), was modified for DSM-5 criteria and phrased in self-report format to assess eligibility. Each question mapped onto a question from the DSM-5 criteria for TTM (example, “Is your hair loss due to a medical problem other than trichotillomania, such as a dermatological condition?”) Massachusetts General Hospital Hairpulling Scale (MGH-HPS; Keuthen et al., 1995). The MGH-HPS is a self-report assessment of TTM severity during the preceding week, specifically assessing frequency of pulling, resistance to and control over pulling, and distress. Seven items are scored from 0 to 4, and total scores range from 0 to 28, such that higher scores represent greater severity. The MGH-HPS has shown good convergent and discriminant reliability, internal consistency and test-retest reliability (Keuthen et al., 1995; O’Sullivan et al., 1995).

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Trichotillomania-by-Proxy Scale (TTM-BP; Falkenstein and Haaga, unpublished measure). This self-report measure assesses TTM-by-Proxy symptoms and is adapted from the MGH-HPS. After responding to a screener question, “Have you ever had an urge to pull someone else's hair?” participants completed current (TTM-BP-C) and lifetime (TTM-BP-L) versions to assess current and past TTM-by-proxy symptoms. Items are rated from 0 to 4 with total scores ranging from 0 to 28, with higher scores indicating more severity. An example item is, “On an average day, how intense or "strong" were the urges to pull someone else's hair?” While this measure is nearly identical to the MGH-HPS in its structure and wording, its psychometric properties have not been examined. The Milwaukee Inventory for Subtypes of Trichotillomania-Adult Version (MIST-A; Flessner et al., 2008). The MIST-A is a self-report measure consisting of 15 items rated 0 to 9. Stronger endorsement of automatic and/or focused pulling is reflected by higher scores on automatic and focused subscales. Subscales have shown good internal consistency, construct validity, and discriminant validity between pulling styles. Frost Multidimensional Perfectionism Scale (FMPS; Frost et al., 1990). This self-report measure assesses the following 6 dimensions of perfectionism across 35 items: concern about making mistakes, setting high personal standards, perceived parental expectations, parental criticism, doubts about actions, and the tendency to be organized (the organization subscale is not in the total score). Each item is rated on a 5-point Likert scale. This scale has been found to have adequate reliability and validity (Frost et al., 1990).

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Sensory Over-Responsivity (SOR) Scales (SOR-Smell, SOR-Sight, SOR-Taste, SORHearing, & SOR-Touch (Falkenstein et al., unpublished measure). This unpublished measure (see Appendix for full measure) was used to assess overresponsivity to auditory, tactile, visual, olfactory, and gustatory stimuli and was adapted from a measure used with a general community sample in a survey study (Taylor et al., 2014). It consists of distress and impairment rating scales for both auditory and tactile over-responsivity. The SOR Scales each contain 4 questions rated on a scale from 0 to 4, with total overall scores ranging from 0 to 80. Total scores for each subscale are separate and range from 0 through 16, with higher scores indicating greater severity. All SOR Scales were administered to all nonaffected comparison subjects, and only the SOR-Hearing and SOR-Touch scales were administered to TTM participants due to development of the complete SOR Scales occurring after completion of the study of TTM participants. Psychometric properties of this measure are reported below in the Results section. Amsterdam Misophonia Scale (A-MISO-S; Schröder et al., 2013). Six items are rated from 0 to 4, and overall severity scores range from 0 to 24. Psychometric properties of this scale area currently unknown. Misophonic scores are considered subclinical from 0-4, mild from 5-9, moderate 10-14, severe 15-19, and extreme 20-24. Misophonia Questionnaire (MQ; Wu et al., 2014). The MQ is a self-report questionnaire assessing misophonia and related emotions and behaviors. The first section measures the presence of specific misophonic experiences, the second assesses emotional and behavioral reactions to misophonia triggers, and the third is a rating scale of overall sound sensitivity. We utilized the total score, which is obtained from summing the first two sections to yield possible total scores ranging from 0 to 68.

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Sensory Over-Responsivity Inventory (SensOR; Schoen et al., 2008). The SensOR was originally designed as a parent-report measure. The version used by Conelea and colleagues (2014) was administered, and items were re-worded to a self-report format. This scale is 52 items, 30 of which pertain to tactile sensations, and 22 to auditory sensations. Each sensation is rated as either bothersome or not (“Yes” or “No”) and summed for a total score (ranging from 0 to 52). Each sensation endorsed as bothersome is then rated for associated distress and avoidance, on 0 to 5 scale. Mean distress and avoidance scores are calculated from all items. In Conelea et al. (2014), internal consistency was strong, with moderate correlations between the tactile and auditory subscales. Sheehan Disability Scale (SDS; Sheehan, 1983). The SDS is a 3-item self-report measure of disability in family life/home, work, and social settings. Responses are provided on a 10-point Likert scale, with higher scores indicating greater disability. An overall perceived disability score can range from 3 to 30. The SDS has shown strong reliability and validity (Leon et al., 1992). Depression and Anxiety Stress Scales - 21 (DASS-21; Lovibond and Lovibond, 1995). Depression and anxiety were assessed with the 7-item subscales of the DASS; higher scores indicate greater symptomatology. Subscales have good convergent and discriminant validity (Antony et al., 1998; Lovibond and Lovibond, 1995) as well as internal consistency with both clinical (Brown et al., 1997) and non-clinical samples (Henry and Crawford, 2005). Open-Ended Qualitative Data. Participants were asked to provide open-ended qualitative descriptions about their experiences with SOR, in hopes of these responses allowing us to better understand SOR phenomenology.

