The relationship between positive affect and negative affect during treatment for major depressive disorder

Objective: The present study examined the relationship between positive affect (PA) and negative affect (NA) along the course of combined cognitive behavior therapy and pharmacological treatment for major depressive disorder (MDD). Method: Participants were 165 individuals who sought treatment for MDD in a partial hospital setting. Participants' PA, NA, and depressive symptoms were measured at pre- and post-treatment and PA and NA were measured at up to 10 additional measurements along the course of treatment. Results: Results indicated that PA at pre-treatment predicted depressive symptoms at post-treatment above and beyond NA and the PA*NA interaction. However, an analysis of patterns of change during treatment using lower level mediational modeling in a multilevel framework indicated that NA predicted subsequent PA to a greater extent than vice versa. Conclusion: Though many treatments for MDD predominantly focus on reducing NA, our findings suggest that PA may be an important predictor of outcome in treatment for MDD, and that the inclusion of interventions to increase the experience of PA may help improve the efficacy of treatment.