Abstract Follow-up studies of patients discharged to the community from the English Special Hospitals were reviewed. Differences in reconviction rates between patients conditionally and absolutely discharged and between those classified as mentally ill (MI) and psychopathically disordered (PD) were identified. The cases of the first 106 male patients discharged from Park Lane Hospital were examined. Details of their clinical features and criminological history were analysed. During the follow-up period of between 6 months and 14 years, 87 of the patients had not been convicted of a serious offence. Clear and consistent differences in reconviction rates were found; patients classified as psychopathically disordered were significantly more likely to be reconvicted than those classified as mentally ill and those who were subject to conditions after discharge were reconvicted significantly less often than those who were discharged without conditions. Virtually all of the reconvictions of the mentally ill grou...