Prevalence of mental disorders among people who are homeless: an umbrella review

Introduction: Homelessness is a major problem that critically impacts the mental health and wellbeing of the affected individuals. This umbrella review aimed to evaluate the current evidence on the prevalence of mental disorders among homeless people from evidence-based systematic reviews and meta-analyses. Methods: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Joanna Briggs Institute (JBI) methodology for umbrella reviews. We searched 12 major databases and additional sources to identify systematically conducted reviews and meta-analyses reporting the prevalence of mental disorders among homeless populations. Results: We evaluated 1,277 citations and found 15 reviews meeting our criteria. Most studies were conducted among high-income countries with samples from different age groups. Studies reported high prevalence rates of depressive and anxiety disorders, schizophrenia spectrum and psychotic disorders, substance use disorders, suicidal behavior, bipolar and mood disorders, neurocognitive disorders, and other mental disorders among homeless people. Moreover, studies also reported a high burden of co-occurring mental and physical health problems among the homeless experiencing mental disorders. Conclusions: This umbrella review synthesized the current evidence on the epidemiological burden of mental disorders in homelessness. This evidence necessitates advanced research to explore psychosocial and epidemiological correlates and adopt multipronged interventions to prevent, identify, and treat mental disorders among homeless populations.