The Intellectually Disabled Offender: Methodological Problems in Identification

Abstract

Background Reliable evidence concerning the prevalence of intellectually disabled offenders that would inform the clinician's approach to the assessment and management of risk is in short supply. This paper aims to assist the clinician in interpreting the available evidence. Methods A literature search was conducted for all years up to January 2003. Each study was first examined for the methods employed to define and measure intellectual disability. Then, the effect of this on prevalence estimates was considered. Results A wide range of methods has been used to ascertain the presence of intellectual disability – administrative definitions, psychiatric diagnosis, educational background, self‐report and direct measurement of IQ and adaptive behaviour. Conclusions Most studies reviewed used less than adequate ascertainment methods. Reliable answers to two key questions – which offenders have intellectual disabilities and which people with intellectual disabilities offend – therefore remain elusive.