Long-term effects of mindfulness-based cognitive therapy in patients with obsessive-compulsive disorder and residual symptoms after cognitive behavioral therapy: Twelve-month follow-up of a randomized controlled trial.

We examined the long-term efficacy of mindfulness-based cognitive therapy (MBCT) compared to a psychoeducation group as an active control condition in patients with obsessive-compulsive disorder (OCD) with residual symptoms of OCD after cognitive behavioral therapy. A total of 125 patients were included in a bicentric, interviewer-blind, randomized, and actively controlled trial and were assigned to either an MBCT group (n = 61) or a psychoeducation group (n = 64). Patients' demographic characteristics and the results from our previous assessments have already been reported (Külz et al., 2019). At the 12-month follow-up the completion rate was 80%. OCD symptoms were reduced from baseline to follow-up assessment with a large effect, but no difference was found between groups. Exploratory analyses showed that a composite score of time occupied by obsessive thoughts, distress associated with obsessive thoughts, and interference due to obsessive thoughts differed between groups in the per-protocol analysis, with a stronger reduction in the MBCT group. At the 12-month follow-up, the two groups showed a similar reduction of symptoms. However, preliminary evidence indicates that MBCT has a superior effect on some aspects of OCD. This should be replicated in future studies.