Inlay

identified 41 articles for inclusion. Eligible studies consisted of randomized controlled trials that tested the effectiveness of peer support services for adults living with serious mental health challenges. We extracted and synthesized data on the competencies peer supporters demonstrated and implementation elements, including recruitment, training, supervision, and quality monitoring. Most studies were from high-income country settings, with the majority from the United States (75.6%). A competency taxonomy was developed based on the Substance Abuse and Mental Health Services Administration’s peer support core competencies guidelines, and through additional thematic content analysis. Out of the 16 peer support and clinical competencies identified, the most frequently deployed peer support competencies were collaboration and care (90%), providing support (83%), and communication (73%); the most frequently deployed clinical competency was mental health diagnosis and psychoeducation (51%). Peers were primarily recruited from community organizations. Although reports on training length and format were inconsistent, trainings were most often reported as in person and ranged from a few hours to 192 hours. Supervisors of peer supporters included more experienced peer supporters, clinicians, or other staff, and supervision consisted of reviewing quality ratings and providing feedback on specific cases. Our findings confirm the salience of a relatively small set of competencies across peer support interventions which could be considered universal for standardization and scaling up, as well as best practices for training and supervision. Future research should aim to identify additional competencies that are contextually sensitive or address the needs of vulnerable groups....