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While exposure and response prevention (ERP) is the first-line treatment for obsessive-compulsive disorder (OCD), up to half of patients do not effectively respond. In an effort to better understand the mechanisms behind ERP, the inhibitory learning model emphasizes the roles of increasing perceived self-efficacy and distress tolerance. While self-efficacy and distress tolerance have separately been shown to predict OCD symptoms and treatment outcomes, no studies have assessed their joint effects in ERP. The current study examined distress tolerance as a mediator of the relationship between self-efficacy and ERP outcomes. Patients in an intensive ERP-based treatment program (N = 116) completed weekly self-report measures. Over the course of treatment, as OCD symptoms reduced, self-efficacy and distress tolerance both significantly increased. Importantly, increases in self-efficacy and distress tolerance mediated each other in explaining symptom reduction, suggesting a possible bi-directional effect. The temporal relationship between changes in self-efficacy and distress tolerance is worthy of further investigation. In addition, the current sample had limited racial diversity and might not be representative of patients receiving lower levels of care. Findings merit replication to be ascertained of their reliability. Findings suggest that during ERP, patients gain confidence in their abilities both to cope with general challenges and to withstand distress, potentially helping them engage with exposures and overcome initial fears. These findings provide support for the inhibitory learning model and highlight the mechanistic roles of self-efficacy and distress tolerance in ERP. Clinical implications to target both in treatment are discussed. • Exposure and response prevention (ERP) is the first-line treatment for OCD • We examined changes of self-efficacy and distress tolerance over the course of ERP • Patients in an intensive treatment program completed weekly assessment measures • As OCD symptoms improved with ERP, self-efficacy and distress tolerance increased • Self-efficacy and distress tolerance mediated each other in reducing OCD symptoms and both should be important targets in ERP [ABSTRACT FROM AUTHOR]

Background: Behavioral treatments of body-focused repetitive behaviors are effective, but access to expert therapists is limited. Access might be improved by use of web-based self-help, but nonadherence limits the efficacy of these programs. This trial tested an intervention derived from the "strength" model of self-control (Baumeister et al in Perspect Psychol Sci 13:141–145, 2018) as a way to improve adherence to StopPulling.com (for trichotillomania; TTM) and StopPicking.com (for Skin Picking Disorder; SPD). Methods: Adult participants (N = 80; 40 with TTM and 40 with SPD) were randomly assigned to (a) 2-week self-control task (avoiding eating sweet foods) or (b) waitlist, followed by access to web-based self-help for 10 weeks and then post-test. Adherence was indexed by the number of days (0–70) on which the participant logged on and entered data in the self-help program. Results: There was no significant difference in adherence between the self-control condition (20% trimmed mean = 11.25) and the waitlist condition (9.37). Secondary analyses (a) replicated earlier work showing that participants who adhered more consistently derived more benefit and (b) suggested that symptom reduction trends were evident in the self-control condition even before the start of web-based self-help. Conclusions: Improving adherence is necessary for maximizing the benefit of web-based self-help. Self-control training does not appear to increase adherence but may have utility on its own for reducing BFRB symptoms. [ABSTRACT FROM AUTHOR]

Cognitive models implicate interpretation bias in the development and maintenance of obsessive compulsive and related disorders (OCRDs), and research supports Cognitive Bias Modification for Interpretation (CBM-I) in targeting this mechanism. However, prior studies in OCRDs have been limited to nonclinical populations, adolescents, and adults in a laboratory setting. This study evaluated the feasibility and acceptability of CBM-I as an adjunctive intervention during intensive/residential treatment (IRT) for adults with OCRDs. We modified a lab-based CBM-I training for adults seeking IRT for OCRDs, and conducted a feasibility trial (N = 4) and subsequent pilot RCT; participants (N = 31) were randomized to receive CBM-I or psychoeducation. Benchmarks were met for feasibility, acceptability, and target engagement. From pre- to post-intervention, the CBM-I group showed a large effect for change in interpretation bias (d = .90), whereas this effect was trivial (d = .06) for psychoeducation. This was the first study to evaluate CBM-I in naturalistic treatment for adults seeking IRT for OCRDs. Findings support the feasibility and acceptability of CBM-I in this novel sample and setting. A larger scale RCT is needed to determine whether CBM-I can enhance OCRD treatment response. [ABSTRACT FROM AUTHOR]

