Prevalence of mental disorders in Australian custodial settings: a systematic review and meta-analysis

Introduction People in custody face a greater burden of mental disorders than the general population. To our knowledge, there has been no national synthesis of the prevalence of mental disorders among people incarcerated in Australian prisons and youth detention settings. Methods We searched eight electronic databases from inception to October 7, 2025, for studies reporting the prevalence of mental disorders (including mental, behavioural, neurodevelopmental, and substance use disorders) among people incarcerated in Australian prisons or youth detention. We conducted random-effects meta-analyses to estimate pooled prevalence by diagnostic group and specific diagnosis, stratified by custodial setting. We conducted subgroup meta-analyses by sex and Indigenous status. We explored sources of heterogeneity through subgroup analyses when at least three studies were available. Results We identified 58 articles reporting data on 36,531 people (aged 16–90) incarcerated in Australian prisons, and 1,629 young people (aged 10–22) in youth detention. Half of people incarcerated in prisons (50.5% [95%CI 39.9–61.2]; I 2 = 99.6; k = 13) and almost three-quarters of young people in youth detention (73.4% [48.8–92.1]; I 2 = 98.5; k = 4) met the criteria for any current or lifetime mental disorder. In prison samples, prevalence estimates across diagnostic subcategories ranged from 7.5% (95%CI 4.4–11.3; I 2 = 97.13; k = 8) for current or lifetime schizophrenia to 48.2% (31.5–65.0; I 2 = 99.1; k = 6) for current or lifetime substance use disorder. In youth detention, prevalence estimates ranged from 5.8% (95%CI 1.1–13.4; I 2 = 92.0; k = 3) for any current or lifetime psychotic disorder to 70.7% (32.2–97.2; I 2 = 98.5; k = 3) for 12-month conduct disorder. In subgroup analyses, women, particularly First Nations women, incarcerated in prisons had a higher prevalence of mental disorders than both men overall and First Nations men, across most diagnostic categories. Conclusions These findings underscore the need for increased investment in gender-responsive, culturally-safe, and trauma-informed mental health screening and care in custody, and improved continuity of care between custodial and community settings.