Digital peer support interventions for people with mental health conditions in outpatient settings: a systematic review and meta-analysis

Background Mental health conditions are a major global challenge with rising demand for accessible, effective, scalable treatments. Digital peer support interventions are a promising way to extend support beyond clinical settings, but their effectiveness requires comprehensive evaluation. Objective To evaluate the effectiveness of digital peer support interventions in improving clinical symptoms, functioning, and treatment engagement among individuals with mental health conditions in outpatient settings. Study selection and analysis We conducted a systematic review and random-effects meta-analysis of controlled interventional studies. Five databases (MEDLINE, CENTRAL, Embase, PsycINFO) were searched up to January 2025. Studies evaluated digital peer support via online platforms, mobile apps or digital communities for people aged ≥16 years with mental health conditions. Outcomes included clinical symptoms (depression, anxiety), functioning (quality of life, social functioning) and treatment engagement. Risk of bias was assessed using Cochrane Risk of Bias 2.0 for randomised controlled trials and ROBINS-I for non-randomised studies. Certainty of evidence was assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation). Findings 29 studies including 5825 participants were included. Digital peer support was associated with small-to-moderate improvements in symptoms of depression (standardised mean difference (SMD) −0.28; 95% CI −0.42 to −0.14) and anxiety (SMD −0.47; 95% CI −0.68 to −0.27). Functional outcomes improved modestly: social functioning (SMD 0.18; 95% CI 0.07 to 0.29), quality of life (SMD 0.14; 95% CI 0.02 to 0.26), patient activation (SMD 0.39; 95% CI 0.23 to 0.55) and personal recovery (SMD 0.23; 95% CI 0.11 to 0.35). No significant effects were observed for treatment engagement or satisfaction. Preliminary evidence suggested sustained benefits for depression, anxiety and social functioning. Conclusions and clinical implications Digital peer support offers modest improvements in symptoms and functioning for individuals with mental health conditions and may be considered as an adjunct to usual care to enhance engagement and provide accessible support between clinical contacts. Key priorities include establishing optimal intervention models, clarifying longer-term benefits, and ensuring these approaches can be delivered safely and sustainably within routine outpatient services. PROSPERO registration number CRD42023445194.