• Suicidal thoughts and behaviors remain understudied in OCD. • Examined implicit and explicit suicidality in adults receiving treatment for OCD. • 77 % reported lifetime suicidal thoughts; 16 % reported prior suicide attempt. • OCD severity was higher for those with lifetime suicidal thoughts and prior attempts. • Implicit biases towards death did not predict explicitly endorsed suicidality. Obsessive-compulsive and related disorders (OCRDs) are associated with increased risk of suicidal thoughts and behaviors (STBs), yet research characterizing suicidality in OCRDs remains limited. A major challenge in assessing STBs is the reliance on explicit self-report. This study utilized multi-method assessment to examine changes in both implicit and explicit STBs in 31 adults receiving partial/residential treatment for OCRDs. Assessments were administered at admission and weekly during treatment. Approximately three-quarters of participants reported lifetime suicidal thoughts, with 16 % reporting a prior suicide attempt. OCD severity was significantly correlated with lifetime suicidal thoughts, and was significantly higher for those with lifetime suicidal thoughts and prior attempts compared to those without. Implicit biases towards death were not associated with OCD severity, and did not predict explicitly endorsed STBs. This is the first study to measure both explicit and implicit STBs in adults with OCRDs. Limitations included small sample size and lack of racial/ethnic diversity. Given the majority had recent suicidal thoughts and one in six had a prior attempt, we emphasize the importance of STB assessment in OCD treatment settings. [ABSTRACT FROM AUTHOR]

Background: This study examined the temporal relations between obsessive beliefs, obsessions, and compulsions during treatment. Gaining a better understanding of these relations may inform targets for improving treatment response. We hypothesized that our results would support the goal-directed model of OCD whereby obsessive beliefs at time t, predict obsessions at time t + 1, which then predict compulsions at time t + 2. Methods: Participants were adults receiving intensive/residential treatment (IRT) for OCD (N = 446). Time points examined were admission, weeks 2 and 4, and discharge, utilizing a random intercepts cross-lagged panel model. Results: Results supported the reciprocal model of OCD, wherein both the goal-directed and habit-driven models coexist. Most of the significant paths between OCD symptoms were found early in treatment between weeks 2 and 4. Conclusions: These findings offer unique information regarding the temporal precedence of these relations, and they are consistent with prior cognitive models of OCD. The importance of targeting both obsessive beliefs and compulsions is highlighted by these findings. Future research would benefit from investigating moderators of OCD models. [ABSTRACT FROM AUTHOR]

Background: This study investigated distinct trajectories of treatment response in a naturalistic intensive/residential treatment (IRT) program for adults with severe obsessive-compulsive disorder (OCD). We hypothesized that: (1) distinct trajectories would emerge and (2) demographic variables, psychiatric comorbidity, OCD symptom subtype, level of insight, previous exposure and response prevention (ERP) treatment, and quality of life, would differentially predict assignment to these trajectories.Methods: Participants included 305 individuals with primary OCD admitted for IRT.Results: Two trajectories emerged over the course of the first eight weeks of treatment, with the vast majority of participants demonstrating treatment response. The first trajectory (96%, n = 292) showed a negative, linear treatment response (a.k.a. "linear responders") and more severe OCD symptoms at admission. The second trajectory (4%, n = 13) had less severe OCD symptoms at admission and did not exhibit a significant overall change in symptoms over the course of treatment. More specifically, this second trajectory or "u-shaped responders" show a non-significant linear response through week four of treatment, followed by slightly increased symptoms in week five. Assignment to these classes was not differentially predicted by hypothesized predictor variables.Limitations: Our final model had inconsistent fit indices and small class prevalance of the u-shaped responder group; therefore, model selection was based on both fit indices and substantive meaning.Conclusions: This study emprically derived two distinct trajectories of OCD symptom severity over the course of IRT. These findings have the potential to refine IRT for patients with severe OCD, and to potentially guide future investigation into the optimal delivery of ERP treatment for OCD generally. [ABSTRACT FROM AUTHOR]

