Hair Pulling Severity Research Articles

Neurocognitive functioning in adults with trichotillomania: Predictors of treatment response and symptom severity in a randomized control trial

Trichotillomania (TTM) is associated with impairments in response inhibition and cognitive flexibility, but it is unclear how such impairments relate to treatment outcome. The present study examined pre-treatment response inhibition and cognitive flexibility as predictors of treatment outcome, change in these domains from pre-to post-treatment, and associations with TTM severity. Participants were drawn from a randomized controlled trial comparing acceptance-enhanced behavior therapy (AEBT) to psychoeducation and supportive therapy (PST) for TTM. Adults completed assessments at pre-treatment (n = 88) and following 12 weeks of treatment (n = 68). Response inhibition and cognitive flexibility were assessed using the Stop Signal Task and Object Alternation Task, respectively. Participants completed the MGH-Hairpulling Scale. Independent evaluators administered the NIMH-Trichotillomania Severity Scale and Clinical Global Impressions-Improvement Scale. Higher pre-treatment TTM severity was associated with poorer pre-treatment cognitive flexibility, but not response inhibition. Better pre-treatment response inhibition performance predicted positive treatment response and lower post-treatment TTM symptom severity, irrespective of treatment assignment. Cognitive flexibility did not predict treatment response. After controlling for age, neither neurocognitive variable changed during treatment. Response inhibition and cognitive flexibility appear uniquely related to hair pulling severity and treatment response in adults with TTM. Implications for treatment delivery and development are discussed.

A Review of Behavioral and Pharmacological Treatments for Adult Trichotillomania

Trichotillomania (TTM) is a psychiatric disorder involving chronic, recurrent urges to pull out one’s own hair, arising frequently in childhood and early adolescence. This disorder predominantly affects women and has a high co-morbidity with many other psychiatric conditions. Currently, the etiology is unknown, which makes treating TTM extremely difficult. While the epidemiology and proposed causes will be discussed briefly, the primary purpose of this review is to provide a comprehensive, updated summary of the psychological and pharmacological management options for patients diagnosed with TTM, as new clinical trial data for previously studied and novel treatments have become available within the last decade. Of the behavioral interventions, cognitive behavioral therapy (CBT) and habit reversal training (HRT) have demonstrated the greatest improvements in hair-pulling severity, with HRT showing the most efficacy for long-term maintenance of progress. Pharmacological therapies with the most success include Olanzapine, Clomipramine, and N-Acetylcysteine, though larger replication studies are needed. Selective serotonin reuptake inhibitors (SSRIs) have yielded inconsistent results in clinical trials, yet they are frequently prescribed for TTM. Naltrexone, Dronabinol, and Inositol are emerging as potential treatments, but the results suggest that additional studies are needed. Future research directions include larger placebo-controlled pharmacological trials, exploring the efficacy of combined behavioral and pharmacological approaches compared to monotherapy, and delving into the potential genetic and neurochemical contributions that may underlie TTM.

Pilot trial of a technology assisted treatment for trichotillomania

The present study examined the usability, acceptability, feasibility, and preliminary efficacy of a prototype wrist-worn motion detection device and accompanying mobile app, developed by HabitAware®, as a system for delivering self-administered Habit Reversal Training (HRT). As an exploratory aim, the effect of the device and HRT app combination was compared to a reminder bracelet. The pilot trial included 15 adults with trichotillomania who interacted with the device and app system (n = 10) or reminder bracelet (n = 5) for 4 weeks. Participants in the device and app condition reported high usability, acceptability, and perceived efficacy of the system. The device and HRT app combination reduced hair pulling severity. Individuals in the reminder bracelet condition also showed a significant improvement in hair pulling. A future efficacy study with a larger sample size, longer timeframe, and improved gesture detection algorithm is warranted.

Hair-Pulling Does Not Necessarily Serve an Emotion Regulation Function in Adults With Trichotillomania.

