The association between positive outcome expectancies and avoidance in predicting the outcome of cognitive behavioural therapy for major depressive disorder

Although cognitive behavioural therapy (CBT) is an empirically supported treatment for major depressive disorder (MDD), individual differences in the effectiveness of CBT have been observed. Preliminary evidence suggests that positive outcome expectancies for treatment predict better therapy outcomes (Constantino, Arnkoff, Glass, & Smith, 2011); however, researchers have not examined whether avoidance, an important predictor of depressive symptoms (Ottenbreit & Dobson, 2004), may play an important role in this association. In the present study, we examined whether the association between positive outcome expectancies and therapy outcome is associated with patients' levels of avoidance.

Data were collected as part of a prospective, longitudinal study.

The sample consisted of 51 patients diagnosed with MDD who underwent CBT. Prior to treatment, clinicians rated patients on their levels of avoidance and positive outcome expectancies. A self-report rating of positive outcome expectancies was also obtained, and the Beck Depression Inventory (BDI-II; Beck, Steer, & Brown, 1996) was completed pre- and post-treatment. A hierarchical regression analysis was conducted to examine the association between positive outcome expectancies and avoidance for predicting changes in depressive symptoms after CBT.

For patients with lower levels of positive outcome expectancies, lower levels of avoidance predicted greater improvement after CBT and higher levels of avoidance predicted poorer treatment outcomes.

These findings suggest that the impact that lower positive outcome expectancies have on therapy outcome can be attenuated if patients do not avoid dealing with emotionally difficult material in session.