Offence type and neurodiversity: A comparison of 12-17-year-old boys charged with a criminal offence by diagnosis of autism spectrum disorder, attention deficit hyperactivity disorder or both.

Background: Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) have been evidenced as common among adolescents with delinquent behaviour. Less is known, however, about the relationship between these disorders and type of alleged offence, when the adolescent is involved with the criminal justice system.

Aim: Our aim was to investigate whether the type of alleged index offences among 12-17-year-olds differ between those diagnosed with ASD, ADHD or ASD + ADHD.

Method: The sample was selected for ASD and/or ADHD diagnoses from a database of all pre-trial forensic psychiatric and psychological assessments of male adolescents of 12-17 years old in the Netherlands for the years 2013 and 2014. For each record, independent researchers scored a 76-item checklist encompassing health and offending characteristics. Sixty-nine of the 1799 pre-trial assessments of these male adolescents had a diagnosis of ASD, 90 of ADHD and 29 had been diagnosed with both; these 188 cases formed our sample.

Results: The rate of sex offences was significantly higher among those with ASD (N = 20, 29%) than those with ADHD (N = 10, 11%) or both (N = 4, 14%; Fisher's exact test = 8.54; p = 0.014). By contrast, the rate of property offences without violence was significantly higher among those with ADHD (N = 22, 24%) than those with ASD (N = 4, 6%) or both (N = 5, 17%; Fisher's exact test = 10.50, p = 0.004), whereas violent offending rates did not differ between the three groups.

Conclusion: Specific offence types were not equally distributed among male adolescents with different psychiatric diagnoses. In our sample of male adolescents suspected of an offence nearly one-third of those diagnosed with ASD were convicted of a sex offence, suggesting highly specialised needs for further assessment and intervention. Among those diagnosed with ADHD, significantly more adolescents were charged with non-violent property offences. Such unequal distribution of alleged offence types among adolescents with different psychiatric diagnoses justifies tailor-made attention for offending adolescents with different psychiatric diagnoses.