In the wake of Elliot Rodger’s rampage, researchers speak with Uncommon Journalism about the possible links between autism spectrum disorders and murderous behavior.
|Mass murderer Elliot Rodger was diagnosed with Asperger syndrome at a very young age. According to a new report, individuals with similar neurodevelopmental disorders may make up a considerable minority of the total mass killer population.|
With the recent Isla Vista, Calif. murders grabbing international headlines, a recently published report analyzes the possible influence of neurodevelopment disorders -- in particular, autism spectrum disorders (ASDs) -- as factors in mass killings.
In “Neurodevelopmental and Psychosocial Risk Factors in Serial Killers and Mass Murderers,” which was featured in the journal Aggression and Violent Behavior in April, researchers from Scotland and Sweden evaluated 165 studies, ultimately investigating 239 killers who, since 1985, had taken at least three lives.
“Our research was interested in exploring the presence of a neurodevelopmental disorders and psychosocial stressors in very violent offenders, namely, serial killers and mass murderers,” Dr. Clare S. Allely, of the University of Glasgow’s Institute of Health and Wellbeing, told Uncommon Journalism.
About 7 percent of the killers suspected of having ASDs were also suspected of having brain injuries, the report indicates, with about 14 percent of killers with suspected head injuries also displaying evidence of ASD symptoms.
“The rarity of cases means that these individuals are unlikely to be part of general population studies or even clinical studies, except those focused on very atypical populations such as inmates of special hospitals for violent and mentally disordered offenders,” the report reads.
While researchers said existing literature on mass killers was limited, they nonetheless believe a sizable minority of the murderers they studied were likely to have neurodevelopmental disorders.
“Despite these limitations, we are able to say that probably more than 10 percent of serial/mass killers have ASD and a similar proportion have had a head injury,” the study states. “Because accounts of systematic examination for these factors are relatively uncommon in reports on serial/mass killings, these figures are very likely to be an underestimate.”
Criminal Autistic Psychopathy?
While neither were ever clinically diagnosed with an ASD, researchers evaluated U.S. serial killers Jeffrey Dahmer and Richard Ramirez as case studies. Per the authors of the study, “overwhelming evidence” indicates that Dahmer -- charged in 1991 with the murder of 17 people -- was likely an individual with Asperger syndrome. The condition, researchers argued, may have made it more difficult for Dahmer to deal with other stressors in his life, including sexual frustrations and his mother's severe depression.
Numerous prenatal factors -- among them, his parents being exposed to high levels of radiation and his pregnant mother collapsing in a factory where she mixed toxic chemicals -- very well could have neurologically impacted Ramirez, the study states. Ramirez, who died of natural causes while awaiting execution last year, would gain infamy as Southern California's "Night Stalker," who claimed 13 lives during the mid-1980s. In addition to experiencing multiple severe head injuries in his youth -- including almost being killed by a falling dresser when he was two -- researchers said that additional literature on Ramirez contain “suggestive descriptions of ASD traits.”
Links between autism spectrum disorders and violent behavior have been drawn by analysts and researchers in the past. In 2010, Irish psychiatrist Michael Fitzgerald addressed the issue of "criminal autistic psychopathy" in his book "Young, Violent and Dangerous to Know."
“One can see that many features of Autistic Psychopathy are contained in many of the personality disorder diagnosis of DSM-IV and ICD10,” Fitzgerald wrote. “These would include a detachment from social relations, a restricted range of emotional expression, suspiciousness, problems with interpersonal relationships and self image, discomfort in close relationships, hypersensitivity to negative evaluation, disregard for violation of the rights of others, grandiosity and a lack of empathy.”
"It is the most critical area of overlap for school shootings and serial killers," Fitzgerald told Uncommon Journalism in an e-mail exchange. "It is an urgent area of research."
Allely said that Fitzgerald’s hypothetical diagnosis -- effectively, a small subcategory of Asperger syndrome -- could be useful in differentiating the criminally violent subgroup from the wider pool of individuals with ASD diagnoses.
“Crucially, we are not suggesting that individuals with ASD are more likely to be serial killers or commit serious crime,” she said, "rather, and consistent with Fitzgerald, we are suggesting that there may be a tiny subgroup of individuals with ASD who are more likely to be serious offenders.”
Nature Against Nurture
In general, Allely said those with ASDs tend to have problems with “theory of mind,” specifically, difficulties intuitively working out what others may be thinking.
|A photograph taken of Jeffrey Dahmer in 1977.|
Fifteen years later, he would be charged with
17 counts of murder. Since his death in 1994,
many analysts have suggested that he may
have had undiagnosed Asperger syndrome.