Background: Trichotillomania (TTM) has been associated with childhood trauma and perceived stress. While it has been hypothesized that hair-pulling regulate negative emotions, the relationship between childhood trauma, perceived stress, emotion regulation, and hair-pulling has not been well-studied.Methods: Fifty-six adults with TTM and 31 healthy controls completed the Childhood Trauma Questionnaire (CTQ), Perceived Stress Scale (PSS), and Difficulties in Emotion Regulation Scale (DERS). Hair-pulling severity was measured with the Massachusetts General Hospital-Hair Pulling Scale. CTQ, PSS, and DERS total scores were compared across groups using ANCOVA and the correlation between hair-pulling severity and emotion dysregulation was determined. Regression analyses were used to estimate the association of CTQ and PSS totals with DERS, and to determine whether associations between predictors and dependent variable (DERS) differed across groups.Results: TTM patients reported higher rates of childhood trauma (p <= 0.01), perceived stress (p = 0.03), and emotion dysregulation (p <= 0.01). There was no association between emotion dysregulation and pulling severity (r = −0.02, p = 0.89). Perceived stress was associated with emotion dysregulation in both groups (p < 0.01), and no association between childhood trauma and emotion dysregulation in either group. Perceived stress was the only significant predictor of emotion dysregulation in both groups (F = 28.29, p < 0.01).Conclusion: The association between perceived stress and emotion dysregulation is not specific to TTM, and there is no association between emotion dysregulation and hair-pulling severity, suggesting that key factors other than emotion dysregulation contribute to hair-pulling. Alternative explanatory models are needed.

Working memory training in adults with trichotillomania: A 5-week, single-blind, randomized controlled study

ObjectiveThis randomized controlled study investigated the effect of the Cogmed Working Memory Training (CWMT) program on hair-pulling severity and working memory in trichotillomania (TTM). Methods36 adults with TTM were assigned to CWMT or active control (25 sessions, 5 weeks). Data from intention-to-treat [ITT] (CWMT: N = 21; control: N = 15) and per-protocol (CWMT: N = 16; control: N = 13) samples were analyzed. The primary and secondary outcomes were the totals on the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) and the Digit Span (Backward) subtest of the Wechsler Adult Intelligence Scale. Assessments occurred at baseline, at 5 weeks, and 3 months post-training. A mixed-model repeated measures ANOVA was done, with the interaction of group x time as primary effect of investigation. ResultsRegarding hair-pulling severity, the interaction effect of group x time was not significant (p = 0.27). Regarding working memory, there was a significant group × time interaction in favour of CWMT (p = 0.03), with improvement in working memory from baseline to 5 weeks (p < 0.001, LS mean difference −1.98). ConclusionsCWMT is not superior to active control in reducing hair-pulling. Working memory improved significantly over the short term with CWMT. The findings are a novel contribution to work on cognitive training effects on problematic repetitive behaviours.

The Influence of Hair Pulling Styles in the Treatment of Trichotillomania

This report investigated the improvement in Automatic and Focused styles of hair pulling among youth with trichotillomania (TTM). Youth with TTM (N = 40) participated in a clinical trial that compared habit reversal training (HRT) to treatment-as-usual (TAU). Participants completed a baseline assessment to characterize hair pulling severity, self-reported hair pulling styles, and co-occurring psychiatric conditions. Youth were randomly assigned to receive eight weekly sessions of HRT or eight weeks of TAU. Afterward, youth completed a post-treatment assessment of hair pulling severity and hair pulling styles. Youth in the TAU condition then received eight weekly sessions of HRT and completed another post-treatment assessment. Analyses revealed that the Focused pulling style largely improved with HRT (d = 0.73) compared to TAU (d = 0.11). However, there was limited improvement for the Automatic pulling style following either HRT (d = 0.10) or TAU (d = -0.31). This same pattern of effects was also found during open-label treatment with HRT. Although behavior therapies such as HRT are the principle treatment for youth with TTM, the Automatic pulling style exhibited limited improvement to this therapeutic approach. Therefore, therapeutic strategies that enhance awareness to pulling behaviors may produce more robust outcomes to behavior therapy for youth with TTM.

Family functioning in pediatric trichotillomania, obsessive compulsive disorder, and healthy comparison youth

Pediatric trichotillomania (TTM) is an understudied condition that can be highly impairing; little is known about family environmental features that shape its development and course. We examined family functioning among age and gender-matched groups of youth with primary TTM (n = 30; mean age = 12.87), obsessive compulsive disorder (OCD; n = 30; mean age = 12.70), and no psychiatric history (healthy controls; HC; n = 30; mean age = 12.46). An additional group of n = 25 TTM cases was employed to examine relationships between TTM severity and family functioning. All youth completed standardized diagnostic assessment, including the Family Environment Scale (FES) and Children's Report of Parenting Behavior Inventory (CRPBI). Family functioning was more impaired among both TTM and OCD cases relative to controls, as evidenced by higher levels of child-reported FES conflict and lower cohesion, expressiveness, and organization. Less consistent findings emerged on parent report, with cohesion, but not conflict, distinguishing the HC and clinical groups. In keeping with prior research, parents of TTM-affected youth also reported lower expressiveness and cohesion than parents in the OCD group. There was limited evidence for links between hair-pulling severity and family impairment and no links to parenting behavior. Findings are discussed in terms of implications for family focused treatment.

