An evaluation and 20-year follow-up of a community forensic intellectual disability service.

Background: Since the middle of the 20th century, there have been several heterogeneous studies of recidivism by offenders with intellectual disabilities (ID) who have been in specialist mental health services after an index offence. Although some were long term, as befits a chronically needy group, laws and services have changed in that time. It may no longer be appropriate to rely on findings from the 1960s and 1970s.