Social connection interventions and depression in young adults: a systematic review and meta-analysis

Early adulthood is a period which may increase vulnerability to loneliness and mental health difficulties among young adults. Social networks play an important role in buffering against adverse mental health, but there is a lack of evidence around whether social connection interventions could play a role in preventing mental health difficulties for young adults. A systematic review and meta-analysis was conducted (PROSPERO ID: CRD42023395595). PubMed, PsycInfo, and Scopus were searched (01 January 2000-01 January 2023). Studies were eligible if they (i) were quantitative, (ii) included young adults (18-24 years) from the general population, (iii) tested a social intervention which aimed to increase the quantity or quality of social connections or reduce loneliness, (iv) had a comparison group, and (v) measured depression and loneliness/social connection as outcomes. Following study screening and selection, the data extraction and risk of bias assessments were independently conducted in duplicate. The Cochrane RoB-2 tool and ROBINS-I tool were used to assess risk of bias. Results were narratively synthesised and random effects meta-analysis with standardised mean differences was conducted. Six studies were included; four in-person interventions with higher education students, one online intervention with higher education students, and one intervention for youth involved in street life. The studies were mostly rated as having some or moderate concerns with risk of bias. The interventions were associated with an overall mean reduction in depression for young adults (SMD = -0.19; 95% CI, -0.33 to -0.05; p = 0.008; 4 studies, excluding studies with serious risk of bias). All interventions had beneficial effects on a range of diverse social connection outcomes, but there was no overall statistically significant mean reduction in loneliness for young adults in pooled analyses (SMD = -0.10; 95% CI, -0.24 to 0.05; p = 0.188; 3 studies). Social connection interventions show some promise in improving depression and social connection outcomes in young adults but more high-quality research, across diverse settings, is needed in this area.