Adam Lanza or the Genes of a Mass-Murderer

13 January 2013 by Stephan Schleim, posted in everyday life, neurolaw, neurophilosophy

Scientists will analyze the genome of the young man who recently killed almost thirty people in a mass shooting in the USA. Biology has been used frequently to understand criminality in the course of history, but with little success. It is unlikely that the genetic analysis will contribute to understanding the terrible crime. By contrast, it carries the risk of stigmatizing people with similar biological features and of overlooking psychological and sociological explanations.

While many people in the United States and the rest of the world are still mourning about the mass shooting in Newtown, Connecticut, that first cost Adam Lanza’s mother her life, then twenty school children and six employees, and finally himself, politicians are debating consequences of this and other recent violent incidents. This stimulated many Americans who are expecting stricter legislation to buy weapons, now that they are still easily available. Thus, ironically and sadly, there are currently many more such devices that can be used for killing people available in their society.

I do not want to judge the long American constitutional tradition concerning the liberty to own weapons, certainly not from an outsider’s perspective, living in Germany and the Netherlands where weapons are much stricter related (and shootings much less common), but while politicians and lobbyists are debating the legal consequences, many people are still puzzled by these cruel events. They are still asking why-questions, and understandably so. They are asking for an explanation of that which actually may be inexplicable. Is it evil, disease, madness that expresses itself in such deeds? Just a few weeks ago, co-blogger Jalees Rehman (Armchair Psychiatry and Violence) commented on the prevalence of common-sense explanations in the media, even including an account by Lanza’s hair stylist. Now a medical professional offers his help, Nature reports in the editorial of its current issue.

Biology of “Dangerous” People

Connecticut’s state medical examiner asked for the analysis of Lanza’s genome, that will now be carried out by geneticists at the University of Connecticut in Farmington. It is not unusual that scientists or doctors are looking for biological explanations of criminal behavior. Some may have heard of the infamous attempts of the Italian criminologist Cesare Lombroso (1835-1909) to recognize people’s character traits, particularly “born criminals”, in various physiological features such as eyebrow or ear shape, head form, even walking patterns. This approach first inspired many researchers internationally, but was then given up because Lombroso’s observations and predictions could not be confirmed.

Another famous case is that of the unfortunate railroad worker Phineas Gage (1823-1860) who became victim of an uncontrolled detonation at work that shot a huge iron bar through his frontal brain. In recent times, particularly the neurologist Antonio Damasio and others who proposed new neural theories of emotion or criminal behavior popularized this case again, describing the pre-accident Gage as a commendable man, the post-accident person as a psychopath who does not care about social norms, a liar, a dangerous person.

The Recovery of “Dangerous” Brains

Thanks to the historical work of the psychologist and historian of science Malcom Macmillan (The Phineas Gage Information Page), we know that these accounts are not based on the actual historical reports. There is no evidence for any criminal behavior or that he was a dangerous person in some other respect. By contrast, he was still capable of caring relationships in his family context, according to his mother’s report, entertaining his nieces and nephews, and showed great fondness for pets and other animals, particularly dogs and horses. My analysis of more recent cases supports the idea that people with such severe brain damage can function socially even without receiving treatment, given that they live in a stable and structured environment (Brains in context in the neurolaw debate). Macmillan coined this the social recovery hypothesis.

No psychopath’s brain: In contrast to common depictions in popular books and academic textbooks, there is no evidence for antisocial or criminal behavior of Phineas Gage after his accident. Left: Depiction of his damaged skull by his doctor John Harlow (1868). Right: Excerpt from a recently discovered photograph of Phineas and his tamping iron (see here for a note on the source and copyright)

There are many more cases where people investigated the possibility that criminal behavior may be due to some biological abnormality. In the period of post-war terrorism by the Red Army Faction (1970-1998) in Germany, there was much debate whether Ulrike Meinhof’s (1934-1976) behavior was due to a suspected brain tumor that she underwent brain surgery for in 1962, aged 28. Apparently, this operation caused severe brain damage, as shown by a post-mortem autopsy after she committed suicide in the high-security prison Stuttgart-Stammheim that was deliberately reconstructed in the young Federal Republic to cope with the threat of left-wing terrorism (see this German journalistic account of Meinhof’s brain from 2002). The Nature editorial actually gives another example that I had not known of before, the scientific study of the brain of the “vampire of Düsseldorf”, the serial killer Peter Kürten who was executed in 1931. It did not provide an answer to why he had become a serial killer.

