The goal of this project is to train community mental health therapists in behavioral activation (BA) treatment for major depressive disorder and then to conduct a study examining the feasibility of evaluating the effectiveness of BA in this setting.

After finalizing a 9-session BA treatment model for major depressive disorder in the Community Mental Health Center (CMHC) setting, the final treatment manual will be used to train clinicians in BA at the CMHC through workshops and training cases.

Upon completion of training and certification of adequate implementation of BA, a total of 80 patients with MDD will be randomly assigned in a 3:1 ratio to 9 sessions of BA or treatment-as-usual (TAU) at the CMHC. Feasibility will be assessed in terms of (1) percent of eligible patients who refuse randomization, (2) percent of patients who complete 9 sessions of BA treatment, (3) percent of BA homework assignments that are completed, (4) percent of monthly assessments obtained, and (5) patient ratings of credibility and alliance in BA treatment. The ability of CMHC therapists to adequately implement BA will be assessed by rating taped sessions on BA adherence and competence scales. In addition to feasibility/acceptability of BA and TAU, this study is designed to test whether theoretically important targets of BA change over the course of BA treatment, and whether such changes are associated with changes in depressive symptoms. The target measures will be assessed at baseline, month 1, month 2, and month 3. To support the potential role of these targets as the mechanisms of change in BA, change in the target variables will be examined in relation to change in depression symptoms. The investigators will also pilot a potential moderator of treatment effects (trait reward processing, as measured at baseline using the Effort-Expenditure for Rewards Task) to include this potential moderator in a subsequent fully-powered study with the long-term goal of identifying the types of patients most responsive to BA.

Inclusion Criteria:

1. confirmed diagnosis of MDD based on the SCID for DSM-IV (or DSM-V, if available),
2. ability to read at least at the 4th grade level,
3. willingness to participate in research,
4. willingness to be audio recorded (for both therapists and patient- participants)

Exclusion Criteria:

1. current or past psychotic disorder, seizure disorder, or clinically significant organic pathology
2. acute medical problem requiring immediate inpatient treatment,
3. current substance abuse or dependence requiring primary referral to substance abuse program,
4. significant suicidal risk/ideation requiring immediate referral or suicidal gesture within the last 3 months

Data will be shared via the Research Domain Criteria Database (RDoCdb), part of the NIMH Data Archive (NDA). All feasibility and outcome data will be shared.