Is bad behavior determined by a child’s genes? A new study has found that a particular gene has some influence on whether or not adolescents show alarming behaviors—but only if their parents aren’t keeping tabs on them. While this gene, which has been linked to alcoholism, has only a small effect on the risk of behavioral problems by itself, psychological scientists view this finding as an opportunity to understand how genetic risk combines with environmental factors to contribute to psychological outcomes and disorders.
“There are a lot of big gene-finding projects going on for a lot of psychiatric conditions,” says Danielle Dick of Virginia Commonwealth University, lead author of the new study. Dick and other scientists from nine institutions in the U.S. and the Netherlands sought to find potential genetic links to externalizing, or disruptive, behavior in children. The study, published in Psychological Science, a journal of the Association for Psychological Science, focused on a gene called CHRM2, which was originally associated with alcoholism in the Collaborative Study on the Genetics of Alcoholism.
Psychological scientists have been studying disruptive behavior in children for years. Recently, studies on twins have found that parental monitoring—a factor related to how well a parent knows what’s going on in their child’s life—is a key moderator of the importance of genetic predispositions on substance use. In addition to sparking familiar campaigns to get parents to ask their kids what they’re doing, where they’re going, and who they’re hanging out with, this finding led Dick and her colleagues to explore whether parental monitoring could change the effects of CHRM2 in children with behavior problems.
For the study, the researchers collected data from about 450 volunteers who had been followed since they were kindergarteners in the late 1980s, as part of a long-term child development study. The researchers acquired DNA samples as well as reports about the kids’ behavior over time. “Essentially, we were looking at particular genetic variants that are correlated with behavior problems and asking whether environmental conditions changed the likelihood that kids carrying high risk genotypes would display problem behaviors,” Dick says.
By itself, the CHRM2 gene didn’t determine whether or not a child had behavior problems in adolescence. But when parents were less aware of their children’s activities, having a particular variant of the CHRM2 gene did make kids more likely to display problematic behavior as adolescents—not only substance use, but bad behavior in general.
“This is not a gene for anything. It’s a gene that increases or decreases your risk a tiny bit, depending on environmental conditions” Dick says. Many genes—probably hundreds—contribute to the risk for behavior problems. “The goal of this research is to find a bunch of genes that, when put together, tell us something meaningful about someone’s risk for a particular outcome, and to understand how environmental conditions may change that risk” she says.
Studies like this one have only become possible in the last few years, and they’re beginning to expand how psychological scientists think about psychiatric disorders. Over time, with the results of many such studies, it may begin to be possible to examine one person’s genes and get a sense of their risk for psychiatric problems. Dick says, “The challenge will be to understand the pathways by which genetic risk unfolds, and to understand what environments modify that risk, in order to develop better prevention and intervention efforts.”