Tuesday, September 30, 2008

It really is in your nature

Rarely will you see a scientist get more riled up than when thrust into a debate of Nature versus Nurture. While the cliche term covers a lot of different aspects of science, the basic debate centers around exactly how much of who we are lies in our genes. A new study in the Journal of Biopsychiatry gives the edge to Dawkins & Co. They found that boys with behavioral problems actually have different levels of the stress hormone cortisol than normal ones - so they can blame their genes, not their parent's upbringing, for their out-of-control antics.

Cortisol, a stress hormone, is generally released when a person gets upset or anxious. The daily patterns of cortisol production were similar in delinquent and control volunteers. When control subjects played a stressful game, however, their cortisol levels rose 48%, while the levels of cortisol in the boys with conduct disorder dropped by 30%. The researchers, based at the University of Cambridge, suggest that this huge difference may be because the delinquent youths are so used to provocative and stressful encounters that they no longer respond by producing the "restraining" hormone cortisol. "They are behaving as though there's no stress at all," says lead researcher Graeme Fairchild.

In psychology, there is an assumed difference between children with early-onset problems, starting around age five, and those who start acting out at later ages. The ones that act out young are thought to have a 'biological problem,' whereas the teen troublemakers are responding to peer pressure or familial upbringing. But in this study, it didn't matter when the onset of behavior occurred. They found no difference between early and late blooming disorders: both group's cortisol levels fell the same way – a biological rather than peer-led response, suggesting that there isn't as much difference in the two groups as previously thought.

"It could be that the same latent trait exists in both groups," says Fairchild. These findings may lead to the discovery of biological markers in infants that identify those most likely to develop conduct disorders at any age, allowing parents to be better equipped to deal with their behavior later on before it degenerates into lying, stealing, violence, and general apathy for well being of others. Or the research could lead to new treatments to bring cortisol levels closer to normal, curbing bad behavior chemically.

Either way, it seems that Nature has scored a point in a field, psychiatry, where Nurture has tended to dominate- at least until the next study is published.

** UPDATE: Study Finds Gene May Indicate Likelihood To End Up In Wrong Crowd **
New study out of FSU correlates a specific gene mutation with hanging out in 'bad' crowds. The gist of the research, published in the September issue of the Journal of Genetic Psychology, is that boys with high-risk families who also have a specific allele (called the '10-repeat allele' of the dopamine transporter gene (DAT1)) are more likely to hang out with delinquent peers than those in high-risk families who do not. Interestingly, those without the gene and all in low-risk families do not correlate with poor choice of friends, showing that the environment also plays a role.

Kevin Beaver, the lead investigator, explains, "As a result, we now have genuine empirical evidence that the social and family environment in an adolescent's life can either exacerbate or blunt genetic effects...Perhaps the 10-repeat allele is triggered by constant stress or the general lack of support, whereas in low-risk households, the variation might remain inactive...Or it's possible that the 10-repeat allele increases an adolescent boy's attraction to delinquent peers regardless of family type, but parents from low-risk families are simply better able to monitor and control such genetic tendencies."

Soon enough there just may be a genetic test for 'risk of adverse behavior as a teenager.' Crazy, huh?