• At baseline, females reported receiving greater FA than did males. • Treatment-related change in OC severity preceded change in FA by 1 month after IRT. • Change in FA preceded change in OC severity in the 6 months following IRT. Many adults with OCD experience residual symptoms following CBT, with or without medication. A potential target for enhancing treatment effectiveness is family accommodation (FA). This study examined (1) possible sociodemographic and clinical correlates of FA in adults presenting for intensive/residential treatment, and (2) temporal relationships between FA and OCD symptom severity during acute treatment and follow-up phases. Adult patients (N = 315) completed baseline measures of FA and OCD symptom severity at admission to IRT. Follow-up data were collected from a subset of participants (n = 111) at discharge, 1-month, and 6-month follow-up. Cross-lagged panel analysis showed that changes in OCD symptom severity from admission to discharge predicted changes in FA from discharge to 1-month follow-up. Increases in FA from discharge to 1-month follow-up predicted increases in OCD symptom severity from 1-month to 6-month follow-up. Female patients reported greater baseline FA from their family members than did males, and there were no significant differences in FA by relationship type or marital status. Contamination, Responsibility for Harm, and Symmetry/Incompleteness symptoms were each found to uniquely predict FA at admission. Results from this study provide support for the temporal precedence of FA reduction in OCD symptom improvement as adults transition home following residential treatment. [ABSTRACT FROM AUTHOR]

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 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 = .45) an d tactile ( t (655.24) = −8.38, p < .001, d = .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. [ABSTRACT FROM AUTHOR]

Predictors of successful PTSD outcome have been examined through individually delivered treatments. We examined predictors using a group protocol with cognitive, exposure, and skills modules. Assessments included self-report and interview (CAPS, SCID-I/II) measures at baseline, post, and six months; treatment was a 16-week, three-member group for 32 OEF/OIF women Veterans. A regression analysis showed major depressive disorder and no baseline psychiatric medication predicted PTSD improvement. PTSD improvement predicted fewer outpatient medical visits at follow-up. The results supported past research and challenged other findings (e.g., sexual assault predicts less improvement). An additional unique contribution was examining predictors in a group treatment format. [ABSTRACT FROM PUBLISHER]

This study aimed to concretize and pilot test comprehensive behavioral (ComB) treatment of trichotillomania (TTM), to facilitate rigorous testing of its efficacy. ComB provides a conceptualization to develop individualized treatment and choose interventions for managing distinct factors that maintain the individual’s hair pulling. It has been used by clinicians for almost three decades, yet was not previously manualized or studied empirically. A manual was drafted and revised based on patient (N = 16) and therapist feedback, an intervention choice study demonstrated therapists reliably selected model-consistent interventions, and a therapist adherence measure was developed and tested. Uncontrolled preliminary data showed ComB to be highly acceptable, and it led to reduced TTM symptom severity and impairment, with large effects. Quality of life and disability also improved, with effects maintained at follow-up. This study resulted in the development of a manual and measures to be used in a randomized controlled trial (RCT) of ComB for TTM. [ABSTRACT FROM AUTHOR]

Objective Treatment outcome was compared among non-Hispanic White and racial/ethnic minority participants with trichotillomania (TTM), or hair-pulling disorder. Method Symptom severity, quality of life, and TTM-related disability were compared in a behavior therapy trial with a stepped care approach: web-based self-help and then individual behavior therapy. The sample comprised 72% ( n = 38) non-Hispanic White participants and 28% ( n = 15) minority participants. Results The ethnic groups responded differently to treatment, with fewer minority participants showing improvement during web-based self-help. Response rates were equivalent between ethnic groups during the in-person behavior therapy. These results should be interpreted with caution because of the small sample size of minorities in the study and consequent inability to analyze results for each racial/ethnic group individually. Conclusions Future studies should focus on the investigation of factors that may enable or hinder racial and ethnic minority participants to benefit from online and/or self-help behavior therapy for TTM. [ABSTRACT FROM AUTHOR]

