SEATTLE -- Individuals with Asperger's syndrome seldom commit crimes, experts said at the annual meeting of the American Academy of Psychiatry and the Law. But when they do, definitively diagnosing the disorder and mounting a legal defense can prove challenging.
"There is some suggestion that a small minority of people with autism may engage in problematic behaviors, and that may lead them into coming into contact with the criminal justice system," said Dr. Marc Woodbury-Smith, who is affiliated with the department of psychiatry and neurosciences at McMaster University, Hamilton, Ont.
For example, people with Asperger's syndrome comprise 1.5%-4.8% of criminal offenders detained in maximum-security psychiatric hospitals.
And estimates suggest that perhaps 0.02%- 2.0% of affected individuals in the community exhibit violence or another problematic behavior.
The types of offenses committed by people with Asperger's are noteworthy for their diversity, Dr. Woodbury-Smith said. They include vandalism, inappropriate touching, theft, indecent assault, and manslaughter.
When it comes to motivation, the evidence suggests that the offenses are usually related to the core phenotype of the particular autistic spectrum disorder (e.g., impaired social and communication skills) rather than to generic risk factors for crime, he said.
In fact, the factor most commonly associated with criminal offending among people with autism or Asperger's syndrome is the pursuit of circumscribed interests, such as theft of electronics for the purpose of disassembling them.
Some individuals offend because they are jealous of nonautistic people, or are angry or frustrated. Often, he noted, these are "people who feel hard-done by society and by others, and are really conscious of their deficits and have gone on to do something to kind of make themselves feel better."
Other factors that have led to criminal behavior include a desire for and naivete about relationships; coercion by dominant others; and mental health comorbidities, such as bipolar disorder.
Individuals with autism or Asperger's syndrome who have committed criminal offenses tend to have better performance in terms of theory of mind than their Asperger's counterparts who have not offended, Dr. Woodbury-Smith observed (J. Forensic Psychiatry Psychol. 2005; 16:747-63). Not unexpectedly, Asperger's offenders have poorer recognition of fear in others than do their nonoffending counterparts.
This same combination of factors has been identified in psychopathic individuals. "This led us to think that maybe there [is] a group of people with Asperger's who had offended who probably had a double hit when they were younger, inasmuch as they had the risk factors for an autistic spectrum disorder but also the risk factors for later going on to develop psychopathy," he said.
Dr. Woodbury-Smith noted that Asperger's syndrome is increasingly being diagnosed in people who have committed violent crimes, but the diagnosis is tenuous at best. In fact, "this is extremely rare--most people with Asperger's syndrome aren't going to come into contact with the criminal justice system," he said, and violence is not part of the syndrome's definition.
Much of Dr. Woodbury-Smith's research has focused on criminal behavior among people with the syndrome--particularly the neuropsychological correlates of the offending behavior. He also has cowritten several articles about high-functioning autistic spectrum disorders and criminal behaviors.
Diagnosing Asperger's syndrome in adults who have committed crimes is often challenging, according to Madelon Baranoski, Ph.D., of the department of psychiatry at Yale University, New Haven, Conn.
"The psychological indicators of autistic spectrum have been minimally identified in the literature for adults," she noted. "Secondarily, our testing material does not capture the extent or the nature of the disorder. …