White matter volume alterations in hair-pulling disorder (trichotillomania).

Trichotillomania (TTM) is a disorder characterized by repetitive hair-pulling resulting in hair loss. Key processes affected in TTM comprise affective, cognitive, and motor functions. Emerging evidence suggests that brain matter aberrations in fronto-striatal and fronto-limbic brain networks and the cerebellum may characterize the pathophysiology of TTM. The aim of the present voxel-based morphometry (VBM) study was to evaluate whole brain grey and white matter volume alteration in TTM and its correlation with hair-pulling severity. High-resolution magnetic resonance imaging (3T) data were acquired from 29 TTM patients and 28 age-matched healthy controls (CTRLs). All TTM participants completed the Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS) to assess illness/pulling severity. Using whole-brain VBM, between-group differences in regional brain volumes were measured. Additionally, within the TTM group, the relationship between MGH-HPS scores, illness duration and brain volumes were examined. All data were corrected for multiple comparisons using family-wise error (FWE) correction at p < 0.05. Patients with TTM showed larger white matter volumes in the parahippocampal gyrus and cerebellum compared to CTRLs. Estimated white matter volumes showed no significant association with illness duration or MGH-HPS total scores. No significant between-group differences were found for grey matter volumes. Our observations suggest regional alterations in cortico-limbic and cerebellar white matter in patients with TTM, which may underlie deficits in cognitive and affective processing. Such volumetric white matter changes may precipitate impaired cortico-cerebellar communication leading to a reduced ability to control hair pulling behavior.

The Beliefs in Trichotillomania Scale (BiTS): Factor analyses and preliminary validation.

The role of cognitions and beliefs in trichotillomania (TTM; hair pulling disorder) has been the subject of only limited investigation. This study aimed to develop and validate the Beliefs in TTM Scale (BiTS). A pool of 50 items based upon themes identified in previous research was administered online to 841 participants with and without self-reported problematic, non-cosmetic hair pulling behaviours. Exploratory and confirmatory factor analyses conducted in randomly split-halves of the sample supported retention of 14 items comprising three factors: negative self-beliefs, low coping efficacy, and perfectionism. The BiTS demonstrated satisfactory psychometric properties and all three subscales significantly correlated with greater hair pulling severity. Negative self-beliefs predicted hair pulling severity over and above mood symptoms, suggesting the importance of addressing self-construals in psychological treatments for TTM. Validation in a clinician diagnosed sample is required. Research supports cognitive therapies for treating trichotillomania (hair pulling disorder), although studies investigating the nature and role of cognitions and beliefs in this disorder have been lacking. This study developed and validated a self-report measure of three styles of beliefs most relevant to trichotillomania: negative self-beliefs, low coping efficacy, and perfectionism. Negative self-beliefs predicted the severity of trichotillomania symptoms over and above depression and anxiety, suggesting such cognitions may not necessarily be due to comorbidities. Future research should validate the new measure in a clinician diagnosed sample, and therapies for trichotillomania may be enhanced by targeting shame specifically.

Telepsychotherapy for trichotillomania: A randomized controlled trial of ACT enhanced behavior therapy

Despite its prevalence, quality treatment for trichotillomania is often difficult to find. The use of telepsychology has been an effective method for disseminating treatment services for a variety of mental health conditions. However, no research has examined the use of telepsychology to treat trichotillomania. This randomized controlled trial used Acceptance and Commitment Therapy Enhanced Behavior Therapy delivered by way of telepsychology to treat trichotillomania in adults. The study compared an active treatment condition (n = 12) to a delayed treatment waitlist control condition (n = 10). Results showed significant reductions in hair pulling severity from pre- to post-treatment compared to the waitlist condition. The 22 participants all received treatment and were combined to examine overall treatment effects from pre-treatment to a 12-week follow-up. The effect of treatment on hair pulling severity remained significant at follow-up. Measures of psychological flexibility and perceived shame also saw significant improvement. Quality of life, however, did not improve over the course of treatment. The findings demonstrate that telepsychology is a viable option to disseminate treatment for trichotillomania.