Exposure and response prevention (ERP) is an evidence-based treatment for obsessive-compulsive disorder (OCD). Theories for how it works vary in their emphasis on active mechanisms of change. The current study aimed to clarify mechanisms of change in ERP for OCD using network analysis, comparing ERP networks at the start and end of intensive treatment (partial hospital and residential). In our sample of 182 patients, the most central node in both networks was engagement with exposure, which was consistently related to greater understanding of ERP rationale, higher willingness, and less ritualization, accounting for all other variables in the network. There were no significant differences in networks between the start and end of treatment. These results suggest that nonspecific parameters like facilitating engagement in exposures without ritualizing and providing a clear rationale to clients may be key to effective treatment. As such, it may be useful for clinicians to spend adequate time underscoring the need to eliminate rituals to fully engage in exposure tasks and explaining the rationale for ERP prior to doing exposures, regardless of theoretical orientation. Nonetheless, findings represent group-level statistics and more fine-grained idiographic analyses may reveal individual-level differences with respect to central mechanisms of change. Other limitations include demographic homogeneity of our sample. • Examined mechanisms of change in exposures for OCD using network analysis • Engagement with exposure was consistently the most central node • Engagement was related to understanding rationale, willingness, and ritualizing • Clarifying rationale and practicing willingness may be important for engagement [ABSTRACT FROM AUTHOR]

Background: Transdiagnostic definitions of obsessive–compulsive and related disorders (OCRDs) may represent useful treatment targets. The current study sought to characterize higher order dimensions underpinning the OCRDs in the Diagnostic and Statistical Manual of Mental Disorders—Fifth Edition, and examine their course during treatment. Methods: Adult patients (N = 407) completed measures of OCRDs, depression, and worry before and after intensive/residential treatment for OCRDs. Structural equation modeling was used to examine the comorbidity structure and temporal course of the symptoms. Results: Covariation of the symptoms was best represented by three dimensions: distress (depression and worry), compulsivity (obsessive–compulsive disorder, hoarding, and body dysmorphia), and grooming (hair pulling and skin picking). Latent change score modeling revealed significant reduction in the means of all three dimensions across treatment (Cohen's ds = −1.04, −0.62, and −0.23 for distress, compulsivity, and grooming, respectively). There was a strong correlation between change in compulsivity and grooming (r =.67) and change in compulsivity and distress (r =.80), but a small correlation between change in grooming and distress (r =.35). Conclusions: The results indicate that OCRDs are underpinned by higher order compulsivity and grooming dimensions that differ in their association with distress. The results further suggest that the two dimensions may reflect promising intervention targets suitable for transdiagnostic treatment protocols. [ABSTRACT FROM AUTHOR]

Objective: There are effective treatments of trichotillomania (TTM), but access to expert providers is limited. This study tested a stepped care model aimed at improving access. Method: Participants were 60 (95% women. 75% Caucasian. 2% Hispanic) adults (M = 33.18 years) with TTM. They were randomly assigned to immediate versus waitlist (WL) conditions for Step I (10 weeks of web-based self-help via StopPulling.com). After Step 1. participants chose whether to engage in Step 2 (8 sessions of in-person habit reversal training [HRT]). Results: In Step 1. the immediate condition had a small (d = .21) but significant advantage, relative to WL. in reducing TTM symptom ratings by interviewers (masked to experimental condition but not to assessment point); there were no differences in self-reported TTM symptoms, alopecia, functional impairment, or quality of life. Step 1 was more effective for those who used the site more often. Stepped care was highly acceptable: Motivation did not decrease during Step 1; treatment satisfaction was high, and 76% enrolled in Step 2. More symptomatic patients self-selected into HRT. and on average they improved significantly. Over one third (36%) made clinically significant improvement in self-reported TTM symptoms. Considering the entire stepped care program, participants significantly reduced symptoms, alopecia, and impairment, and increased quality of life. For quality of life and symptom severity, there was some relapse by 3-month follow-up. Conclusions: Stepped care is acceptable, and HRT was associated with improvement. Further work is needed to determine which patients with TTM can benefit from self-help and how to reduce relapse. [ABSTRACT FROM AUTHOR]