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2.3. Procedure Interested TTM participants were directed from Trichotillomania Learning Center advertisements, and interested non-affected comparison participants were directed from MTurk to the informed consent, which was a requirement before proceeding to the survey. The survey was administered through surveymonkey.com (Finley and Finley, 1999). For the TTM sample, the measures were part of a larger survey about interpersonal relationship functioning (Falkenstein and Haaga, 2016). 2.4. Data analysis All tests were conducted using the Statistical Package for the Social Sciences (SPSS, version 19). Prior to analyses, it was confirmed that all statistical assumptions were met; Levene’s test was used to evaluate equality of variance. All tests of significance were two-tailed. We used a Bonferroni correction in order to control familywise Type I error rates, by considering categories of variables as each family of hypotheses tested (psychometric tests, group differences between TTM and comparison sample, associations with TTM, impairment, perfectionism, and by-proxy pulling), thus the corrected alpha is 0.01 (0.05/6), given these six categories of tests. We examined associations between SOR symptoms and clinical and demographic factors using bivariate correlations. Partial correlations were used to analyze potential associations between SOR and impairment and also when examining discriminant validity between SOR and measures of other constructs, controlling for TTM severity. Steiger’s z test for dependent correlations was used to compare magnitudes of correlations (Meng et al., 1992). Independent samples t-tests were used to compare group differences in SOR scores between the TTM sample and nonaffected comparison sample, as well as individuals with and without TTM-by-proxy urges within the TTM sample.

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3. Results 3.1. Psychometric properties of the SOR-Scales Cronbach’s alpha was calculated to assess the internal consistency of the SOR Scales and its subscales. In the non-affected comparison sample, the SOR Scales demonstrated strong internal consistency (Cronbach’s α = 0.93), as did the subscales, SOR-Hearing (0.89), SORTouch (0.88), SOR-Smell (0.90), SOR-Sight (0.94), and SOR-Taste (0.88). All five subscales were positively intercorrelated (see Table 2). In the TTM sample, both the SOR-Hearing (0.92) and SOR-Touch (0.89) scales demonstrated excellent internal consistency. These two subscales were positively intercorrelated (r = 0.462, p < .001). We tested convergent and discriminant validity by examining correlations between the SOR-Scales and the SensOR, Amsterdam Misophonia Questionnaire, Misophonia Questionnaire, and DASS Depression and Anxiety subscales. For convergent validity, the SOR-Scales total score (sum of SOR-Hearing, Touch, Smell, Sight, and Taste Scales) had a large correlation with the SensOR total score (r = 0.55, p <.001). The SOR-Hearing scale also had large correlations with the Amsterdam Misophonia Scale (r = 0.56, p < .001) and Misophonia Questionnaire (r = 0.59, p <.001). We also conducted partial correlations to control for depression and anxiety within these correlations. The SOR-Scales total score maintained a large correlation with the SensOR total score (pr = 0.49, p < .001), and SOR-Hearing scale with the Amsterdam Misophonia Scale (pr = 0.53, p <.001) and Misophonia Questionnaire (r = 0.56, p <.001). Regarding discriminant validity, the SOR-Scales total score had small to medium correlations with the DASS Anxiety subscale (r = 0.32, p <.001) and DASS Depression subscale (r = 0.22, p < .001). When comparing the correlations between the SOR-Scales and SensOR and the SORScales and DASS Depression, they are significantly different (Z = 5.23, p <.001), as are the

