Mechanisms of change in cognitive therapy for obsessive compulsive disorder: Role of maladaptive beliefs and schemas

•We sought to identify mediators of improvement in cognitive therapy (CT) for OCD.•Participants included 36 adults with OCD who received CT over 24 weeks.•Perfectionism and certainty obsessive beliefs improved treatment response.•Schemas related to dependency significantly mediated improvement in CT.•Specific cognitive changes precede behavioral symptom reduction in CT for OCD.

The present study aimed to identify mechanisms of change in individuals with moderately severe obsessive-compulsive disorder (OCD) receiving cognitive therapy (CT). Thirty-six adults with OCD received CT over 24 weeks. At weeks 0, 4/6, 12, 16/18, and 24, independent evaluators assessed OCD severity, along with obsessive beliefs and maladaptive schemas. To examine mechanisms of change, we utilized a time-varying lagged regression model with a random intercept and slope. Results indicated that perfectionism and certainty obsessive beliefs and maladaptive schemas related to dependency and incompetence significantly mediated (improved) treatment response. In conclusion, cognitive changes in perfectionism/certainty beliefs and maladaptive schemas related to dependency/incompetence precede behavioral symptom reduction for OCD patients. Targeting these mechanisms in future OCD treatment trials will emphasize the most relevant processes and facilitate maximum improvement.