The objective of this study is to examine the mechanisms of action and outcome in mental health peer support groups. The study design is a randomized trial in which participants are assigned to one of three study arms: a recovery oriented mental health group led by peer facilitators (Vet-to-Vet), a recovery oriented group led by a clinician, or "treatment as usual." Qualitative and quantitative methods will be used to assess substantive content and process of the recovery groups, as well as mental health and recovery outcomes.