Mental disorders in Australian prisoners: a comparison with a community sample.

BACKGROUND: The plight of those with mental health problems and the possible role of prisons in "warehousing" these individuals has received considerable media and political attention. Prisoners are generally excluded from community-based surveys and to date no studies have compared prisoners to the community. OBJECTIVE: The objective was to examine whether excess psychiatric morbidity exists in prisoners compared to the general community after adjusting for demographics. METHOD: Prison data were obtained from a consecutive sample of reception prisoners admitted into the state's correctional system in 2001 (n = 916). Community data were obtained from the 1997 Australian National Survey of Mental Health and Wellbeing (n = 8168). Mental health diagnoses were obtained using the Composite International Diagnostic Interview and a number of other screening measures. Weighting was used in calculating the 12-month prevalence estimates to control for demographic differences between the two samples. Logistic regression adjusting for age, sex and education was used to compare the prison and community samples. RESULTS: The 12-month prevalence of any psychiatric illness in the last year was 80% in prisoners and 31% in the community. Substantially more psychiatric morbidity was detected among prisoners than in the community group after accounting for demographic differences, particularly symptoms of psychosis (OR = 11.8, 95% CI 7.5-18.7), substance use disorders (OR = 11.4, 95% CI 9.7-13.6) and personality disorders (OR = 8.6, 95% CI 7.2-10.3). Mental functioning and disability score were worse for prisoners than the community except for physical health. CONCLUSIONS: This study found an overrepresentation of psychiatric morbidity in the prisoner population. Identifying the causes of this excess requires further investigation.