Trauma and trichotillomania: A tenuous relationship

Some have argued that hair pulling in trichotillomania (TTM) is triggered by traumatic events, but reliable evidence linking trauma to TTM is limited. However, research has shown that hair pulling is associated with emotion regulation, suggesting a connection between negative affect and TTM. We investigated the associations between trauma, negative affect, and hair pulling in a cross-sectional sample of treatment seeking adults with TTM (N=85). In the current study, participants’ self-reported traumatic experiences were assessed during a structured clinical interview, and participants completed several measures of hair pulling severity, global TTM severity, depression, anxiety, experiential avoidance, and quality of life. Those who experienced trauma had more depressive symptoms, increased experiential avoidance, and greater global TTM severity. Although the presence of a trauma history was not related to the severity of hair pulling symptoms in the past week, depressive symptoms mediated the relationship between traumatic experiences and global TTM severity. These findings cast doubt on the notion that TTM is directly linked to trauma, but suggest that trauma leads to negative affect that individuals cope with through hair pulling. Implications for the conceptualization and treatment of TTM are discussed.

Trait anger, anger expression, and anger control in trichotillomania: Evidence for the emotion regulation model

Researchers have proposed emotion regulation (ER) as one model of trichotillomania (TTM). This model suggests that hair pulling may function as a maladaptive coping mechanism given difficulty managing negative emotions such as anger. This study compared hair pullers versus the normative population on trait anger, anger expression, and anger control and explored whether there is a relationship between anger variables and hair pulling severity. 158 adult females with TTM or chronic hair pulling completed self-report measures of anger and hair pulling severity. Hair pullers reported significantly higher rates of inwardly directed anger and more difficulty controlling their inward anger. Frequency of inward directed anger was a significant predictor of hair pulling severity even after controlling for psychiatric illness, providing support for the ER model of TTM. These findings underscore the potential importance of understanding and addressing ER in TTM.

Comorbidity and quality of life in adults with hair pulling disorder

Hair pulling disorder (HPD; trichotillomania) is thought to be associated with significant psychiatric comorbidity and functional impairment. However, few methodologically rigorous studies of HPD have been conducted, rendering such conclusions tenuous. The following study examined comorbidity and psychosocial functioning in a well-characterized sample of adults with HPD (N=85) who met DSM-IV criteria, had at least moderate hair pulling severity, and participated in a clinical trial. Results revealed that 38.8% of individuals with HPD had another current psychiatric diagnosis and 78.8% had another lifetime (present and/or past) psychiatric diagnosis. Specifically, HPD showed substantial overlap with depressive, anxiety, addictive, and other body-focused repetitive behavior disorders. The relationships between certain comorbidity patterns, hair pulling severity, current mood and anxiety symptoms, and quality of life were also examined. Results showed that current depressive symptoms were the only predictor of quality of life deficits. Implications of these findings for the conceptualization and treatment of HPD are discussed.

Photographic Assessment of Change in Trichotillomania: Psychometric Properties and Variables Influencing Interpretation

Although photographic assessment has been found to be reliable in assessing hair loss in Trichotillomania, the validity of this method is unclear, particularly for gauging progress in treatment. The current study evaluated the psychometric properties of photographic assessment of change in Trichotillomania. Photographs showing hair loss of adults with Trichotillomania were taken before and after participating in a clinical trial for the condition. Undergraduate college students (N = 211) rated treatment response according to the photos, and additional archival data on hair pulling severity and psychosocial health were retrieved from the clinical trial. Photographic assessment of change was found to possess fair reliability (ICC = 0.53), acceptable criterion validity (r = 0.51), good concurrent validity (r = 0.30–0.36), and excellent incremental validity (ΔR 2 = 8.67, p < 0.01). In addition, photographic measures were significantly correlated with change in quality of life (r = 0.42), and thus could be considered an index of the social validity of Trichotillomania treatment. Gender of the photo rater and pulling topography affected the criterion validity of photographic assessment (partial η 2 = 0.05–0.11). Recommendations for improving photographic assessment and future directions for hair pulling research are discussed.

