Objective: Obsessive-compulsive disorder (OCD) is associated with impaired functioning and depression. Our aim was to examine relationships between OCD symptoms, depression and functioning before and after exposure and response prevention (ERP), a type of cognitive-behavioural therapy for OCD, specifically examining whether functioning, depression and other cognitive factors like rumination and worry acted as mediators.
Methods: Forty-four individuals with OCD were randomised to 4 weeks of intensive ERP treatment first (n = 23) or waitlist then treatment (n = 21). We used a bootstrapping method to examine mediation models.
Results: OCD symptoms, depression and functioning significantly improved from pre- to post-intervention. Functioning mediated the relationship between OCD symptoms and depression and the relationship between functioning and depression was stronger at post-treatment. Depression mediated the relationship between OCD symptoms and functioning, but only at post-intervention. Similarly, rumination mediated the relationship between OCD symptoms and depression at post-intervention.
Conclusions: Our findings suggest that after ERP, relationships between depression and functioning become stronger. Following ERP, treatment that focuses on depression and functioning, including medication management for depression, cognitive approaches targeting rumination, and behavioural activation to boost functionality may be important clinical interventions for OCD patients.
Keywords: Cogntive-behavioural therapy; depression; global functioning; mediation; obsessive-compulsive disorder.