OBJECTIVE: The complexity of psychotherapies has been a barrier to community implementation. We used the Research Domain Criteria consensus as a guide to develop Engage, a streamlined, neurobiology-based psychotherapy for late-life depression that may match the skill set of practicing clinicians. This proof of concept study tested the hypotheses that Engage is bioequivalent to Problem Solving Therapy (PST) in reducing depressive symptoms, inducing remission, and ameliorating disability.

METHODS: Engage assumes that abnormal function of the positive valence systems fuels depression and uses "reward exposure" (engagement in meaningful, rewarding activities) as its principal intervention. Negativity bias, apathy, and emotional dysregulation are expressions of abnormalities in the negative valence, arousal and regulatory, and cognitive control systems, respectively. Engage targets each of them with simple interventions only if they interfere with reward exposure. We treated openly, with 9 weekly sessions of Engage, 39 older adults with unipolar major depression. We compared their course of depression (HAM-D), remission rate (HAM-D<10), and disability (WHODAS) with those of a historical comparison group (N = 97) treated with 9 weekly sessions of PST.

RESULTS: Community social workers and research therapists required one third as much training time in Engage as in PST. Engage was non-inferior to PST in reducing HAM-D and WHODAS. Remission rates for Engage at 6 and 9 weeks were 18.2% and 41.1%, respectively. The corresponding figures for PST were 13.7% and 35.0%, respectively.

CONCLUSION: These initial observations suggest that Engage has comparable efficacy with PST in reducing depressive symptoms and disability and warrants a randomized controlled trial.