Risk factors of violent offending in mentally ill prisoners with autism spectrum disorders

Background
Results of research regarding a possible causal relation between autism spectrum disorders (ASDs) and violence are mixed. Several explanations have been proposed.

Aims
To assess prevalence rates of comorbid disorders in a large sample of mentally ill offenders diagnosed with ASD. Offenders with and without comorbid mental disorders were compared on several characteristics. To better understand the relationship between ASD and violent criminal behavior, the predictive value of several proposed risk factors (comorbidity, negative social network/influenceability, and childhood trauma/victimization) on violent offending was investigated.

Method
Data of 394 male offenders with a diagnosis of ASD were included. Prevalence rates of comorbid mental disorders next to ASD were calculated, and characteristics were compared using chi-square or t-tests. The predictive value of the risk factors was assessed using a binary logistic regression (n = 357).

Results
High rates of comorbidity were found (78.9%), specifically for substance use disorders (39.8%), schizophrenia spectrum disorders (31.7%), and neurodevelopmental disorder other than ASD (24.1%). Offenders with and without comorbidity differed significantly in their criminal and mental health care history. Both comorbidity (OR = 1.68; 95% CI 1.27–2.18) and a negative social network/influenceability (OR = 1.49; 95% CI 1.11–1.99) showed to be significant predictors of violent offending within this sample.

Conclusions
The highest rates of comorbid disorders found were disorders that have been previously linked to violent offending, and the risk of violent offending could be unrelated to ASD. However, the role of social functioning indicates a risk specific to the symptoms of ASD.