Background: Maintenance of gains with cognitive-behavioral treatment for trichotillomania (TTM) has historically been problematic. Methods: We conducted follow-up assessments 3 and 6 months after completion of a 3-month maintenance phase on 10 individuals with DSM-IV-TR TTM who participated in an open trial of a dialectical behavior therapy (DBT)-enhanced habit reversal treatment (HRT). Results: Significant improvement from baseline was reported at 3-and 6-month follow-up on all measures of hair pulling severity and emotion regulation, although some worsening was reported on some measures from earlier study time points. At 6-month follow-up, five and four participants were full and partial responders, respectively. Significant correlations were reported at both follow-up time points between changes in hair pulling severity and emotion regulation capacity. Conclusions: DBT-enhanced HRT offers promise for improved long-term treatment results in TTM. Changes in TTM severity from baseline to 3-and 6-month follow-up is correlated with changes in emotion regulation capacity. Depression and Anxiety, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

As research and clinical settings increasingly emphasize questions of change, it is crucial that our mechanistic and outcome variables are established as reliable and valid measures of such change. However, there is often a mismatch between the purposes for which symptom measures were developed and validated versus their application. Traditional psychometric theory has focused largely on between-person change, whereas increasingly research and clinical questions concern within-person change. We examined the psychometric properties of two commonly used measures of obsessive–compulsive symptoms (Yale–Brown Obsessive Compulsive Scale, YBOCS; Dimensional Obsessive–Compulsive Scale, DOCS) within a longitudinal treatment context (N = 570). Regarding reliability, we applied traditional (i.e., internal consistency at each week) and novel methods that allow for examination of the reliability of both within- and between-person change (i.e., variance partitioning based on generalizability theory). We examined longitudinal concurrent validity by correlating per-person slopes of obsessive–compulsive and depression symptom measures obtained via mixed-effects models. Within-person change reliability was acceptable or good for the YBOCS and DOCS total scores (.77,.83), suggesting that these measures are capable of capturing meaningful changes that exist within persons over time, and between-person change reliability was excellent (.99–1.0). Per-person slopes analyses supported the longitudinal concurrent validity of both measures. Our data support the continued use of the YBOCS and DOCS as measures of obsessive–compulsive symptoms for the purpose of many longitudinal research questions. The current study provides a template for reestablishing the psychometric properties of other commonly used measures in the context of longitudinal investigations. Public Significance Statement: Within research and clinical settings, it is crucial that the measures used to assess change are established as reliable and valid (i.e., consistently measuring changes in the constructs expected to change during treatment). Our research using novel statistical methods suggests that two measures of obsessive–compulsive symptoms (YBOCS and DOCS) meaningfully capture changes that occur within individuals during treatment, as well as differences between individuals. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to characterise international trends in the use of psychotropic medication, psychological therapies, and novel therapies used to treat obsessive–compulsive disorder (OCD). Methods: Researchers in the field of OCD were invited to contribute summary statistics on the characteristics of their samples. Consistency of summary statistics across countries was evaluated. Results: The study surveyed 19 expert centres from 15 countries (Argentina, Australia, Brazil, China, Germany, Greece, India, Italy, Japan, Mexico, Portugal, South Africa, Spain, the United Kingdom, and the United States) providing a total sample of 7,340 participants. Fluoxetine (n = 972; 13.2%) and fluvoxamine (n = 913; 12.4%) were the most commonly used selective serotonin reuptake inhibitor medications. Risperidone (n = 428; 7.3%) and aripiprazole (n = 415; 7.1%) were the most commonly used antipsychotic agents. Neurostimulation techniques such as transcranial magnetic stimulation, deep brain stimulation, gamma knife surgery, and psychosurgery were used in less than 1% of the sample. There was significant variation in the use and accessibility of exposure and response prevention for OCD. Conclusions: The variation between countries in treatments used for OCD needs further evaluation. Exposure and response prevention is not used as frequently as guidelines suggest and appears difficult to access in most countries. Updated treatment guidelines are recommended. [ABSTRACT FROM AUTHOR]

