Assessing BDNF as a mediator of the effects of exercise on depression

Abstract Brain-derived neurotrophic factor (BDNF) is associated with neuronal growth and reduced BDNF has been implicated in depression. A recent meta-analysis documented reliable effects of exercise on BDNF levels (Szuhany et al., 2015); although, few studies included participants with mental health conditions. In this study, we examine whether increased exercise was associated with enhanced BDNF response in depressed patients, and whether this change mediated clinical benefits. A total of 29 depressed, sedentary participants were randomized to receive either behavioral activation (BA) plus an exercise or stretching prescription. Blood was collected prior to (resting BDNF levels) and following an exercise test (pre-to post-exercise BDNF change) at four points throughout the study. Participants also completed depression and exercise assessments. BDNF increased significantly across all assessment points (p  Clinical Trials Registry (clinicaltrials.gov) NCT02176408 , “Efficacy of Adjunctive Exercise for the Behavioral Treatment of Major Depression”.