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correlations between SOR-Scales and SensOR and SOR Scales and DASS Anxiety (Z = 3.90, p <.001). 3.2 SOR Symptomatology SOR Scales. In the TTM sample, mean scores on both the SOR-Touch and SOR-Hearing subscales were suggestive of overall mild SOR symptomatology, although a wide range of scores was observed (see Table 1 for descriptive data). On the SOR-Touch, TTM participants had significantly higher mean scores (M = 4.47, SD = 3.69) than non-affected participants (M = 2.55, SD = 2.83) with a medium effect size (t (655.24) = -8.38, p <.001, d = 0.58). Regarding severity (as measured by question #1 on each SOR scale), on the SOR-Touch, 22% of TTM participants endorsed Not at all, 64% Mild to Moderate, and 13% Severe to Extreme. In the non-affected comparison sample, 42% of participants endorsed Not at all, 53% Mild to Moderate, and 6% Severe to Extreme. On the SOR-Hearing, TTM participants had significantly higher mean scores (M = 4.29, SD = 3.84) than non-affected participants (M = 2.74, SD = 2.96) with a medium effect size (t (652.89) = -6.51, p <.001, d = 0.45). For severity on the SOR-Hearing, 26% of TTM participants endorsed Not at all, 58% Mild to Moderate and 15% Severe to Extreme. In the non-affected comparison sample, 38% of participants endorsed Not at all, 55% Mild to Moderate, and 6% Severe to Extreme. To assess whether gender distribution across the samples affected the results given that 96% of the TTM sample was female, we conducted a secondary analysis in which we examined the descriptives for SOR-Hearing and SOR-Touch in a sample of 100% female non-affected comparison participants and 100% female TTM participants. The results were maintained: on the SOR-Hearing, TTM participants had significantly higher mean scores (M = 4.32, SD = 3.83)

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than non-affected participants (M = 2.95, SD = 3.04) with a medium effect size (t (288.68) = 4.62, p <.001, d = 0.40), and on the SOR-Touch, TTM participants had significantly higher mean scores (M = 4.54, SD = 3.68) than non-affected participants (M = 3.07, SD = 2.98) with a medium effect size (t (282.76) = -5.09, p <.001, d = 0.44). 3.3. Associations between SOR and hair pulling within the TTM sample. Small correlations were found between SOR and TTM severity. Specifically, there was a small, significant correlation between MGH-HPS and SOR-Touch (r = 0.19, p < .001) and a small, nonsignificant correlation between MGH-HPS and SOR-Hearing scores (r = 0.08, p = .06). Correlations between SOR and hair pulling style were small to medium between SOR-Touch and MIST-Automatic (r = 0.19 , p <.001) and MIST-Focused (r = 0.23 , p <.001). There was a small, non-significant correlation between SOR-Hearing and MIST-Automatic scores (r = 0.07, p = .08) and a small, significant correlation between SOR-Hearing and MIST-Focused scores (r = 0.18, p <.001). Differences in correlations between MIST-Automatic and MIST-Focused with and SOR-Touch were not significant (Z = 0.78, p = 0.44), however differences in correlations between MIST-Automatic and MIST-Focused with SOR-Hearing were significant (Z = 2.03, p = 0.04) in unadjusted analyses, though non-significant with Bonferroni correction. 3.4. SOR and impairment in the TTM sample. In a partial correlation controlling for MGH-HPS severity, the SDS and the SOR-Hearing scale had a small-to-medium sized correlation of pr = 0.190, p < .001, and SDS and SOR-Touch scale had a medium-sized correlation of pr = 0.274, p < .001. Thus, SOR was positively associated with impairment, even when controlling for hair pulling symptom severity. Participants also opted-in to provide qualitative data for this survey about their SOR experiences in general. Several participants described the impact of SOR on their lives, illustrating how impairing SOR can be. One

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participant wrote about tactile over-responsivity, “My tactile discomfort lies in how I feel in clothes. They always feel too tight and uncomfortable as soon as I step out of the house. For this reason, I only go out when absolutely necessary (school or work).” Another participant described tactile over-responsivity, “I have problems with clothes that are very clingy, tight or form fitting...including sports bras and body shapers. I do not wear anything that is tight or even mildly snug. I get very irritated, panicked and can sometimes have a full on panic attack.” Participants also described experiences with auditory over-responsivity, including, “I cannot fall asleep if I hear a clock ticking, or a tap leaking. I have to shout louder than the sound the dishes make when I'm arranging them in the cupboard. I scream or cover my ears if a truck or a bus passes by me.” And another participant stated, “When there is fire alarm testing at work, I have to leave for the day or I get almost zero work done if I stay.” With regard to how SOR relates to TTM, one participant described, “The texture of mascara increases my urge to pull.” A second participant wrote, “I have more issues with brittle or rough textures triggering my desire to pull. Loose strings or anything I can snap into pieces are more distracting. I do not mind slippery or greasy textures.” 3.5. Associations between SOR and perfectionism in the TTM sample. There were medium, significant correlations between SOR and various dimensions of perfectionism, including the FMPS total score and SOR-Touch (r = 0.272 , p <.001), and SOR-Hearing (r = 0.256, p <.001). Among the dimensions of perfectionism, the strongest correlation was between the Doubts about Actions subscale and SOR-Touch (r = 0.382, p = <.001) and SOR-Hearing (r = .331, p <.001) and also the Concern over Mistakes subscale and SOR-Touch (r = 0.287, p = <.001) and SOR-Hearing (r = .245, p <.001). Correlations with the other subscales were small or non-significant (see Table 3).

