In the study, antisocial behaviour is defined as a collective term for transgressing rules by doing such things as stealing, acts of vandalism, being aggressive and exhibiting other destructive behaviour. The researchers discovered that individual genes have a very small effect on antisocial behaviour. Nonetheless, the overall effect of all genes together does explain some part of the variation observed. The results of this research, led by Jorim Tielbeek of VU Amsterdam, were recently published in the leading scientific journal Molecular Psychiatry.
Link to brain development
Jorim Tielbeek explains: “Even though the effect is small, we did find a link with the so-called FOXP2 gene. That’s a gene involved in multiple aspects of brain development.” The study examined independent random samples from the United States, Canada and the United Kingdom of subjects who voluntarily donated their DNA and filled in questionnaires about antisocial behaviour. Thanks to its international dimension, this study shows that the genetic risk of antisocial behaviour also appears in random samples in other parts of the world and is associated in each place with different antisocial outcomes, such as a criminal conviction or diagnosis of a behavioural disorder.
Link to health
In addition, the study reveals that the same genes that influence antisocial behaviour are linked in a negative way to mental health (depression, insomnia) and physical health (being overweight, smoking). Follow-up studies of the high-risk genes identified will enable us to better understand how our brains work. Ultimately, this research will contribute to better treatments for antisocial behaviour.
Future research
The researchers admit that one limitation of the study is that they only looked at genetic variants that occur reasonably often (more often than 1%) in individuals of European heritage. It may well be that other genes play a more important role in antisocial behaviour among individuals of other ethnic groups. Because of the Eurocentric bias of most scientific research, these groups are often insufficiently studied. Tielbeek: “A Eurocentric vision leads to less data being collected from non-European subjects, which means the progress science is making only reaches a small portion of the world population.” In future studies, therefore, Tielbeek and his colleagues want to explicitly focus on a diversified group of subjects, while also searching for genetic variants that are more rare. Not only that, the current results show that the bigger the study, the bigger the chance that new high-risk genes will be identified. That means even greater trials (with millions of subjects) will be needed in order to find all the high-risk genes linked to antisocial behaviour.
Environmental factors
The study is an important step towards understanding how genetics is involved in antisocial behaviour. Tielbeek underscores the fact that these results only tell the story from one angle. “A person’s environment is just as important. Genetics can only explain part of what’s going on; ultimately, it’s the combination of genetic and environmental factors that leads to increased risk. Just having high-risk genes therefore does not determine that someone will develop antisocial behaviour. Future research will be needed to provide deeper insight into how high-risk genes and environmental factors interact in contributing to antisocial development,” Tielbeek maintains.