Associations between autism and notorious violent crimes are easy to find--they seem almost automatic. Here is one example, and another, and one more. There seems to be an entire book on this theme, though I haven't read it.
In the scientific literature, you can find powerful deficit models of autism at work in predictions that autistics should disproportionately be violent and prone to criminal behavior. For decades now, examples and claims (just a few here, here, here, here) fitting this prediction have been highlighted, while the few dissenting views (e.g. here and here) have had little effect.
Then there's political expedience. Unless we receive the usual lobbied-for interventions, autistics will disproportionately display criminal behavior and wind up in jail--or so it is claimed. A few examples from the usual autism politics here, here, here.
Kathrin Hippler and her colleagues deserve high praise for noticing how well-placed they were to investigate these kinds of popular claims. Their recent paper takes advantage of their access to information about the large group of individuals--177 of them--who are former patients from Hans Asperger's clinical practice in Vienna.
Most (93%) of these former patients are male. All were assumed to score at least in the normal range of intelligence as children, but for most there are no recorded IQ scores. They were born between 1938 and 1979, and on average were diagnosed at age eight (range 3-21 years). In 2010 their average age would be about 50. It is unlikely that most of this cohort would have undergone the usual lobbied-for autism interventions as children.
Hippler et al. obtained information from the Austrian Penal Register about all criminal convictions registered, as of 2002, in this cohort. They found 33 convictions for a total of 8 individuals, resulting in 23 "custodial sentences" ranging from 2-30 months and 11 fines.
They also checked whether, compared to the general population, their cohort had a higher rate of newly-registered convictions for the years 1998-2002. Here is what they found:
the average proportion of convictions found in our sample (1.30%) is very comparable to that in the general male population (1.25%)As to kinds of crimes:
By far the most common convictions in Asperger’s former patients were for property offences [...] Offences against life and physical integrity were rare.And while data for the general population were limited:
qualitative assessment of offence types in Asperger’s former patients suggests that they do not differ radically from those in the general publicBecause this point needs to be underlined, here is more from Hippler et al.'s discussion:
the findings from our study do not suggest an over-representation of certain offence types. In the case records spanning 22 years and 33 convictions, there were only three cases of bodily injury, one case of robbery and one case of violent and threatening behaviour.Again to their great credit, Hippler et al. also provide data broken down according to Asperger's system of diagnosis. The 177 former patients were divided into an AP group ("autistic psychopathology," N = 73) and an AF group ("features of autistic psychopathology," N = 104).
Some guesswork is involved, but the AP group would fall under current criteria either for Asperger syndrome or the specific diagnosis of autism. Hippler et al. conservatively estimate one-third would be specific-autistic, but it's not difficult to find researchers who would guess a higher proportion (here, for example).
While a minority of the AF group might meet Asperger syndrome criteria, according to Hippler et al., others might be PDD-NOS, or in the (nonautistic) broader autistic phenotype. The AFs are described as "former patients at the less extreme end of the spectrum" and were included by Hippler et al. because:
Asperger believed that ‘autistic psychopathy’ was a heritable condition blending into "normality", which is reflected in the case descriptions of these children in the sense that the core features were the same but symptoms were less severe or could be compensated for better.According to near-universal assumptions, it would be far better to be AF (less "severe" or "extreme") than AP. Transforming AP-types into AF-types is a major goal of the usual lobbied-for autism interventions. But Hippler et al. found that most of the registered criminal convictions in their cohort belonged not to the "more autistic" AP group but to the "less autistic or not autistic at all" AF group.
Indeed, of the 33 convictions found registered as of 2002, only three convictions of two individuals were found in the AP group. The remaining 30 belong to six individuals in the AF group, with two in this group contributing 22 convictions.
In the comparison with rates of newly-registered convictions in the general population, the AP rate was 0.6% while the AF rate was 1.7%. These figures are lower and higher, respectively, than for the general male population, while the AP rate is comparable to the general population, females included (0.7%).
Hippler et al. provide a competent overview of the relevant literature (including this recent finding), as well as a fair discussion of their study's limitations. Under the banner "Wider Implications," they write:
There is a public perception that individuals with mental health diagnoses in general, and Asperger’s syndrome in particular, present a threat to the general public. We contend that, based on the follow-up data from Asperger’s original cohort, as well as other studies, this perception is wrong.Even wider implications include the neglected question of how being regarded as just naturally violent and dangerous to others, as natural born criminals, has affected the outcomes of autistics.
Hippler, K., Viding, E., Klicpera, C., & Happé, F. (2009). Brief Report: No Increase in Criminal Convictions in Hans Asperger’s Original Cohort Journal of Autism and Developmental Disorders, 40 (6), 774-780 DOI: 10.1007/s10803-009-0917-y
Postscript: This post has been included in the 43rd edition of Scientia Pro Publica.