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3.6. Associations between SOR and hair pulling by proxy. In unadjusted analyses, TTM participants who endorsed having TTM-BP urges had higher mean SOR-Touch scores (M = 4.77, SD = 3.68) than participants who did not endorse TTM-BP urges, with minor effect (M = 4.12, SD = 3.67) (t (607) = 2.17, p = .03., d = 0.02). Following Bonferroni adjustment, these results are not significant. Participants with TTM-BP urges had higher SOR-Hearing scores (M = 4.70, SD = 3.92) than participants who did not endorse TTM-BP urges, with small effect (M = 3.81, SD = 3.69) (t (607) = 2.86, p = .004, d = 0.23). 4. Discussion TTM is recognized to be a heterogeneous disorder, yet clinically meaningful subtypes remain poorly defined due in part to limited understanding of the relationship between specific pulling “styles” and sensory and affective experiences. The current study is the first to examine the relationship between hair pulling and sensory over responsivity (SOR) to external sensations, an atypical sensory-affective experience that has been implicated in other OC-spectrum disorders. Symptoms of SOR were very common in a large sample of adults with self-reported hair pulling: 77% endorsed at least mild tactile symptoms and 73% at least mild auditory SOR (in contrast with the non-affected comparison group: 59% endorsed at least mild tactile symptoms, and 61% at least mild auditory). A sizeable portion of the TTM sample reported SOR symptoms in the severe to extreme range (15% in the tactile domain, 13% in auditory domain), with many fewer endorsing this severity range in the non-affected comparison group (6% for both tactile and auditory). Mean scores on the SOR scales measuring auditory and tactile SOR symptoms were significantly higher in the TTM sample than the non-affected comparison sample, with medium effect. Results generally confirmed our hypothesis that greater levels of SOR were related to greater levels of “focused” hair pulling, perfectionism, and TTM-by-proxy

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urges. There was a positive correlation found between SOR and functional impairment after controlling for hair pulling symptom severity. This overall pattern of results suggests that SOR symptoms may be more relevant to TTM subtypes characterized by maladaptive emotion regulation, such “focused” or “internal-regulating” pulling, as compared to a subtype characterized as habitual in nature (“automatic” or “low awareness” pulling (Alexander et al., 2016; Roberts et al., 2013). The observed high rate of SOR endorsement by the TTM sample is consistent with prior research suggesting that adults with OC-related phenomena have a greater tendency to report SOR symptoms than adults without OC-phenomena (Taylor et al., 2014). However, high rates of SOR have also been reported in samples with non-OC spectrum disorders, such as autism (Rogers and Ozonoff, 2005), anxiety (Conelea et al., 2014), and ADHD (Ben-Sasson et al., 2014). More research is needed to determine whether SOR is best conceptualized as a distinct OC-spectrum disorder, a phenomenological characteristic of one or more existing diagnoses that is not yet described in current nosology, or a transdiagnostic construct that cuts across multiple forms of psychopathology (i.e., is synonymous to the “sensory reactivity” element of the National Institute of Mental Health’s Research Domain Criteria (RDoC)’s “arousal” construct (RDoC website: http://www.nimh.nih.gov/research-priorities/rdoc/index.shtml). Our analyses examining the relationships between SOR, TTM symptomatology, perfectionism, and functional impairment preliminarily suggest the possibility that SOR may be related to aberrant emotion regulation processes in TTM. The emotion regulation model of TTM proposes that hair pulling functions as a maladaptive emotion regulation strategy in those who experience chronically high levels of emotional arousal, heightened emotional reactivity, and a fundamental deficit in healthy emotion regulation (Penzel, 2003; Shusterman, et al., 2009) This

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model is thought to be particularly applicable to the “focused” or “internal-regulating” style of pulling, in which the act of pulling provides relief, avoidance, or escape from negative emotions (Roberts et al., 2013). Several findings support this potential link to emotion regulation. First, SOR severity was significantly and positively correlated with various domains of perfectionism. Perfectionism has been linked to emotion regulation, such that maladaptive perfectionism is associated with greater psychological distress (Aldea and Rice, 2006), self-harm behaviors (Chester et al., 2015), and chronic stress (Richardson et al., 2014). Second, SOR severity in both the auditory and tactile domains was significantly and positively correlated with global functional impairment when controlling for hair pulling severity, suggesting that SOR symptoms uniquely contribute to functional impairment in those with TTM. However, it is important to note that data do not definitively implicate a specific relationship between SOR and focused pulling (vs. automatic), and there remains the possibility that relationships found between SOR and perfectionism are attributable to a third unmeasured variable (e.g., comorbid psychopathology). Although the current data do not enable us to examine precisely how or why SOR may be linked to emotion regulation deficits in TTM, there are several possibilities worth investigating in future research. It is possible that SOR is another phenotypic expression of a core emotion regulation deficit that underlies the syndrome. There is some evidence that SOR does not result from altered peripheral sensory perception but is instead an altered affective or subjective appraisal of sensory input. For example, adults with tics reported subjectively higher sensory sensitivity and distress than controls but did not show abnormalities in the threshold of detection for auditory and tactile stimuli (Belluscio et al., 2011). It is also possible that SOR symptoms contribute to high levels of emotional arousal, which in turn increases the likelihood of engaging

