Habit as a therapeutic component in psychological treatment for obsessive-compulsive disorder: A randomised controlled feasibility study

Introduction: Cognitive-behavioural therapy (CBT) with exposure and response prevention (ERP) represents a first-line intervention for obsessive-compulsive disorder (OCD), but many patients either do not tolerate or respond to it. Habit-reversal therapy (HRT) is used to treat a variety of disorders characterised by repetitive behaviours. HRT involves learning a non-pathological motor habit to help extinguish repetitive behaviour. Augmenting ERP with components of HRT represents a novel candidate treatment approach for OCD. Aims: A randomised controlled trial (RCT) investigating the feasibility, acceptability, tolerability, and effectiveness of CBT + ERP augmented with a non-pathological habit in patients with OCD. Methods: Forty-five treatment-seeking individuals with OCD were randomly allocated to 12 weeks CBT + ERP augmented with a smartphone-induced habit, comprising a learnt finger sequence, applied during exposure (N = 22) or 12 weeks CBT + ERP (N = 23) as the control. Participants randomised to the experimental arm underwent 6–8 weeks habit-training first. Participants were assessed using blinded-raters for OCD severity (Yale-Brown Obsessive-Compulsive Scale; Y-BOCS) (primary outcome), depression (Montgomery-Åsberg Depression Rating Scale; MADRS), anxiety (State-Trait Anxiety Inventory-State; STAI-S), intolerance of uncertainty (Intolerance of Uncertainty Scale; IUS), and functional disability (Sheehan Disability Scale; SDS). We applied a conservative, intent-to-treat (ITT) analysis using the last observation carried forward (LOCF). Results: Twenty-eight (62%) participants (CBT + ERP + Habit = 11; CBT + ERP = 17) completed the trial. There was a significant reduction in Y-BOCS during habit-training (p < .05), prior to initiation of any psychological treatment. There were no significant between-arm differences on the Y-BOCS or any other clinical rating, nor in premature discontinuation rates at the endpoint. However, a larger number of participants dropped out during the habit training phase (7/22). Reported adverse events (measured during the treatment phase) were significantly fewer in the experimental arm (p < .001). Equivalent within-group improvement was seen in both arms on the Y-BOCS and IUS (all p < .05). Only those within the control arm experienced improvement in the MADRS (p < .01) and SDS (p < .05). Anxiety did not change in either arm. Conclusion: This small feasibility study limited by methodological confounds suggests habit-augmented CBT could be efficacious and well-tolerated in OCD. The improvements resulting from habit-training alone were unexpected and suggest novel treatment-approaches activating motor systems for OCD merit further investigation.