Improving outcomes of Cognitive Behavioural Therapy for Obsessive-Compulsive Disorder: exploring engagement and the potential of mindfulness-based interventions

Research evidence shows that although Cognitive Behavioural Therapy (CBT) is a highly effective therapy and the gold standard in the treatment of Obsessive-Compulsive Disorder (OCD), a significant proportion of adults with OCD do not experience a clinically meaningful reduction in OCD symptoms post-treatment. As CBT for OCD is a challenging therapy, this may, at least in part, reflect poor patient engagement. The modest response rate also invites exploration of other psychological therapies that may enhance treatment outcomes. The first aim of the thesis was to examine patient engagement in CBT for OCD. This was achieved through a systematic review and meta-analysis of the magnitude, predictors and reasons for patient non-adherence, specifically refusal, dropout, session attendance and CBT task engagement, to CBT for OCD (paper 1), followed by a qualitative exploration, employing thematic analysis, of patients’ perceptions of the barriers and facilitators to engagement in group CBT for OCD (paper 2). The second aim was to explore whether mindfulness-based interventions (MBIs) show potential for adults with OCD. Towards this aim, the thesis first examined the relationship of obsessive-compulsive symptoms with mindfulness and self-compassion in a large sample of treatment-seeking adults and tested whether mindfulness and self-compassion contributed to explaining obsessive-compulsive symptoms over and above depression severity, obsessive beliefs and distress tolerance (paper 3). This was followed by a qualitative analysis of patient experiences of MBIs, specifically mindfulness-based ERP (MB-ERP) and Mindfulness-based Cognitive Therapy adapted for OCD (MBCT-OCD) to elucidate whether these MBIs were perceived as acceptable and potentially efficacious treatments for OCD and to explore how they might achieve their positive effects (paper 4). After a general introduction, the four papers are presented, followed by a general discussion of results, a reflection on the strengths and limitations of the thesis and its clinical and research implications.