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in hair pulling as an emotion regulation strategy. SOR symptoms may also be more directly functionally related to pulling, as is illustrated by our participants’ qualitative descriptions of sensory stimuli that elicit the urge to pull. Finally, it may be the case that a shared underlying neuropathology underlies both TTM and SOR; abnormalities in cortico-subcortical circuitry involved in emotion regulation, emotional processing, inhibitory control, and memory processing have been implicated in both conditions (Odlaug et al., 2014; Koziol et al., 2011). Another notable finding was that those with TTM-by-proxy pulling urges had higher SOR tactile and auditory severity scores (with Bonferroni correction, this difference was only significant for auditory scores). TTM-by-proxy is a very understudied construct, having been described in only one study (using the same sample as the current sample; Falkenstein and Haaga, 2016) and a brief case report (Beattie et al., 2009). Therefore, it is unclear whether TTMby-proxy urges are also related to emotional processing deficits. It may also be possible that SOR and TTM-by-proxy urges are different variants of NJREs in that both experiences can involve an external sensory stimulus that elicits a vague sense of somatic discomfort or incompleteness, the removal of which is negatively reinforced by repetitive behaviors (e.g., repeatedly adjusting clothing in the case of tactile SOR or by-proxy pulling in TTM, both aimed at achieving a “just right” feeling). The current study has several limitations to note. Given that the study was administered in a self-report, online format, TTM diagnostic status was not confirmed by a clinician. Several prior studies have utilized online sampling to study TTM (e.g., Flessner et al., 2008) and SOR phenomenology (Taylor et al., 2014). Findings may have been influenced by our ability to measure SOR symptoms. The measure of SOR used in the current study is novel, and it has not been administered independent of this work. There is currently no gold-standard, empirically

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validated assessment tool for measuring SOR. For example, one widely used tool, the Sensory Profile (Dunn, 1999), measures a broad array of sensory processing patterns (e.g., sensation seeking, registration) and discriminant validity has not been well tested in psychiatric populations. We decided to validate our measure SOR against other measures of SOR which are face valid for this reason, and additionally, we chose to expand upon the questionnaire used in Taylor et al. (2014) by including questions related to SOR-related distress and impairment as well as adding additional sensory modalities (Taylor et al. only measured tactile and auditory symptoms). A limitation of the measures we chose is that the SensOR was developed for parents, and ours was used for adults rating their own experiences. Future psychometric testing of this measure, particularly in samples of controls and other clinical populations, will be important in furthering this line of research. It will also be important for future research to examine differences between subjective ratings of SOR symptoms and objective measures of sensory sensitivity. Another limitation of these findings was that only auditory and tactile sensory modalities were assessed in the TTM sample; future work should administer the other SOR Scales in a TTM sample to learn about SOR in other modalities. Finally, the current study did not assess for the presence of other psychopathology that has been shown to be related to sensory problems, such as autism spectrum disorders and ADHD. 4.1. Conclusion There are many important implications of these findings. First, the associations found between SOR and hair pulling severity, pulling style, and perfectionism add to the body of evidence that sensory over-responsivity may be related to OC-spectrum conditions, though several questions remain about this relationship. For instance, one question for future study is whether individuals with both TTM and SOR comprise a specific endophenotype which would

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benefit from a different treatment approach than is indicated for TTM alone. This information may be useful in a personalized medicine approach that aims to tailor intervention to an individuals’ unique characteristics. Additional questions for further study include whether SOR is an OC-spectrum disorder which we have ignored in our nosology, and whether SOR in TTM is related to NJREs in OCD, as this may be a transdiagnostic construct among OC-related disorders. The implications of our findings extend to clinical work as well. The TTM sample endorsed a significantly higher level of SOR auditory and tactile symptoms than the non-affected comparison sample, with a medium effect size. This was correlated with impairment, controlling for symptom severity. This suggests the importance of assessing SOR as part of clinicians’ functional analyses of hair pulling, with the possible integration of interventions targeting the sensory modality, as is utilized in Comprehensive Behavioral Treatment (ComB) for TTM (Falkenstein et al., 2016; Mansueto et al., 1997; Mansueto et al., 1999). There are currently no empirically supported treatments for SOR, and it is unclear which techniques may be most useful. Interventions reported in case studies have utilized exposure (e.g., McGuire et al., 2015; Reid et al., 2016), but if SOR is indeed related to emotion regulation deficits, other viable candidate treatments could be interventions targeting distress tolerance/emotion regulation. Future research should focus on clarifying the role of SOR in TTM and more broadly, the role of SOR within OC-related disorders as a whole, with the ultimate goal of improving conceptualization and treatment options for these impairing phenomena.

