Risk and Protective Factors for Suicide Mortality in Youths: A Systematic Review and Meta-Analysis.

Importance: Risk and protective factors for suicide mortality in youths remain poorly synthesized, as prior reviews have focused on all ages or nonfatal outcomes. Objective: To systematically assess factors associated with risk of suicide mortality in youths. Data Sources: MEDLINE, PsycINFO, Embase, and CINAHL from inception to March 7, 2025. Study Selection: Case-control and cohort studies of youths (aged ≤24 years) examining risk and/or protective factors associated with suicide mortality vs living general-population controls were included. Two independent reviewers screened 9497 records. Data Extraction and Synthesis: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 2 reviewers independently screened reports; 1 extracted data, verified by a second. Evidence was synthesized using vote counting and random-effects meta-analysis in April 2026. Main Outcomes and Measures: The primary outcome was suicide mortality at age 24 years or younger. Results: Ninety reports from 68 studies, mostly from high-income countries, identified distinct risk and/or protective factors; 54 reports contributed to 30 meta-analyses. The factors associated with the highest odds of suicide risk included schizophrenia (odds ratio [OR], 22.23; 95% CI, 12.05-41.03; I2 = 85.4%; 7 reports), mood disorders (OR, 11.32; 95% CI, 6.11-20.97; I2 = 64.6%; 7 reports), and self-harm (OR, 14.06; 95% CI, 5.58-35.39; I2 = 90.1%; 10 reports). Clinical indicators of health care use were also associated with higher risk, including mental health services use in preceding year (OR, 7.39; 95% CI, 6.45-8.47; I2 = 0.0%; 5 reports) and psychiatric admission (OR, 31.96; 95% CI, 13.83-73.86; I2 = 94.8%; 6 reports). At the socioecological level, several indicators were associated with higher risk, including maltreatment (OR, 4.03; 95% CI, 1.41-11.50; I2 = 67.1%; 5 reports), out-of-home placement (OR, 4.47; 95% CI, 2.15-9.28; I2 = 42.1%; 5 reports), youth justice system involvement (OR, 2.70; 95% CI, 1.94-3.75; I2 = 64.2%; 7 reports), and low educational attainment (OR, 2.95; 95% CI, 1.66-5.24; I2 = 76.0%; 5 reports). In contrast, indicators of family stability were associated with lower risk, including living with both parents (OR, 0.55; 95% CI, 0.48-0.62; I2 = 12.1%; 11 reports). Heterogeneity was substantial across analyses, while Newcastle-Ottawa ratings indicated moderate-to-high study quality. Conclusions and Relevance: In this systematic review and meta-analysis, suicide mortality in youths was associated with mental disorders, health care contact, and adversity, supporting both clinical care and population-level prevention, with future research needed in underrepresented populations.