Initiating and Maintaining Physical Activity in Depressed Individuals

The investigators propose a randomized clinical trial in which 240 depressed individuals are assigned to one of three arms, with each successive arm having an added component that may serve to increase and maintain physical activity: 1. brief advice (BA) to exercise (control condition); 2. BA + supervised \& home-based exercise (SHE)+health education (HE) contact control; and 3. BA+SHE+ cognitive-behavioral sessions focused on increasing and maintaining exercise (CBEX). There are two phases for participants: intervention phase (3 months), which consists of intensive contact, and the follow-up phase (6 months). BA will consist of one, 45-minute session about public health recommendations, and strategies for getting started. SHE will be a 12-week intervention consisting of 1x/week supervised exercise plus exercise prescriptions for home-based exercise with the goal of gradually achieving the public health recommendation of 150 minutes/week of moderate-to-vigorous physical activity (MVPA), CBEX and HE sessions will be individual, 30-minute, weekly sessions during the intervention phase. CBEX will address barriers to physical activity that are particularly pronounced in depression -i.e., anhedonia, decreased motivation, and decreased energy, as well as poor problem-solving skills. During the follow-up phase, groups who received SHE during the intervention phase will receive brief, monthly phone check-ins from an exercise specialist. Primary Aims: 1. To compare the efficacy of the 3 arms for increasing physical activity during the 12-week intervention phase. We hypothesize that BA + SHE + CBEX will be superior to BA + SHE + HE, and that BA + SHE + HE will be superior to BA alone in terms of objectively measured MVPA levels. 2. To compare the longer-term impact of the three arms on objectively-measured minutes of MVPA at 6- and 9-month follow-ups (i.e., follow-up phase). Hypotheses are the same as for the intervention phase (aim #1). Secondary Aims: 3. To assess the impact of proposed intervention combinations on depression, physical health outcomes including cardiorespiratory fitness and body composition, and self-reported MVPA in all phases. Hypotheses mirror those described in our primary aims above. 4. To determine whether amount of MVPA mediates the association between group assignment and change in depressive symptoms. We hypothesize that amount of MVPA will serve as a mediator. 5. To examine behavior change theory-based mediators of the association between group assignment and MVPA. Hypothesized mediators include: perceived benefits of exercise, perceived barriers to exercise, exercise self-efficacy, intrinsic motivation to exercise, and identified motivation to exercise. 6. To examine whether social and environmental barriers to exercise predict exercise maintenance.