Acknowledgements The authors wish to thank Leslie Rubin and Mathew Stewart for their assistance with data analysis.

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Funding The research was supported by the College of Arts and Sciences at American University.

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Appendix: SOR-Scales SOR-Touch The following questions are about tactile sensations that you may or not feel bothered by, such as clothing textures or tightness; substances that feel sticky, greasy, or wet; or activities like haircuts or cutting nails. 1) How much have sensations like these bothered you (or made you uncomfortable)? 0 = Not at all bothered 1 = Mildly bothered (not too noticeable) 2 = Moderately bothered (noticeable, but still able to ignore it if I try) 3 = Severely bothered (very noticeable, difficult to focus on anything else) 4 = Extremely bothered (overwhelming, impossible to focus on anything else) 2) How often have you avoided certain places, situations, or activities because of not wanting to encounter tactile sensations like these? When you think about your answer to this question, also include ways you have modified activities or your behavior (e.g., wore only clothing that was comfortable, asked someone else to do a task for you, such as cooking with sticky, greasy, or wet substances). 0 = Never 1 = Rarely (occasional avoidance. Little or no modification of my lifestyle) 2 = Sometimes (noticeable avoidance but still manageable. Only some modification of my lifestyle, no major changes) 3 = Often (extensive avoidance. Significant modification of my lifestyle - it was difficult to manage my usual activities or relied a lot on other people to do things for me) 4 = Always (overwhelming or constant avoidance. Extensive modification of my lifestyle - I was not able to do important activities I needed to do on my own) 3) How much has the discomfort caused by tactile sensations like these interfered with your ability to work or perform your responsibilities at home? 0 = No interference 1 = Slight interference (little or no difficulty, could do most tasks I needed to do) 2 = Significant interference (some difficulty, I still managed to do most things if I tried) 3 = Substantial impairment (significant difficulty, there were many things I couldn’t do because of sensory discomfort) 4 = Extreme, incapacitating impairment (extensive difficulty, unable to manage important tasks because of sensory discomfort) 4) How much has the discomfort caused by tactile sensations like these interfered with your social activities? 0 = No interference 1 = Slight interference (little or no impact on my social life) 2 = Significant interference (some impact, I still managed to do most things if I tried) 3 = Substantial impairment (significant impact, there were many things I couldn’t do) 4 = Extreme, incapacitating impairment (extensive impact, unable to socialize)

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SOR-Hearing The following questions are about certain auditory sensations that you may or not feel bothered by, such as the sound of alarms, sirens, appliances, or background noises like people talking or ticking clocks. 1) How much have these sensations bothered you (or made you uncomfortable)? 0 = Not at all bothered 1 = Mildly bothered (not too noticeable) 2 = Moderately bothered (noticeable, but still able to ignore it if I try) 3 = Severely bothered (very noticeable, difficult to focus on anything else) 4 = Extremely bothered (overwhelming, impossible to focus on anything else) 2) How often have you avoided certain places, situations, or activities because of not wanting to encounter auditory sensations like these? When you think about your answer to this question, also include ways you have modified activities or your behavior (e.g., wore earplugs or covered your ears, asked someone else to do a task for you, like vacuum). 0 = Never 1 = Rarely (occasional avoidance. Little or no modification of my lifestyle) 2 = Sometimes (noticeable avoidance but still manageable. Only some modification of my lifestyle, no major changes) 3 = Often (extensive avoidance. Significant modification of my lifestyle - it was difficult to manage my usual activities or relied a lot on other people to do things for me) 4 = Always (overwhelming or constant avoidance. Extensive modification of my lifestyle - I was not able to do important activities I needed to do on my own) 3) How much has the discomfort caused by auditory sensations like these interfered with your ability to work or perform your responsibilities at home? 0 = No interference 1 = Slight interference (little or no difficulty, could do most tasks I needed to do) 2 = Significant interference (some difficulty, I still managed to do most things if I tried) 3 = Substantial impairment (significant difficulty, there were many things I couldn’t do because of sensory discomfort) 4 = Extreme, incapacitating impairment (extensive difficulty, unable to manage important tasks because of sensory discomfort) 4) How much has the discomfort caused by auditory sensations like these interfered with your social activities? 0 = No interference 1 = Slight interference (little or no impact on my social life) 2 = Significant interference (some impact, I still managed to do most things if I tried) 3 = Substantial impairment (significant impact, there were many things I couldn’t do) 4 = Extreme, incapacitating impairment (extensive impact, unable to socialize)