Disinhibited and impulsive behavior, she added, were common among those with severe brain trauma, particularly those who have experienced frontal lobe injuries. The combination of ASDs and brain injuries, alongside major psychosocial stressors, Allely said, could prove a lethal combination.
Fifty-five percent of the killers in the study with suspected ASDs or brain injuries were also suspected of experiencing major psychosocial stressors, such as childhood abuse, severe physical illness or the death of a family member. This led to researchers suggesting that a “complex interplay between neurodevelopment and environmental factors” could possibly result in an individual being “predisposed” for serial killing or mass murder.
"Trying to elucidate how these various factors interact and relate to each other is challenging, primarily because of a lack of empirical research investigating the developmental trajectories of serial killers and mass murderers," Allely said.
Psychosocial factors, she added, could prove extremely important variables, however. "For example," she said, "of the six individuals with a definite ASD diagnosis, all have previous psychosocial stress such as child abuse or severe bullying."
Among those in the population with definite head injuries, Allely said four out of five subjects had experienced severe psychosocial stressors, such as sexual abuse. That said, as roughly 45 percent of the ASD cases the researchers analyzed were without clear evidence of psychosocial stressors, she advises caution when discussing the overall impact of negative life experiences on the population.
“Compared to serial killers and mass murders without evidence of brain disorders or ASDs, we do not know and we do not want to speculate as to whether killers with likely ASDs or brain disorders are more or less likely to report severe psychosocial stressors,” she said. “[Yet] psychosocial stressors do seem to be to be worth further attention in order to understand what influences very violent behavior.”
A Dearth of Literature and Recommendations for Future Research
The authors of the study note that ongoing research in the field is extremely limited, with only scant resources currently available regarding mass killer data.
“The problems with the quality of literature are compounded by the differing reporting strategies across the world, and the fact that serial killing, in particular, may go unrecognized,” the report reads. “We can therefore make no accurate estimations regarding the prevalence of serial/mass killing, and it is challenging to see patterns across populations that allow us to draw conclusions regarding etiology.”
However, Allely said there is growing interest in the field of study.
"We have recently become involved with a team of serial murder experts who participate in the Multidisciplinary Collaborative on Sexual Crime and Violence," she said. "One product of the collaboration is the Serial Killer Database Project, a catalog of serial murderers who fit the FBI definition."
The Radford/Florida Gulf Cost University project, she said, is of great use to law enforcement and academic researchers alike. However, Allely believes more research is necessary in order to understand the underlying mechanisms of extreme violence, especially in regards to the development of preventative strategies.
“The gaps in our understanding of the actual mechanisms of development toward these most negative of outcomes are enormous, and it is difficult to imagine how conventional research techniques could fill these,” the report reads.
Interestingly, one of the possible approaches suggested by the authors of the study is an international collaborative research model, similar to those used by the World Health Organization (WHO) and the European Union (EU) to investigate rare and deadly diseases.
“Similar technology may be required to understand -- and hopefully prevent -- serial and mass killings,” the report reads. “We would recommend in the future, serial or mass killers who are apprehended should be thoroughly assessed using standardized tools for investigating neurodevelopment disorders including ASD and head injury."
Further recommendations from the authors include new protocols, both domestically and internationally, to better measure the possible interplay between neurodevelopmental disorders and homicidal activity.
“A key consideration is to set up an international research registry to record information which is essential to understanding the developmental life trajectories of violent offenders,” Allely said, “as this may be the only way that we will eventually be able to confidently determine the prevalence, etiological factors and developmental trajectories associated with mass and serial killing, as well as other violent crime.”
Concerns About Mislabeling Autistic Individuals
In the study, researchers acknowledge that media reports on violent crimes committed by individuals with ASDs could lead to those with autism experiencing undue, and possibly harmful, stereotyping. Furthermore, the authors of the study state that current media tends to exaggerate the number of autistic individuals who actually commit violent crimes.
“Although the percentage of individuals considered to have a neurodevelopmental disorder is higher than would be expected in the general population,” the authors said, “this is nowhere near as high as indicated in the media.”
Nor does Allely want her own research to pigeonhole those with autism spectrum disorders as dangerous.
“With this particular field of research, if the appropriate approach is not adopted, it can be considered highly sensitive and controversial,” Allely said. “Our research group are dedicated to conducting high quality research within the field of ASD."
Allely said her research group was "actively and vehemently" opposed to the stigmatization of any individuals with autism spectrum disorders.
"It is imperative to emphasize here that research in fact shows that individuals with ASD are no more likely than the general population to engage in violent crime," she concluded, "and in fact, may actually even be less likely."
Uncommon Journalism, 2014.