RecruitingBehavioural interventionLay-Delivered Behavioral Activation in Senior CentersIn 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.