Genetics and Jared Loughner

Here is a bit from a post by Kevin Mitchell on his Wiring the Brain blog. This wasn't written with Loughner in mind, but it got me thinking. Loughner probably has schizophrenia. But he may have an issue with impulse control. What I like about the following is that it is written by a scientist to let the lay audience get a sense of the state of research. You start to appreciate the complexity of the issue and the sophistication of current research:

If some guy spilt your beer by accident, would you punch him in the face? If he was unapologetic, you might at least consider it – you might in fact feel a pretty strong urge to do it. What stops you? Or, if you’re the type who acts on those urges, what doesn’t stop you? New research has found a mutation in one gene that may contribute to these differences in temperament.

Self-control is the ability to inhibit an immediate course of action in the pursuit of a longer-term goal or to consciously override a base urge. Some people show far more inhibitory control than others. This trait is very stable – indeed, inhibitory control in children, which can be assessed using the famous “marshmallow test”, is predictive of their score on scales of impulsivity as adults. (The marshmallow test must go down as one of the cruellest experiments in psychology – it involves asking four-year olds not to eat a lovely yummy marshmallow for five minutes, after which they will be given another one to go with it if they have resisted. The videos of these poor kids as they struggle to resist this urge are priceless). Impulsivity is also partly heritable – that is, more closely related people are more similar in this trait.

This is generally true of all personality traits, suggesting they are influenced by genetic variation. However, the specific genes involved are almost entirely unknown. Indeed, a recent study that failed to find any such genes was interpreted by many (e.g., 1, 2) as evidence that either personality was not really genetic or that measures of personality traits were effectively meaningless. In fact, this was a gross misinterpretation of the results of this study.

Go read the original to get the rest of the posting as well as to access the embedded links.

... researchers from the National Institutes of Health and from Helsinki have done in a new study that led to the identification of a mutation in the Finnish population that apparently affects impulsivity.

And this...

The scientists found one mutation that had never been seen in any other population – in the gene HTR2B, which encodes a receptor for serotonin. The mutation completely abolishes the production of the protein, so that people who carry one copy of this mutant version of the gene have only half the normal amount of the receptor protein. The mutant version was found to be greatly over-represented (7.5% frequency) among a set of 228 violently impulsive subjects, compared to 295 controls from the general population (1.2%). Among family members of the violent offenders who carried the mutation there was also an increased rate of the psychiatric disorders listed above, specifically in those relatives who also inherited the mutation.

These findings therefore suggest that this mutation increases the risk of this kind of violent, impulsive behaviour. It must only be one factor, however, as most of the 1% in the Finnish population who carry it are not violent criminals. Being male and alcohol abuse are two other likely risk factors.

This got me to thinking about Loughner and the fact that he was known to use Salvia as well as other drugs. Loughner is an example of all the complicating factors: he probably had an existing mental condition (schizophrenia), this might have been the expression of a genetic flaw (see above), but he exacerbated the problems by his drug taking and by the family life (neighbors way he was not allowed to interact with other children). Humans are complex. A lot of things went into Loughner's behaviour. But ultimately the legal system needs to cut through all that and use the concept of "free will" to convict him of his crime. It does no good to try and excuse behaviour because of your genes, your personality, your psychological state, prior child abuse, or drug taking. If you go down that path nobody can be held responsible for anything. So our legal system focuses on free will and makes judgements based on presumed moral responsibility.

Courts will exonerate if you are legally insane. But apparently Arizona won't exonerate, it allows a "guilty, but insane" verdict which puts you into a mental institute until you are judged sane, at that point you are moved to a prison to finish out your punishment. I actually think this is better than "innocent by reason of insanity". From Wikipedia:

If the person has a mental illness and it is determined that the mental illness interfered with the person's ability to determine right from wrong, and other associated criteria a jurisdiction may have, and if the person is willing to plead guilty or is proven guilty in a court of law, some jurisdiction have an alternative option known as either a Guilty but Mentally Ill (GBMI) or a Guilty but Insane verdict. The GBMI verdict is available as an alternative to, rather than in lieu of, a "not guilty by reason of insanity" verdict.[5] Michigan (1975) was the first state to create a GBMI verdict.

Sadly Jared Louhner apparently has no interest in explaining his actions. He is using the legal shields (protection from self incrimination) to refuse to discuss and explain his actions. That is profoundly upsetting because, as humans, we like to understand our world, have it make sense. I suppose that over time the enigma of Jared Loughner will be unraveled. In the meantime that one person has left so much death and destruction in his wake. He is like a parasite. A society can struggle on so long as the parasite load is modest, but once parasite proliferate, the healthy population collapses. The US can withstand the occasional Jared Loughner, but above a certain level and the society collapses as violence and mistrust spreads.

The obvious solution, from a Canadian perspective, is to adjust the balance between individual rights and group rights. The individual has a right to freedom, but a group has a right to security. Removing guns from the population would move the balance more toward group security. But fanatics in the US, the NRA in particular, refuse to consider that. They have construed the Bill of Rights to provide an unrestricted right to citizens to arm themselves. But in fact the Constitution was addressing the rights of states to raise militias to protect themselves. This fundamental confusion between individual rights and group rights is behind all the suffering which a case like Loughner's assassination brings to the US.