Genes may play a role in problems previously attributed to bad life experiences, according to some recent research:
When the link between smoking and lung cancer was emerging, smoking apologists asked whether some unknown biological factor (call it X) might have two effects, causing people to smoke and causing them to develop cancer. In that case, although the higher rate of illness among smokers might seem to implicate smoking, in fact X would be the cause of both smoking and cancer. Smoking would be an innocent bystander.
That turned out to be hogwash, of course. But the premise isn’t crazy. Indeed, it has returned to center stage in studies of how life experiences increase a child’s risk for depression, behavior problems and other bad outcomes.
The approach is called genetically informed research. The idea is to not be fooled into believing that a certain experience leads to a certain outcome but to probe whether a genetic predisposition (the X factor in the smoking analogy) leads to the experience and the outcome.
Take the conventional wisdom that their parents’ divorce increases the risk that children will develop depression. “It turns out that the increased risk of depression in these children reflects a common genetic liability in the parents and kids,” says Brian D’Onofrio of Indiana University, Bloomington. Since depressed people have more trouble getting and staying married, this genetic risk of depression raises their risk of divorce, he finds in a study submitted for publication. Parents pass that risk of depression to kids through DNA, not failed marriage.
“The same genetic risk that makes the parents more likely to divorce also makes the kids more likely to develop depression,” he says.
Sharon Begley, Genes, Not Experience Explains Why The Lives Of Some Take Bad Turn, WSJ.com – Science Journal, June 16, 2006, p. B1 (emphasis added).
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