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.