Affect following first exercise session as a predictor of treatment response in depression

Objective: Remission rates are low with first-step or even second-step antidepressant treatments. Furthermore, despite extensive investments from National Institutes of Health and from industry, novel treatments are not yet available in clinical care for depression. Predictors of treatment response very early in the course of treatment can avoid unnecessarily lengthy trials with ineffective treatments and reduce the trial and error process. This article examines the expression of positive affect immediately following an acute exercise session at the end of the first exercise session as a predictor of treatment response in the National Institute of Mental Health-funded TREAD (Treatment with Exercise Augmentation for Depression) study, which was conducted from April 2003 to August 2007. Methods: 122 subjects with DSM-IV-diagnosed major depressive disorder were randomized to public health dose (16 kcal/kg/wk) or low dose (4 kcal/kg/wk) of exercise for 12 weeks. Affect following the first exercise session was assessed using the Positive and Negative Affect Scale (PANAS), and depressive symptoms were assessed weekly using the Inventory of Depressive Symptomatology, Clinician Rating (IDS-C) (primary outcome measure). Results: The PANAS composite affect score (positivenegative total) predicted change in IDS-C score (P < .05), as well as treatment response (P < .02) and remission (P < .03) for those in the high-dose group but not in the low-dose group. Conclusions: These findings suggest that the composite positive affect following the first exercise session has clinical utility to predict treatment response to exercise in depression and match the "right patient" with the "right" treatment.