SOSkin: a randomized clinical trial of on-line cognitive-behavioral therapy for Skin Picking Disorder.

Background: Cognitive Behavioral Therapy (CBT) is an effective treatment for Skin Picking Disorder (SPD). However, since individuals have limited access to CBT, telepsychotherapy can overcome this barrier.

Objective: Evaluate the efficacy of a self-guided digital CBT intervention for SPD.

Methods: This controlled clinical trial randomized 163 patients with SPD to receive 4 weeks of online CBT (SOSkin) or a control intervention (videos about quality of life). Primary outcome was the improvement in the Skin Picking Scale-Revised (SPS-R) and secondary outcomes were the improvement in Dermatology Life Quality Index Scale (DLQI), Generalized Anxiety Disorder Assessment Scale (GAD-7), and Patient Health Questionnaire-9 Scale (PHQ-9). Instruments were applied at baseline, middle and end of intervention and at 1 and 3 months of follow up. SOSkin usability was evaluated using the System Usability Scale (SUS). Data were analyzed using the Generalized Estimating Equations model (GEE).

Conclusion: There was no difference between groups in completion rates. SOSkin has excellent usability. Both groups improved the SPS-R and the DLQI scores after treatment and at the follow-up assessments. We found a significant time*group interaction in favor of CBT on SPS-R. Effect size of the intervention compared to control over SPS-R was small after treatment and at the follow-ups; over the DLQI was moderate after treatment and small at the follow-ups. CBT was superior to control on SPS-R when we compared the percentage of change from baseline. CBT was superior to control condition over DLQI at the end of treatment and at 1 month follow-up.