Lifestyle interventions for weight loss among overweight and obese adults with serious mental illness: A systematic review and meta-analysis.

Objective: To conduct a systematic review and meta-analysis to estimate effects of lifestyle intervention participation on weight reduction among overweight and obese adults with serious mental illness.

Method: We systematically searched electronic databases for randomized controlled trials comparing lifestyle interventions with other interventions or usual care controls in overweight and obese adults with serious mental illness, including schizophrenia spectrum or mood disorders. Included studies reported change in weight [kg] or body mass index (BMI) [kg/m] from baseline to follow-up. Standardized mean differences (SMD) were calculated for change in weight from baseline between intervention and control groups.

Results: Seventeen studies met inclusion criteria (1968 participants; 50% male; 66% schizophrenia spectrum disorders). Studies were grouped by intervention duration (≤6-months or ≥12-months). Lifestyle interventions of ≤6-months duration showed greater weight reduction compared with controls as indicated by effect size for weight change from baseline (SMD=-0.20; 95% CI=-0.34, -0.05; 10 studies), but high statistical heterogeneity (I=90%). Lifestyle interventions of ≥12-months duration also showed greater weight reduction compared with controls (SMD=-0.24; 95% CI=-0.36, -0.12; 6 studies) with low statistical heterogeneity (I=0%).

Conclusion: Lifestyle interventions appear effective for treating overweight and obesity among people with serious mental illness. Interventions of ≥12-months duration compared to ≤6-months duration appear to achieve more consistent outcomes, though effect sizes are similar for both shorter and longer duration interventions.