Mechanisms of Change in Mindfulness-Based Cognitive Therapy in Adults With ADHD.

Mindfulness-based cognitive therapy (MBCT) has been demonstrated to be effective in adults with ADHD. The aim of the current study was to examine its possible working mechanisms. In the context of an randomized controlled trial (RCT), MBCT + TAU (treatment as usual) ( = 43) versus TAU ( = 51), we used mediation analyses to examine whether reduction of clinician-rated ADHD symptoms and improvement of positive mental health at 6-month follow-up had been mediated by change in mindfulness skills, self-compassion, and executive functioning over the course of MBCT. Increase of self-compassion mediated improvement of positive mental health at 6-month follow-up. Improvement of mindfulness skills or self-compassion did not mediate the reduction in ADHD symptoms. Additional analyses suggest that self-reported inhibition did. The effect of MBCT on ADHD symptoms and positive mental health thus occurred via different mechanisms of change, that is, by improvements in inhibition and self-compassion, respectively.