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SOR-Smell The following questions are about olfactory sensations (smells) that you may or not feel bothered by, such as smells including certain food items, cologne/perfume, body odor, flowers, or soap. 1) How much have sensations like these bothered you (or made you uncomfortable)? 0 = Not at all bothered 1 = Mildly bothered (not too noticeable) 2 = Moderately bothered (noticeable, but still able to ignore it if I try) 3 = Severely bothered (very noticeable, difficult to focus on anything else) 4 = Extremely bothered (overwhelming, impossible to focus on anything else) 2) How often have you avoided certain places, situations, or activities because of not wanting to encounter smell sensations like these? Include ways you have modified activities or your behavior (e.g., avoided being around flowers, perfume/cologne/soap, asked someone else to do a task for you, such as cooking food with a certain odor). 0 = Never 1 = Rarely (occasional avoidance. Little or no modification of my lifestyle) 2 = Sometimes (noticeable avoidance but still manageable. Only some modification of my lifestyle, no major changes) 3 = Often (extensive avoidance. Significant modification of my lifestyle - it was difficult to manage my usual activities or relied a lot on other people to do things for me) 4 = Always (overwhelming or constant avoidance. Extensive modification of my lifestyle - I was not able to do important activities I needed to do on my own) 3) How much has the discomfort caused by smell sensations like these interfered with your ability to work or perform your responsibilities at home? 0 = No interference 1 = Slight interference (little or no difficulty, could do most tasks I needed to do) 2 = Significant interference (some difficulty, I still managed to do most things if I tried) 3 = Substantial impairment (significant difficulty, there were many things I couldn’t do because of sensory discomfort) 4 = Extreme, incapacitating impairment (extensive difficulty, unable to manage important tasks because of sensory discomfort) 4) How much has the discomfort caused by smell sensations like these interfered with your social activities? 0 = No interference 1 = Slight interference (little or no impact on my social life) 2 = Significant interference (some impact, I still managed to do most things if I tried) 3 = Substantial impairment (significant impact, there were many things I couldn’t do) 4 = Extreme, incapacitating impairment (extensive impact, unable to socialize)

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SOR-Sight The following questions are about visual sensations that you may or not feel bothered by, such as things looking out of place, sensitivity to light, or the look of certain colors or patterns. 1) How much have sensations like these bothered you (or made you uncomfortable)? 0 = Not at all bothered 1 = Mildly bothered (not too noticeable) 2 = Moderately bothered (noticeable, but still able to ignore it if I try) 3 = Severely bothered (very noticeable, difficult to focus on anything else) 4 = Extremely bothered (overwhelming, impossible to focus on anything else) 2) How often have you avoided certain places, situations, or activities because of not wanting to encounter visual sensations like these? Include ways you have modified activities or your behavior (e.g., stayed out of bright light, removed things that looked out of place or distracting, asked someone else to do a task for you, such as fix the way something looked). 0 = Never 1 = Rarely (occasional avoidance. Little or no modification of my lifestyle) 2 = Sometimes (noticeable avoidance but still manageable. Only some modification of my lifestyle, no major changes) 3 = Often (extensive avoidance. Significant modification of my lifestyle - it was difficult to manage my usual activities or relied a lot on other people to do things for me) 4 = Always (overwhelming or constant avoidance. Extensive modification of my lifestyle - I was not able to do important activities I needed to do on my own) 3) How much has the discomfort caused by visual sensations like these interfered with your ability to work or perform your responsibilities at home? 0 = No interference 1 = Slight interference (little or no difficulty, could do most tasks I needed to do) 2 = Significant interference (some difficulty, I still managed to do most things if I tried) 3 = Substantial impairment (significant difficulty, there were many things I couldn’t do because of sensory discomfort) 4 = Extreme, incapacitating impairment (extensive difficulty, unable to manage important tasks because of sensory discomfort) 4) How much has the discomfort caused by visual sensations like these interfered with your social activities? 0 = No interference 1 = Slight interference (little or no impact on my social life) 2 = Significant interference (some impact, I still managed to do most things if I tried) 3 = Substantial impairment (significant impact, there were many things I couldn’t do) 4 = Extreme, incapacitating impairment (extensive impact, unable to socialize)