Affective regulation in trichotillomania before and after self-help interventions

ObjectiveTrichotillomania (TTM) is characterized by recurrent hair-pulling behaviours that cause significant distress. Deficits in affective regulation have been reported in individuals with TTM. We aimed to investigate temporal stability of affective regulation in TTM individuals. MethodsEighty-one TTM individuals underwent an online intervention. Affective Regulation Scale (ARS), Massachusetts General Hospital Hair-Pulling Scale (MGH-HPS), and Beck Depression Inventory (BDI) scores were obtained at baseline, post-treatment (4 weeks), and follow-up (6 months). We examined the effect of phenotypes including hair-pulling severity and depressive symptoms on absolute and relative stability of affective regulation over time, using multiple linear and hierarchical regression analyses. ResultsThe ARS total-score from the present TTM sample was significantly lower than the score from non-hair pullers (p < 0.001). ARS total-scores inversely correlated with the MGH-HPS total-scores at baseline (p = 0.001) and post-treatment (p = 0.02), and with BDI total-scores at all time-points (p < 0.001). Although ARS total-scores significantly increased, all ARS sub-scores, except guilt sub-scores, did not change over time, indicating absolute stability. Baseline ARS total-, and sub-scores (except tension) were found to predict their ARS follow-up scores (all p < 0.01), confirming relative stability (i.e., the extent to which the inter-individual differences remained the same over time). The relative stability of ARS total-scores and all but two sub-scores (irritability and guilt) were independent from BDI baseline scores. ConclusionsIndividuals with TTM reported deficits in affective regulation that demonstrated mostly high relative stability and partly absolute stability. Therefore, targeting to improve affective regulation in individuals with TTM during therapy is warranted.

Trichotillomania and personality traits from the five-factor model.

To examine whether personality traits have predictive validity for trichotillomania (TTM) diagnosis, pulling severity and control, and hair pulling style. In study 1, logistic regression was used with TTM cases (n=54) and controls (n=25) to determine if NEO Five-Factor Inventory (NEO-FFI) personality domains predicted TTM case vs. control classification. In study 2, hierarchical multiple regression was used with TTM cases (n=164) to determine whether NEO-FFI personality domains predicted hair pulling severity and control as well as focused and automatic pulling styles. TTM case vs. control status was predicted by NEO-FFI neuroticism. Every 1-point increase in neuroticism scores resulted in a 10% greater chance of TTM diagnosis. Higher neuroticism, higher openness, and lower agreeableness were associated with greater pulling severity. Higher neuroticism was also associated with less control over hair pulling. Higher neuroticism and lower openness were associated with greater focused pulling. None of the personality domains predicted automatic hair pulling. Personality traits, especially neuroticism, can predict TTM diagnosis, hair pulling severity and control, and the focused style of pulling. None of the personality traits predicted automatic pulling. Longitudinal studies are needed to determine whether personality variables predispose to TTM onset, impact disorder course, and/or result from hair pulling behavior.

Examining DSM criteria for trichotillomania in a dimensional framework: implications for DSM-5 and diagnostic practice

BackgroundDiagnosis of trichotillomania (TTM) requires meeting several criteria that aim to embody the core pathology of the disorder. These criteria are traditionally interpreted monothetically, in that they are all equally necessary for diagnosis. Alternatively, a dimensional conceptualization of psychopathology allows for examination of the relatedness of each criterion to the TTM latent continuum. ObjectivesFirst, to examine the ability of recently removed criteria (B and C) to identify the latent dimensions of TTM psychopathology, such that they discriminate between individuals with low and high degrees of hair pulling severity. Second, to determine the impact of removing criteria B and C on the information content of remaining diagnostic criteria. Third, to determine the psychometric properties of remaining TTM diagnostic criteria that remain largely unchanged in DSM-5; that is, whether they measure distinct or overlapping levels of TTM psychopathology. Fourth, to determine whether information content derived from diagnostic criteria aid in the prediction of disease trajectory (i.e., can relapse propensity be predicted from criteria endorsement patterns). MethodStatistics derived from item response theory were used to examine diagnostic criteria endorsement in 91 adults with TTM who underwent psychotherapy. ResultsThe removal of two criteria in DSM-5 and psychometric validity of remaining criteria was supported. Additionally, individual trait parameters were used to predict treatment progress, uncovering predictive power where none previously existed. ConclusionsDiagnostic criteria for TTM should be examined in dimensional models, which allow for nuanced and sensitive measurement of core symptomology in treatment contexts.

