In response to large numbers of senior center clients who suffer untreated depression and the dearth of geriatric mental health providers, the investigators have simplified Behavioral Activation to be delivered by lay volunteers ("Do More, Feel Better"; DMFB). The focus of Behavioral Activation is to guide clients to reengage in daily pleasant and rewarding activities, and reduce depressive symptoms. If the investigators can show that the lay delivery model has positive impact in comparison to MSW-delivered Behavioral Activation, the investigators will have identified an effective intervention that can be used by a large untapped workforce of older adult volunteers across the nation.

This Collaborative R01 application (UW, Cornell, USF) proposes to conduct an effectiveness trial of lay-delivered Behavioral Activation ("Do More, Feel Better"; DMFB), in comparison to MSW-delivered Behavioral Activation (MSW BA), for depressed (PHQ-9>10 and Ham-D>14) older (60+) senior center clients. The primary aim tests the effectiveness of DMFB, in comparison to MSW BA, on increasing overall activity level (target) and reducing depression symptoms. The investigators will test whether increased activity level predicts greater reduction in depression severity and whether increased activity's impact on depression is non-inferior across conditions. Secondarily, the investigators will test hypotheses associated with overall functioning, satisfaction with treatment, and client-level moderators. Lastly the investigators will explore longer-term client outcomes, delivery cost, and preparing for sustainability by exploring client, provider, and center factors related to intervention fidelity.

Client Participants (anticipated enrollment: 288)

Inclusion Criteria:

Referral to study (stage 1):

1. Age ≥ 60 years.
2. Attends one of 18 participating Seattle, NYC, or Tampa area senior centers.
3. Patient Health Questionnaire (PHQ-9) score of ≥10 via routine screening.

Research assessment (stage 2):

1. Clinically-assessed HAM-D>14
2. Mini-Mental Status Exam (MMSE) ≥ 24 OR modified Telephone Interview for Cognitive Status (mTICS) ≥ 19
3. Off antidepressants or on a stable dose for 12 weeks.
4. Capacity to provide written consent for both research assessment and the BA intervention.

Client Participants Exclusion Criteria:

1. Current active suicidal ideation.
2. Presence of psychiatric diagnoses other than unipolar, non-psychotic major depression or generalized anxiety disorder by SCID-V (Structure Clinical Interview for DSM-V).
3. Severe or life-threatening medical illness (e.g., end stage organ failure).
4. Inability to speak English or Spanish

Volunteer Participants (anticipated enrollment: 36) Inclusion Criteria

1. Age ≥ 60 years.
2. Attends one of the participating Seattle, NYC, or Tampa-area senior centers.

Volunteer Participants Exclusion Criteria

1. Current major depressive disorder, alcohol or substance abuse, or manic, hypomanic, or psychotic symptoms (SCID-V);
2. Mini-Mental Status Exam (MMSE) ≥ 24 OR modified Telephone Interview for Cognitive Status (mTICS) ≥ 19;
3. Inability to speak and read English or Spanish

Clinician Participants (anticipated enrollment: 36) Inclusion Criteria

1. Master's degree in social work, counseling, marriage/family, or other clinical mental health degree
2. English or Spanish Speaking
3. Capacity to provide consent for all study procedures
4. Willing to audio record study sessions for supervision and evaluation

Clinician Participants Exclusion Criteria

1. Non-English or Non-Spanish speaking
2. Does not hold a Master's degree in social work, counseling, marriage/family, or other clinical mental health degree
3. Unable to provide consent
4. Unwilling to audio record study sessions for supervision and evaluation

We will deposit participant data into the NIMH informatics infrastructure (e.g., National Data Archive) to enable sharing of clinical research data.