Dermatillomania is characterised by repetitive skin picking, resulting in tissue damage and significant distress and/or functional impairment. Cognitive behavioural therapy (CBT) is the recommended psychological intervention for dermatillomania in clinical guidelines, with the evidence base also supporting habit reversal training (HRT) as part of CBT. However, research evaluating CBT and HRT for dermatillomania remains scarce. This case study describes a young woman with dermatillomania, in the context of co-morbid anxiety and low mood, treated with 20 sessions of CBT including HRT in a community setting. Guided by her formulation, additional techniques such as those fostering self-compassion were also integrated, and sociocultural factors were adapted for. Improvements were reported in client-centred goals and outcomes of global psychological distress, functioning, anxiety and symptoms and psychosocial impacts of skin picking. The intervention was well received by the client. Limitations as well as clinical practice implications and research recommendations for dermatillomania are discussed.

1. (1) To understand using CBT, including HRT, to treat a case of dermatillomania in the context of anxiety and depression.

2. (2) To use a formulation-driven approach to guide the intervention.

3. (3) To consider adapting interventions for sociocultural factors.

Chronic tic disorders may have a major impact on a child's function. A significant effect has been shown for combined habit reversal training (HRT) and exposure response prevention (ERP) treatment delivered in an individual and group setting.

The present study examines predictors and moderators of treatment outcome after an acute therapeutic intervention.

Fifty-nine children and adolescents were randomised to manualised treatment combining HRT and ERP as individual or group training. Age, gender, baseline tic severity, Premonitory Urge for Tics Scale (PUTS) scores, Beliefs about Tic Scale (BATS) scores, hypersensitivity and comorbid psychiatric symptoms were analysed as predictors of outcome. The same characteristics were examined as moderators for individual versus group treatment. Outcome measures included the change in total tic severity (TTS) score and functional impairment score (as measured by the Yale Global Tic Severity Scale (YGTSS)).

Internalising symptoms predicted a lesser decrease in functional impairment. The occurrence of obsessive–compulsive symptoms predicted a larger decrease in TTS. Baseline hypersensitivity and high scores on depressive symptoms favoured individual treatment. High baseline PUTS scores favoured group therapy.

This is the first study examining factors predicting and moderating perceived functional impairment following a therapeutic intervention. The study adds to the knowledge on predictors and moderators of TTS. Furthermore, this is the first study examining the effect of the BATS score. The study points towards factors that may influence treatment outcome and that require consideration when choosing supplemental treatment. This applies to comorbid anxiety and depressive symptoms, and to the child's belief about their tics and premonitory urge.

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