Scales and screens. Apart from obtaining an accurate developmental history from a variety of sources, you can use rating scales and screening instruments, such as the Social and Communication Questionnaire10—although their utility is limited in adults. It is important not to risk overdiagnosis on the basis of these instruments alone: The gold standard of diagnosis remains clinical. The critical point is that the combination of core symptoms of social communication deficits and restricted interests is more important than the presence of a single symptom. A touch of oddity does not mean that one has ASD/AD.
Is the prevalence of violent crime increased in ASD/AD?
It is important to distinguish violent crime from aggressive behavior. The latter, which can be verbal or nonverbal, is not always intentional or malevolent. In some persons who have an intellectual disability, a desire to communicate might lead to inappropriate touching or pushing. This distinction is particularly relevant to psychiatrists because many people who have ASD have an intellectual disability.
Violent crime is more deliberate, serious, and planned. It involves force or threat of force. According to the Federal Bureau of Investigation Uniform Crime Reporting Program, violent crime comprises four offenses: murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault.11
Earlier descriptions of ASD/AD did not mention criminal violence as an important feature of these disorders. However, reports began to emerge about two decades ago suggesting that people who have ASD—particularly AD—are prone to violent crime. Some of the patients described in Wing’s original series12 of AD showed violent tendencies, ranging from sudden outbursts of violence to injury to others because of fixation on hobbies such as chemistry experimentation.
Reports such as these were based on isolated case reports or select samples, such as residents of maximum-security hospitals. Scragg and Shah, for example, surveyed the male population of Broadmoor Hospital, a high-security facility in the United Kingdom, and found that the prevalence of AD was higher than expected in the general population.13
Recent reports have not been able to confirm that violent crime is increased in persons with ASD, however:
- In a clinical sample of 313 Danish adults with ASD (age 25 to 59) drawn from the Danish Register of Criminality, Mouridsen and colleagues found that persons with ASD had a lower rate of criminal conviction than matched controls (9%, compared with 18%).14
- In a small community study, Woodbury-Smith and colleagues examined the prevalence rates and types of offending behavior in persons with ASD. Based on official records, only two (18%) had a history of criminal conviction.15
The role of psychiatric comorbidity
Psychiatric disorders are common in persons who have ASD. In one study, 70% of a sample of 114 children with ASD (age 10 to 14) had a psychiatric disorder, based on a parent interview.16 Although people with mental illness are not inherently criminal or violent, having an additional psychiatric disorder independently increases the risk of offending behavior.17 For example, the association of attention-deficit/hyperactivity disorder with criminality is well established.16 Some patients with severe depression and psychotic disorders, including schizophrenia, also are at increased risk of committing a violent act.
To examine the contribution of mental health factors to the commission of crime by persons with ASD, Newman and Ghaziuddin18 used online databases to identify relevant articles, which were then cross-referenced with keyword searches for “violence,” “crime,” “murder,” “assault,” “rape,” and “sex offenses.” Thirty-seven cases were identified in the 17 publications that met inclusion criteria. Out of these, 30% had a definite psychiatric disorder and 54% had a probable psychiatric disorder at the time they committed the crime.18
Any patient with ASD/AD who is evaluated for criminal behavior should be screened for a comorbid psychiatric disorder. In adolescents, stressors such as bullying in school and problems surrounding dating might contribute to offending behavior.
What are management options in the face of violence?
Managing ASD/AD when an offending behavior has occurred first requires a correct diagnosis.19 Professionals working in the criminal justice system have little awareness of the variants of ASD; a defendant with an intellectual disability and a characteristic facial appearance (for example, someone with Down syndrome) can be easily identified, but a high-functioning person who has mild autistic features often is missed. This is more likely to occur in adults because the symptoms of ASD, including the type and severity of isolated interests, change over time.
Here is how I recommend that you proceed:
Step #1. Confirm the ASD diagnosis based on developmental history and the presence of persistent social and communication deficits plus restricted interests.