Offenders with intellectual disability: the size of the problem and therapeutic outcomes

People with intellectual disability (ID) who offend may be subject to a variety of dispositions within the criminal justice system, or via diversion to health and social services in inpatient units or in community ID teams. Offenders with ID are a group with complex needs who may pose a recurrent risk to the public. Despite the significant number of offenders with ID, there is limited evidence on treatment effectiveness and outcomes.

A literature search of all electronic databases was undertaken, and journals were hand-searched for clinical trials or case studies of interventions for offenders with ID. The main outcome was recidivism rates.

There were no published clinical trials of offenders with ID. A series of small-scale group cognitive-behavioural treatments for sex offenders offers the most persuasive evidence of success in reducing recidivism.

Offenders with ID often receive inadequate services as a result of poor identification through the criminal justice system and research into effective treatments is rudimentary. Further studies are necessary in order to improve treatment efficacy and service provision for a complex group of individuals.