Does cognitive bias modification prior to standard brief cognitive behavior therapy reduce relapse rates in hair pulling disorder? A double-blind randomized controlled trial

Background: In line with previous research in alcohol addiction, we tested whether an Approach-Avoidance Training (AAT) prior to standard six-session Cognitive Behavior Therapy (CBT) for Hair Pulling Disorder (HPD) reduced problematic relapse, commonly found in this population. Method: Prior to CBT, 54 outpatients with a primary diagnosis of HPD were randomly assigned (double-blind) to either a training condition (n = 27), learning to avoid hair-pulling-related stimuli, or to a control condition (n = 27). Symptom severity was assessed with the Massachussetts General Hospital Hairpulling Scale, Severity Urge Resistance Frequency Scale, Self-Control Cognition Questionnaire, and Alopecia Scale. Results: In line with existing research, CBT showed to be an effective treatment for HPD in the short-term. There was no significant symptom increase after one and three months, but effect sizes were reduced approximately by half at the twelve-month measurement. The AAT training prior to CBT did not result in enhanced symptom reduction or reduced relapse after CBT. Conclusions: AAT training could not resolve the substantial relapse after successful CBT. Future research should take into account the complexity of stimuli that elicit hair pulling (e.g., tactile stimuli) and consider investigating other types of biases.