LAUSR

Abstract Although exposure and response prevention (ERP) is the first line psychological treatment for individuals with obsessive compulsive disorder (OCD), many people experience partial recovery and others refuse treatment or drop out. This randomized controlled study (n= 40) examined the effect of a three-session motivational interviewing (MI) intervention compared to a three-session relaxation intervention prior to 15 sessions of ERP on treatment dropout, homework compliance, and treatment outcome post-ERP and at follow up. Contrary to hypotheses, there were no group differences in ERP dropout rates or homework compliance. Both groups experienced significant reductions in OCD symptoms post-ERP. Consistent with our hypothesis, the MI group experienced a greater reduction in OCD symptoms (clinician-rated YBOCS) compared to the comparison group immediately post-ERP. However, this difference did not hold over 12-month follow up. There were also no group differences in associated symptoms (depression, anxiety, stress) across treatment. All participants achieved significant symptom reductions that were maintained over time. A correlational analysis of the whole sample revealed that action scores pre-ERP were significantly negatively correlated with post-ERP OCD symptom severity. These findings suggest that MI prior to ERP may confer a small but meaningful benefit for enhancing treatment outcome post ERP.