The Prevalence of Obstructive Sleep Apnoea in Schizophrenia, Bipolar Disorder and Major Depressive Disorder: A Systematic Review With Meta‐Analysis

INTRODUCTION: People with severe mental illness (SMIs) are at an increased risk of morbidity and reduced life expectancy. Obstructive sleep apnoea (OSA), a prevalent but underdiagnosed condition in SMIs, may precipitate more physical health complications. This meta-analysis aimed to estimate the prevalence of OSA and assess its risk in SMIs populations. METHODS: We conducted a systematic review and meta-analysis on studies reporting either diagnosis or high risk of OSA in bipolar disorder (BD), schizophrenia (SCZ), and major depressive disorder (MDD). Databases were searched through January 2026. Pooled prevalence of OSA was calculated through a single-group meta-analysis, while odds ratios (ORs) comparing SMIs and control groups were estimated by a two-group meta-analysis. RESULTS: A total of 47 articles were included in the meta-analysis. The pooled prevalence of OSA in SMIs was 41.2%, largely influenced by clinical and sleep-referral settings, with a 38.3% prevalence in SCZ, 38.2% in MDD and 35.6% in BD. Compared to healthy controls (HCs) without psychiatric diagnosis, participants with SMIs had significantly higher odds of being diagnosed with OSA (OR = 6.96; 95% CI = 2.48, 19.51; k = 2; p-value < 0.001). High risk of OSA was present in 46.7% of SMI individuals. BD participants showed significantly higher excessive daytime sleepiness compared to HCs (SMD = 0.63; 95% CI = 0.28, 0.98; k = 2; p-value < 0.001). CONCLUSION: People with SMIs have a high prevalence of OSA and are at an increased risk of OSA compared to the general population. These findings highlight the considerable burden of OSA in SMIs and support the need for systematic assessment within psychiatric care settings.