Body focused repetitive behaviors among Salvadorian youth: Incidence and clinical correlates

Body-focused repetitive behaviors (BFRBs; e.g., hair pulling, skin picking, and nail biting) can cause significant physical and psychological distress. However, data examining BFRBs in non-clinical youth is limited. This study examined parent-reports of the incidence and clinical correlates of BFRBs in 315 Salvadorian children (4–17 years). Forty-six percent had at least one BFRB; nail biting was commonly reported (34.6%), followed by skin picking (24.8%), and hair pulling (10.5%). Of those endorsing BFRBs, 13.7% reported elevated distress and/or interference due to these behaviors, including approximately one-third of skin pickers and hair pullers (8.3% and 2.9% of the total sample) and one-fifth of nail biters (7.3% of the total sample). Skin pickers and hair pullers, but not nail biters, had higher levels of internalizing and externalizing behaviors, poorer adaptive functioning, and more difficulties with inattention, compared to those who reported no BFRBs. Skin picking symptom severity was positively correlated with externalizing and internalizing behaviors. Nail biting symptom severity was associated with increased internalizing symptoms, while severity of hair pulling was not significantly associated with behavioral and emotional functioning. These data suggest that BFRBs are commonplace and may be associated with behavioral and emotional functioning.

Treating trichotillomania: A meta-analysis of treatment effects and moderators for behavior therapy and serotonin reuptake inhibitors

Few randomized controlled trials (RCTs) exist examining the efficacy of behavior therapy (BT) or serotonin reuptake inhibitors (SRIs) for the treatment of trichotillomania (TTM), with no examination of treatment moderators. The present meta-analysis synthesized the treatment effect sizes (ES) of BT and SRI relative to comparison conditions, and examined moderators of treatment. A comprehensive literature search identified 11 RCTs that met inclusion criteria. Clinical characteristics (e.g., age, comorbidity, therapeutic contact hours), outcome measures, treatment subtypes (e.g., SRI subtype, BT subtype), and ES data were extracted. The standardized mean difference of change in hair pulling severity was the outcome measure. A random effects meta-analysis found a large pooled ES for BT (ES = 1.41, p < 0.001). BT trials with greater therapeutic contact hours exhibited larger ES (p = 0.009). Additionally, BT trials that used mood enhanced therapeutic techniques exhibited greater ES relative to trials including only traditional BT components (p = 0.004). For SRI trials, a random effects meta-analysis identified a moderate pooled ES (ES = 0.41, p = 0.02). Although clomipramine exhibited larger ES relative to selective serotonin reuptake inhibitors, the difference was not statistically significant. Publication bias was not identified for either treatment. BT yields large treatment effects for TTM, with further examination needed to disentangle confounded treatment moderators. SRI trials exhibited a moderate pooled ES, with no treatment moderators identified. Sensitivity analyses highlighted the need for further RCTs of SRIs, especially among youth with TTM.

N-Acetylcysteine in the Treatment of Pediatric Trichotillomania: A Randomized, Double-Blind, Placebo-Controlled Add-On Trial

ObjectiveTo examine the efficacy of N-acetylcysteine (NAC) for the treatment of pediatric trichotillomania (TTM) in a double-blind, placebo-controlled, add-on study. MethodA total of 39 children and adolescents aged 8 to 17 years with pediatric trichotillomania were randomly assigned to receive NAC or matching placebo for 12 weeks. Our primary outcome was change in severity of hairpulling as measured by the Massachusetts General Hospital–Hairpulling Scale (MGH-HPS). Secondary measures assessed hairpulling severity, automatic versus focused pulling, clinician-rated improvement, and comorbid anxiety and depression. Outcomes were examined using linear mixed models to test the treatment×time interaction in an intention-to-treat population. ResultsNo significant difference between N-acetylcysteine and placebo was found on any of the primary or secondary outcome measures. On several measures of hairpulling, subjects significantly improved with time regardless of treatment assignment. In the NAC group, 25% of subjects were judged as treatment responders, compared to 21% in the placebo group. ConclusionsWe observed no benefit of NAC for the treatment of children with trichotillomania. Our findings stand in contrast to a previous, similarly designed trial in adults with TTM, which demonstrated a very large, statistically significant benefit of NAC. Based on the differing results of NAC in pediatric and adult TTM populations, the assumption that pharmacological interventions demonstrated to be effective in adults with TTM will be as effective in children, may be inaccurate. This trial highlights the importance of referring children with TTM to appropriate behavioral therapy before initiating pharmacological interventions, as behavioral therapy has demonstrated efficacy in both children and adults with trichotillomania.