Protocol for a randomised controlled pilot trial for transcranial direct current stimulation enhanced exposure and...

Case studies examining the benefits of transcranial direct current stimulation (tDCS) enhanced exposure response prevention (ERP) reveal clinically significant improvements in symptoms of obsessive-compulsive disorder (OCD). In the absence of control conditions, the validity of these findings requires further study. Efforts are also needed to enhance the longevity of any gains.

This paper presents the protocol for a pilot randomised controlled trial (RCT) that will, (1) examine the efficacy and longevity of a dual protocol approach combining tDCS and ERP for the treatment of OCD, and (2) pilot a personalised feedback-informed booster treatment protocol for the long-term maintenance of OCD gains. A double-blind between-subjects design is proposed to evaluate pre to post intervention gains in both conditions across an initial 10 session (4 weeks) treatment protocol and 6-month post intervention maintenance phase. tDCS will involve 20 minutes of 2 mA stimulation targeting the orbitofrontal cortex (cathode) and Pre-supplementary Motor Area (anode) as per the frontostriatal model of OCD. The primary outcome of this study is changes in OCD symptom severity (Yale-Brown Obsessive Compulsive Scale; YBOCS). Secondary outcomes include changes in depression, anxiety, quality of life, neurocognitive function (inhibitory control and cognitive flexibility), and treatment acceptability.

The findings of this study will inform treatment approaches by demonstrating the efficacy of tDCS enhanced ERP for the treatment of OCD, and whether any treatment gains can be maintained with feedback-informed booster treatment sessions.