Prospective cohort study of mental health during imprisonment.

BACKGROUND Mental illness is common among prisoners, but little evidence exists regarding changes in symptoms in custody over time. AIMS To investigate the prevalence and predictors of psychiatric symptoms among prisoners during early custody. METHOD In a prospective cohort study, 3079 prisoners were screened for mental illness within 3 days of reception. To establish baseline diagnoses and symptoms, 980 prisoners were interviewed; all remaining in custody were followed up 1 month and 2 months later. RESULTS Symptom prevalence was highest during the first week of custody. Prevalence showed a linear decline among men and convicted prisoners, but not women or remand prisoners. It decreased among prisoners with depression, but not among prisoners with other mental illnesses. CONCLUSIONS Overall, imprisonment did not exacerbate psychiatric symptoms, although differences in group responses were observed. Continued discussion regarding non-custodial alternatives for vulnerable groups and increased support for all during early custody are recommended.