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36

SOR-Taste The following questions are about gustatory (taste) sensations that you may or not feel bothered by, such as textures and flavors of food or toothpaste/mouthwash. 1) How much have sensations like these bothered you (or made you uncomfortable)? 0 = Not at all bothered 1 = Mildly bothered (not too noticeable) 2 = Moderately bothered (noticeable, but still able to ignore it if I try) 3 = Severely bothered (very noticeable, difficult to focus on anything else) 4 = Extremely bothered (overwhelming, impossible to focus on anything else) 2) How often have you avoided certain places, situations, or activities because of not wanting to encounter taste sensations like these? Include ways you have modified activities or your behavior (e.g., avoided eating certain foods). 0 = Never 1 = Rarely (occasional avoidance. Little or no modification of my lifestyle) 2 = Sometimes (noticeable avoidance but still manageable. Only some modification of my lifestyle, no major changes) 3 = Often (extensive avoidance. Significant modification of my lifestyle - it was difficult to manage my usual activities or relied a lot on other people to do things for me) 4 = Always (overwhelming or constant avoidance. Extensive modification of my lifestyle - I was not able to do important activities I needed to do on my own) 3) How much has the discomfort caused by taste sensations like these interfered with your ability to work or perform your responsibilities at home? 0 = No interference 1 = Slight interference (little or no difficulty, could do most tasks I needed to do) 2 = Significant interference (some difficulty, I still managed to do most things if I tried) 3 = Substantial impairment (significant difficulty, there were many things I couldn’t do because of sensory discomfort) 4 = Extreme, incapacitating impairment (extensive difficulty, unable to manage important tasks because of sensory discomfort) 4) How much has the discomfort caused by taste sensations like these interfered with your social activities? 0 = No interference 1 = Slight interference (little or no impact on my social life) 2 = Significant interference (some impact, I still managed to do most things if I tried) 3 = Substantial impairment (significant impact, there were many things I couldn’t do) 4 = Extreme, incapacitating impairment (extensive impact, unable to socialize)

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37

Table 1. Demographic and clinical data for TTM and non-affected comparison samples TTM Sample (N = 609)

Non-Affected Comparison Sample N = 268)

Female

96%

56%

White

90%

81%

Hispanic

6%

9%

18 to 24 years

29%

10%

25 to 34 years

34%

43%

35 to 44 years

20%

27%

> 45 years

18%

19%

Currently living in US

73%

100%

College-educated

54%

52%

MGH-HPS

M = 16.65 (SD = 4.99)

M=0

SOR - Touch

4.47 (3.69), range 0-16

2.55 (2.83), range 0-12

SOR - Hearing

4.29 (3.84), range 0-16

2.74 (2.96), range 0-15

Age

38

MIST-Auto

29.23 (8.36)

----

52.79 (17.12)

----

17.08 (7.84)

----

FMPS - Total

90.54 (22.78)

----

FMPS - CM

27.96 (9.19)

----

FMPS - PS

23.86 (6.50)

----

FMPS - PE

14.84 (5.32)

----

FMPS - PC

11.26 (4.74)

----

FMPS - DA

12.62 (3.87)

----

FMPS - O

21.52 (5.60)

----

MIST-Focused

SDS

Note. MGH-HPS = Massachusetts General Hospital Hairpulling Scale, SOR = Sensory OverResponsivity, MIST = Milwaukee Inventory for Subtypes of Trichotillomania, SDS = Sheehan Disability Scale, FMPS = Frost Multidimensional Perfectionism Scale, CM = Concern over mistakes, PS = Personal standards, PE = Parental expectations, PC = Parental criticism, DA = Doubting of actions, O = Organization. In TTM sample, N’s range from 585 to 609 due to occasional missing data. Standard deviations appear in parentheses next to means.

39

Table 2 SOR-Touch

SOR-Hearing

SOR-Sight

SOR-Smell

SOR-Taste

SOR-Touch

---

---

---

---

---

SOR-Hearing

0.57***

---

---

---

---

SOR-Sight

0.45***

0.40***

---

---

---

SOR-Smell

0.57***

0.47***

0.38***

---

---

SOR-Taste

0.49***

0.40***

0.40***

0.41***

---

Note. *** p<.001

40

Table 3. Pearson’s correlations between SOR severity and clinical measures in TTM sample SOR Tactile

SOR Auditory

MGH-HPS

.193**

.076

MISTFocused

.230**

.184**

MISTAutomatic

.188**

.072

FMPS-Total

.272**

.256**

FMPS-CM

.287**

.245**

FMPS-PS

.125**

.137**

FMPS-PE

.084*

.078

FMPS-PC

.176**

.207**

FMPS-DA

.382**

.331**

FMPS-O

-.031

-.009

TTM-BP-C

.188**

.107

TTM-BP-L

.109*

.135*

Note. *p<.05, ** p<.01, *** p<.001

41

Highlights

    

Investigation of sensory-over responsivity (SOR) in trichotillomania (TTM) Participants with TTM had significantly higher levels of SOR than comparison sample Greater SOR correlated with perfectionism and by-proxy pulling urges SOR was positively correlated with impairment when controlling for TTM severity Findings suggest SOR may relate to maladaptive emotion regulation processes in TTM