Violent behavior in autism spectrum disorder: Is it a fact, or fiction? A spasm of school violence brought a putative link between autism spectrum disorder (ASD) and violent crime into public consciousness—even though no specific association exists between autism and violent crime. When a person with ASD commits a violent act, a key step in your workup is to identify or exclude a comorbid psychiatric disorder that might, in fact, explain the offending behavior. Mohammad Ghaziuddin, MD 1 Professor of Psychiatry hen Kanner first described autism, the disorder was be- Section of Child Psychiatry lieved to be an uncommon condition, occurring in 4 of ev- University of Michigan ery 10,000 children. Over the past few years, however, the Ann Arbor, Michigan W rate of autism has increased substantially. Autism is now regarded as Disclosure a Dr. Ghaziuddin reports no financial relationship with a childhood-onset spectrum disorder characterized by persistent defi- any company whose products are mentioned in this cits in social communication, with a restricted pattern of interests and article or with manufacturers of competing products. activities, occurring in approximately 1% of children.3 In DSM-IV-TR, Asperger’s disorder (AD), first described as “autistic psychopathy,”4 is categorized as a subtype of ASD in which the pa- tient, without a history of language delay or mental retardation, has autistic social deficits that do not meet full criteria for autism. DSM-5 eliminated AD as an independent category, including it in- stead as part of ASD.5 The label “high-functioning autism” is sometimes used to refer to persons with autism who have normal intelligence (usually defined as full-scale IQ >70), whereas those who have severe intellectual and communication disability are referred to as “low-func- tioning.” I use “high-functioning autism” and “Asperger’s disorder” interchangeably. Violent crime and ASD/AD Reports in the past 2 decades have described violent behavior in per- sons with ASD/AD. Because of the sensational and unusual nature aGiven the term pervasive developmental disorders (PDD) in the DSM-IV-TR, the spectrum includes autistic disorder, Asperger’s disorder, and pervasive developmental disorder not otherwise specified.2 ROY SCOTT/ILLUSTRATION SOURCE Current Psychiatry Vol. 12, No. 10 23 Table in the assessment of childhood psychi- atric disorders, ASD/AD might be mis- What are distinctive features diagnosed as schizophrenia or another of offending behavior in people psychotic disorder. What clues help iden- a who have ASD? tify underlying ASD/AD when a patient is They make no attempt to conceal offending referred to you for psychiatric evaluation behavior after allegedly committing a violent crime? Violence Their behavior is often based on special in ASD interests Clue #1. He makes no attempt to deny or They are naïve and difficult to understand conceal the act. The behavior appears to be Their offending behavior results from part of ritualistic behavior or excessive in- misreading social cues terest (Table). Their offending behavior is often the result Often, the alleged crime occurs when of other factors, such as depression and psychosis the patient’s excessive interests “get out aNot all features seen in all affected people of control,” perhaps because of an exter- nal event. For example, a teenager with Clinical Point AD who is fixated on video games might Pay attention to a stumble upon pornographic web sites and of these criminal incidents, there is a per- begin making obscene telephone calls. history of difficulty ception by the public that persons with Particular attention should be paid to a relating to peers these disorders, especially those with history of rigid, restricted interests begin- at an early age, AD, are predisposed to violent behavior. ning in early childhood. combined with (Incidents allegedly committed by persons These restricted interests change over with ASD include the 2007 Virginia Tech time and correlate with intelligence level: evidence of rigid, campus shooting and the 2012 Newtown, The higher the level of intelligence, the restricted fixations Connecticut, school massacre.6) more sophisticated the level of fixation. and interests Yet neither the original descriptions Examples of fixations include computers, by Kanner (of autism) and Asperger, nor technology, and scientific experiments and follow-up studies based on the initial sam- pursuits. Repeated acts of arson have been ples studied, showed an increased preva- reported to be part of an autistic person’s lence of violent crime among persons with fixation with starting fires.8 ASD/AD.7 In this article, I examine the evidence Clue #2. He appears to lack sound and pru- behind the claim that people who have dent judgment despite normal intelligence. ASD/AD are predisposed to criminal vio- Although most patients with ASD score lence. At the conclusion, you should, as a in the intellectually disabled or mentally physician without special training in au- retarded