To access, purchase, authenticate, or subscribe to the full-text of this article, please visit this link: http://dx.doi.org/10.1016/j.jocrd.2018.05.001 Byline: Hannah C. Levy [email@example.com] (a,*), Scott E. Hannan (a), Gretchen J. Diefenbach (a,b), David F. Tolin (a,b) Keywords Inhibitory cognitive change; Piecewise linear growth modeling; OCD; Beliefs; Exposure Highlights * Change in maladaptive beliefs may be important for successful treatment outcomes. * We compared belief change in self-directed and therapist-directed exposure for OCD. * Results demonstrated greater belief change in the therapist-directed condition. * It may be helpful to add cognitive training to self-directed exposure protocols. Abstract Self-directed treatment may be a cost-effective adjunctive or stand-alone intervention for obsessive-compulsive disorder (OCD) and related problems. Current cognitive-behavioral theories suggest that disconfirmation of maladaptive beliefs about feared stimuli is a mechanism of change in exposure-based treatments. It is unclear whether self-directed exposure therapy results in the same degree of change in maladaptive beliefs as traditional therapist-directed exposure. The current study used data from a published trial of self-directed and therapist-directed exposure therapy for OCD (N = 41; Tolin et al., 2007) to compare change in obsessive beliefs between the two treatments. The original trial found superior treatment outcomes for patients in the therapist-directed condition as compared to the self-directed condition. Piecewise linear growth modeling demonstrated that therapist-directed exposure resulted in greater change in obsessive beliefs from pre-treatment through 6-month follow-up than did self-directed treatment. Post-treatment obsessive beliefs mediated post-treatment OCD symptoms in both treatment conditions, suggesting that treatment effects were at least in part due to change in obsessive beliefs. The findings suggest that therapist-directed exposure leads to greater cognitive change than does self-directed treatment, and are discussed in terms of cognitive-behavioral theory and potential ways to promote belief change in therapist- and self-directed treatment. Author Affiliation: (a) Anxiety Disorders Center, Institute of Living/Hartford Hospital, 200 Retreat Avenue, Hartford, CT 06106, United States (b) Department of Psychiatry, Yale University School of Medicine, 300 George Street, New Haven, CT 06511, United States * Corresponding author. Article History: Received 21 March 2018; Revised 24 April 2018; Accepted 1 May 2018 (footnote)[white star] Author Note. This work was supported by the Patrick and Catherine Weldon Donaghue Medical Research Foundation (01-022). No other declarations of interest.