From “Dangerous” Brains to “Dangerous” Genes

So there have been many attempts to correlate criminality with biological features. In virtually every fashion that influenced the course of science, be it genetics, hormones, brains, someone suspected that this research performed on criminals might provide the key to understanding why some people do terrible deeds. In my opinion, all of these accounts failed. Of course, there are some interesting findings, for example the recently discovered environment x genotype interaction between a traumatic childhood and the gene related to the enzyme MAOA that influences some neurotransmitters in the brain (I already wrote about this in my German blog, for example, here, here, or here).

But “interesting” here means that this stimulates further scientific hypotheses. The statistical effects are usually way too small to be practically relevant in individual cases. We are talking about slightly increased risks of, for example, aggressive behavior when provoked, not about gene-determination. The paradigm of behavioral genetics failed. Genes are of course essential for our lives, but they are very remote from actual behavior. Furthermore, the new paradigm of epigenetics shows that their functioning is modulated by the environment and experiences that people make.

The Risk of Stigmatization

So even if someone finds some abnormality in Adam Lanza’s genome, this will not provide an explanation for why he carried out this mass shooting in the Sandy Hook Elementary School on December 14 2012. At best, the findings might show that he was statistically slightly more likely to engage in aggressive behavior. As the Nature editors note, the genome is investigated “not because it will be useful but because it can be analysed.” I hope that nobody will neglect the investigation of the family and social structure in which Lanza grew up. This will provide the key to understand why he has become the person who killed so many people eventually, if there is an explanation, I suspect. In recent reports, ADHD or Autism are frequently mentioned in the context of his crime, but this rather demonstrates our tendency to assign medical labels to things that we do not understand than that it establishes an explanatory relation between the label and the behavior.

By contrast, such discussions rather carry the risk of stigmatizing innocent people. Even if the genetic investigation will yield some abnormality, there will be many people carrying this variant who do not perform criminal deeds; and, in turn, many people who do not carry this variant do perform criminal deeds. It has been like this with every biological marker so far, be it hormones, brains, chromosomes, you name it. We already know that there is no direct link between biology and behavior. The environment is essential; and in most of the investigations that I know, like the MAOA example given above, the environment’s and experience’s effects are actually much more robust than that of the genotype.

Hopefully we will be able to understand why such mass shootings occur and how we can prevent them; but the solution will be found in the social structure and personal experience, I believe, rather than in the biology.

Further Reading
Editorial (2013). No easy answer. Nature 493: 133.
Schleim, S. (2012). Brains in context in the neurolaw debate: The examples of free will and “dangerous” brains. International Journal of Law and Psychiatry 35: 104-111.

Laboratory Photograph: (C) Dieter Schütz /

5 Responses to “Adam Lanza or the Genes of a Mass-Murderer”

  1. Martin Wloszczynski Reply | Permalink

    Simply the fact that this is being done is worrying - it bears the potential for something like a scientist's witch-hunt: using obscure claims (behavioural genetics) to justify judgment (why did this happen?) and possibly taking action on that (forced treatment).

    The why-question is inevitable - the people who are affected by this hope to get closure through understanding, others hope that knowledge will help prevent such horrible deeds. The why-question shows involvement, that one cares about what happens. It almost seems like a social norm to ask why - imagine someone saying "I don't want to know why this happened" - that would seem indifferent, a violation of what seems appropriate in this situation. And anyone who strives to answer this question - whether through psychoanalysis or behavioural genetics - satisfies the need for an answer. An answer that - no doubt - might be accepted by some and refused by others. However, any answer we come up with can only shed light on a small part of the whole on which some people will agree. So we need a lot of answers to understand something like this - one answer is never enough.

  2. Chrys Reply | Permalink

    Scientists identify new ‘social’ chromosome in the red fire ant.

    “We now understand that chromosomal variants determine social form in the fire ant and it’s possible that special chromosomes also determine fundamental traits such as behaviour in other species.”

    • Stephan Schleim Reply | Permalink

      Thanks, Chrys – have you also checked how much the genetic variation correlates with the behavioral variation, and how much the environmental variation correlates with the behavioral variation?

      • Chrys Reply | Permalink

        The press release was issued yesterday and I have no further information. Anyway, to have identified a certain pattern does by no means imply to have found a mechanism by which behavior is genetically determined and controlled.

        However, I'm pretty sure about what they have eventually in mind when speaking of "other species" ;-)

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