range, at least one-third have an tism, have a better understanding of when IQ in the normal range.9 Examine school to suspect ASD/AD in an adult who is in- records and reports from other agencies volved in criminal behavior. when evaluating a patient. Pay attention to a history of difficulty relating to peers at an early age, combined with evidence of When should you suspect rigid, restricted fixations and interests. ASD/AD in an adult? It is important to obtain a reliable histo- Although autism is a childhood-onset dis- ry going back to early childhood, and not Discuss this article at order, its symptoms persist across the life rely just on the patient’s mental status; pre- www.facebook.com/ span. If the diagnosis is missed in childhood, senting symptoms might mask underlying CurrentPsychiatry which is likely to happen if the person has traits of ASD, especially in higher-func- normal intelligence and relatively good ver- tioning adults. (I once cared for a young bal skills, he (she) might come to medical at- man with ASD who had been fired a few tention for the first time as an adult. days after landing his first job selling used Because most psychiatrists who treat cars because he was “sexually harassing” Current Psychiatry 24 October 2013 adults do not receive adequate training his colleagues. When questioned, he said that he was only trying to be “friendly” Program, violent crime comprises four and “practicing his social skills.”) offenses: murder and non-negligent man- slaughter, forcible rape, robbery, and ag- Clue #3. He has been given a diagnosis of gravated assault.11 schizophrenia without a clear history of Earlier descriptions of ASD/AD did not hallucinations or delusions. mention criminal violence as an important Differentiating chronic schizophrenia and feature of these disorders. However, re- autism in adults is not always easy, especial- ports began to emerge about two decades ly in those who have an intellectual disabil- ago suggesting that people who have ity. In patients whose cognitive and verbal ASD—particularly AD—are prone to vio- skills are relatively well preserved (such as lent crime. Some of the patients described AD), the presence of intense, focused inter- in Wing’s original series12 of AD showed ests, a pedantic manner of speaking, and violent tendencies, ranging from sudden abnormalities of nonverbal communication outbursts of violence to injury to others be- can help clarify the diagnosis. In particular, cause of fixation on hobbies such as chem- a recorded history of “childhood schizo- istry experimentation. phrenia” or “obsessive-compulsive behav- Reports such as these were based on iso- Clinical Point ior” going back to preschool years should lated case reports or select samples, such A recorded history alert you to possible ASD. as residents of maximum-security hospi- tals. Scragg and Shah, for example, sur- of ‘childhood Scales and screens. Apart from obtaining veyed the male population of Broadmoor schizophrenia’ or an accurate developmental history from a Hospital, a high-security facility in the ‘obsessive-compulsive variety of sources, you can use rating scales United Kingdom, and found that the prev- behavior’ going back and screening instruments, such as the Social alence of AD was higher than expected in to preschool years and Communication Questionnaire10—al- the general population.13 though their utility is limited in adults. It is Recent reports have not been able to should alert you to important not to risk overdiagnosis on the confirm that violent crime is increased in possible ASD basis of these instruments alone: The gold persons with ASD, however: standard of diagnosis remains clinical. The • In a clinical sample of 313 Danish critical point is that the combination of core adults with ASD (age 25 to 59) drawn symptoms of social communication deficits from the Danish Register of Criminality, and restricted interests is more important Mouridsen and colleagues found that per- than the presence of a single symptom. A sons with ASD had a lower rate of criminal touch of oddity does not mean that one has conviction than matched controls (9%, com- ASD/AD. pared with 18%).14 • In a small community study, Woodbury-Smith and colleagues examined Is the prevalence of violent crime the prevalence rates and types of offending increased in ASD/AD? behavior in persons with ASD. Based on of- It is important to distinguish violent crime ficial records, only two (18%) had a history from aggressive behavior. The latter, which of criminal conviction.15 can be verbal or nonverbal, is not always intentional or malevolent. In some persons who have an intellectual disability, a desire The role of psychiatric to communicate might lead to inappropri- comorbidity ate touching or pushing. This distinction Psychiatric disorders are common in per- is particularly relevant to psychiatrists be- sons who have ASD. In one study, 70% cause many people who have ASD have an of a sample of 114 children with ASD intellectual disability.