Autistic people within forensic psychiatric services and the criminal justice system: A systematic review

Understanding autism prevalence within the Criminal Justice System (CJS) and forensic settings has implications for identifying clinical/forensic needs, planning responses, potentially improving outcomes. This systematic review aimed to synthesise studies investigating autism prevalence within CJS/forensic cohorts, and the prevalence of CJS/forensic involvement in autistic cohorts. Searches were conducted on 6 June 2023, alongside backward searching and expert consultation. Studies were synthesised narratively with reporting quality appraised. The search yielded 6481 articles. Following duplicate removal, titles and abstracts of 4207 articles were screened; 71 articles were full text screened and 41 met eligibility criteria. Prevalence rates of autism in CJS/forensic settings were examined in 25 studies, varied from 0–60%, with rates of autism higher than the general population prevalence estimate of 1% in 24 of 25 included studies. Prevalence rates of CJS/forensic involvement in autistic populations were examined in 16 studies, with reported rates varying by 3–71%. Studies examining prevalence of CJS/forensic involvement among autistic people indicate a rate of offending at a lower, or equivalent level to comparison samples. However, studies examining autism prevalence within CJS/forensic settings suggest over-representation. Possible explanations fall within three categories: pre-sentencing factors, autistic offender factors or post-sentencing factors. Implications for practice and research are discussed.