Acceptance-enhanced behaviour therapy for trichotillomania (AEBT-T) is effective in a group setting and change in psychological inflexibility may predict symptom reduction
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- Institutt for psykologi 
Trichotillomania (TTM) is a debilitating and often chronic mental disorder, with a prevalence of about 1% according to conservative estimates. Common treatment approaches include pharmacological and behavioural interventions, the most studied of which is Habit Reversal Training (HRT). However, previously studied treatments have tended to produce limited and short-lived effects. A novel approach utilizing HRT enhanced with Acceptance and Commitment Therapy (ACT) has recently been developed, and shown promising results. In the current study, using preliminary data from the Norwegian Trichotillomania Project, 58 patients meeting full DSM-IV criteria for TTM were offered ten three-hour sessions of AEBT-T in groups no larger than six participants. Post-treatment reductions in symptom severity were large as measured by self-report (Cohen’s dz = 1.62) and clinician rating (Cohen’s dz = 2.49). Based on these same measures, 29.3 and 39.7% of participants met criteria for a clinically significant change, and 36.2 and 20.7% were abstinent (for one week or more) from hair-pulling at post-treatment. Following treatment, significant reductions were also found for indices of depression (Cohen’s dz = 0.57), and anxiety Cohen’s dz = 1.00). In the regression analysis, change in self-reported psychological inflexibility, the Critical theoretical component in ACT, emerged as a significant predictor of clinician rated posttreatment symptom severity (F(2, 38) = 8.34, p < .001, R2 = .305), when including pre-treatment symptom severity in the model. Despite several limitations, such as the uncontrolled single group design, the current study shows AEBT-T delivered in a group setting to be an effective treatment, on par with or better than previously studied group-delivered, and even some individually delivered treatments.