The Externalizing Consortium, an international research group co-founded by La Follette School Professor Philipp Koellinger, has identified 579 locations in the human genome associated with behaviors and disorders related to self-regulation, including addiction and child behavior problems.
The study produced genetic risk scores—an estimate that reflects a person’s overall genetic propensity—which are associated with a range of behavioral, medical, and social outcomes, including alcohol consumption, opioid use, suicide, criminal convictions, unemployment, and attention deficit hyperactivity disorder (ADHD). Published in Nature Neuroscience, it drew on data from 1.5 million people of European descent and is one of the largest genetic studies to date.
The behaviors and disorders discussed in the study are known as externalizing behaviors. Related to an inability to control impulses, they can have profound consequences for individuals, their families, and their communities.
As Koellinger explains, the study illustrates that “genes pre-wire our brains, which can increase or decrease our tendency to think or act in certain ways. The genes we identified in the study are linked with self-control or impulsivity and can confer risks for a variety of outcomes spanning the entire lifespan–from behavioral problems during childhood, personality characteristics such as risk-taking and extraversion, socioeconomic status and substance use during adulthood, all the way to a broad range of mental and physical diseases, including higher risks for HIV infections and suicide attempts.”
Having a higher genetic risk for externalizing isn’t necessarily a bad thing, Koellinger notes. “For example, entrepreneurs are often higher on risk-taking, and many highly creative and productive people score high on extraversion and openness—all aspects of the externalizing spectrum that we studied here,” Koellinger said. “Our genes are not our destiny. We all have unique genetic codes, and we’re all at risk for something; but understanding one’s genetic predisposition can be empowering—it can help us understand our strengths and weaknesses, and act accordingly.”
Studies of the human genome have typically looked at just one trait associated with one location on the human genome. But using new data analysis techniques allowed the researchers to widen their focus to multiple traits. This, in turn, allowed them to identify a large number of locations on the human genome associated with a wide range of behaviors and disorders.
The study was conducted by a consortium of 26 researchers at 17 institutions in the United States and the Netherlands and was led by Koellinger, Danielle Dick (Virginia Commonwealth University), Kathryn Paige Harden, (University of Texas at Austin) and Abraham Palmer, (University of California, San Diego). The authors have developed a FAQ with additional information about the study and its findings.
Support for the study was provided by the National Institute on Alcohol Abuse and Alcoholism, the National Institute of Drug Abuse, an ERC Consolidator Grant to Philipp Koellinger, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Jacobs Foundation, the Brain and Behavior Foundation, and the California Tobacco-Related Disease Research Program.