 The purpose of this study is to assess and compare the overall efficacy and differential effects of two interventions for patients suffering from obsessive-compulsive disorder OCD according to DSM-5. The interventions to be compared are detached mindfulness DM and cognitive restructuring CR. Whereas the efficacy of CR for the treatment of OCD has been proven in various studies, the efficacy of DM as a single intervention so far has only been shown within a case study and within a non-clinical sample. By contrast, the efficacy of complex metacognitive protocols of which DM constitutes one of several single interventions has been shown multiple times. So far, however, little is known about the efficacy of DM as a single intervention in a clinical sample and the differential working mechanisms of DM vs. CR. 