Autism Spectrum Disorders and Criminal Convictions: The Role of Psychiatric Comorbidity

Background:  The literature related to criminal offending in individuals with autism spectrum disorders (autism) is inconsistent. It is still unclear whether individuals diagnosed with autism are more likely to engage in, or be convicted for criminal activity. Importantly, there is little information on potentially modifiable factors, such as psychiatric co-morbidity, that may help identify individuals at high risk of criminal activity and inform preventative strategies.

Objectives:  To test the following hypotheses: 1) that individuals with autism are more likely to receive a criminal conviction than the general population in Sweden, and 2) that potentially treatable psychiatric co-morbidities may be important factors that modify this risk.

Methods:  Longitudinal population-based study based on a record-linkage cohort of all non-adopted singletons in Sweden born between 1984 and 1995 with data on both biological parents and at least 15 years (the age of criminal responsibility in Sweden) follow up until 31 December 2011 (n=1,339,255 including n=15,368 with autism). Unique personal identification numbers were used to link data with the National Crime Register and other Swedish health and administrative registers leading to an information rich cohort with extensive data. After testing the proportional hazards assumption, the risks of criminal convictions in individuals with autism compared with those without were estimated using Cox proportional hazards regression models. The models were adjusted for various individual and family level socioeconomic and demographic characteristics. 

Results:  Individuals with autism appeared to be at a higher risk of having criminal convictions than those without [Hazard Ratio (HR) 1.31, 95% Confidence Interval (CI) 1.26-1.37]. However, stratifying the risk estimates by a recorded history of co-morbid psychiatric diagnosis revealed that: as compared to individuals without a diagnosis of autism or psychiatric conditions, individuals with autism with a psychiatric co-morbidity were more likely [adjusted HR 1.45 95% CI (1.39-1.52)], but those with autism without a co-morbid psychiatric diagnosis were less likely [adjusted HR 0.59 95% CI (0.51-0.67)] to be convicted for a criminal offence in Sweden. Further analyses on the types of criminal activity (e.g. convictions for violent vs. non violent crimes) and the role of individual co-morbidities (e.g. ADHD, conduct disorder, psychotic disorders) is underway and will be presented at the meeting. 

Conclusions:  These preliminary results suggest that co-morbid psychiatric conditions may be a major factor in relation to the risk of criminal offending in individuals with autism.