Objectives: To assess the rates of co-occurring putative 'behavioural addictions' in patients with obsessive-compulsive disorder (OCD). Methods: Twenty-three international centres specialising in the treatment of OCD were invited to participate in a survey of the rates of behavioural addictions and other relevant comorbidity within their samples. Results: Sixteen of 23 (69.6%) invited centres from 13 countries had sufficient data to participate in the survey. The use of validated diagnostic tools was discrepant, with most centres relying on a 'clinical diagnosis' to diagnose behavioural addictions. The final sample comprised of 6916 patients with a primary diagnosis of OCD. The reported rates of behavioural addictions were as follows: 8.7% for problematic internet use, 6.8% for compulsive sexual behaviour disorder, 6.4% for compulsive buying, 4.1% for gambling disorder and 3.4% for internet gaming disorder. Conclusions: Behavioural addictions should be better assessed for patients with OCD. The absence of diagnostic scales developed specifically for behavioural addictions and overlapping obsessive-compulsive phenomena such as compulsive checking of information on the internet may explain the relatively high rate of problematic internet use in this sample. The study encourages better efforts to assess and to conceptualise the relatedness of behavioural addictions to obsessive-compulsive 'spectrum' disorders. [ABSTRACT FROM AUTHOR]

Abstract: Objective: This study aimed to develop and validate the Distress Tolerance Scale‐Short Form (DTS‐SF), a modification of the original Distress Tolerance Scale, in a severe/complex sample of individuals with obsessive compulsive disorder (OCD). Currently, there are multiple self‐report measurements of distress tolerance (DT), highlighting the need for a more refined measure. Method: Participants included 222 individuals with a primary diagnosis of OCD (57% male, average age = 31) seeking intensive/residential treatment. Participants completed surveys at admission, discharge, and each week. Results: An exploratory factor analysis revealed a one‐factor solution representing overall DT ability. The DTS‐SF was found to be sensitive to treatment effects. Appropriate associations between the DTS‐SF and other measures were also found, with lower DT associated with greater OCD and depression severity and lower reported quality of life. Conclusion: The DTS‐SF was found to be a valid and reliable measure with high clinical utility for quickly and accurately measuring DT. [ABSTRACT FROM AUTHOR]

Exposure and response prevention is the gold-standard treatment for obsessive compulsive disorder (OCD), yet up to half of patients do not adequately respond. Thus, different approaches to identifying and intervening with non-responders are badly needed. One approach would be to better understand the functional connections among aspects of OCD symptoms and, ultimately, how to target those associations in treatment. In a large sample of patients who completed intensive treatment for OCD and related disorders (N = 1343), we examined whether differences in network structure of OCD symptom aspects existed at baseline between treatment responders versus non-responders. A network comparison test indicated a significant difference between OCD network structure for responders versus non-responders (M = 0.19, p =.02). Consistent differences emerged between responders and non-responders in how they responded to emotional distress. This pattern of associations suggests that non-responders may have been more reactive to their distress by performing compulsions, thereby worsening their functioning. By examining the association between baseline distress intolerance with other symptom aspects that presumably maintain the disorder (e.g., ritualizing), clinicians can more effectively target those associations in treatment. • Baseline network analysis of OCD treatment responders versus non-responders. • Responders and non-responders differed in symptom network structure at baseline. • Differences emerged between groups in the ways they oriented towards their distress. • Non-responders were more reactive to their distress by performing compulsions. • Among non-responders, distress was more tightly linked to functional interference. [ABSTRACT FROM AUTHOR]

Different studies of the treatment of trichotillomania (TTM) have used varying standards to determine the proportion of patients who obtain clinically meaningful benefits, but there is little information on the similarity of results yielded by these methods or on their comparative validity. Data from a stepped-care (Step 1: Web-based self-help; Step 2: Individual behavior therapy; N = 60) treatment study of TTM were used to evaluate 7 potential standards: complete abstinence, ⩾25% symptom reduction, recovery of normal functioning, and clinical significance (recovery + statistically reliable change), each of the last 3 being measured by self-report (Massachusetts General Hospital Hairpulling Scale; MGH-HPS) or interview (Psychiatric Institute Trichotillomania Scale). Depending on the metric, response rates ranged from 25 to 68%. All standards were significantly associated with one another, though less strongly for the 25% symptom reduction metrics. Concurrent (with deciding to enter Step 2 treatment) and predictive (with 3-month follow-up treatment satisfaction, TTM-related impairment, quality of life, and diagnosis) validity results were variable but generally strongest for clinical significance as measured via self-report. Routine reporting of the proportion of patients who make clinically significant improvement on the MGH-HPS, supplemented by data on complete abstinence, would bolster the interpretability of TTM treatment outcome findings. [ABSTRACT FROM AUTHOR]