Researchers led by a group of scientists at the National Institutes of Health have discovered a genetic variant that may be a significantly contributing factor in what causes some people to be unable to control their violent impulses. This finding could have wide implications into the study of what biological factors influence impulsive behavior in humans. Perhaps impulsive behavior runs in your family tree?
The researchers took a look at a sample of people who were violent criminal offenders from Finland. This group was intentionally selected for a few specific reasons. Finland has a unique population history. Most Finns are descended from a small group of original settlers. This means that there would be less variables in the genetics in this sample than there would be from a sample of violent offenders from another country, that had a much more diverse genetic history. The less variables the researchers had to deal with, the easier it would be for them to find a gene that influenced impulsive behavior.
The other reason why this group was selected is because everyone in the group committed a violent crime that was spontaneous, and without purpose. The genes collected from the sample were compared with the genes of an equal number of Finnish non-impulsive people.
There is a gene called HTR2B that encodes a certain kind of serotonin receptor in the brain. The violent offenders all had a variant that blocked the HTR2B gene from doing what it was supposed to do. Another thing that the researchers found was that all of the violent offenders were male, and all of them were intoxicated from alcohol when they became violent. It may be no surprise to learn that alcohol can have an influence that causes some people to be impulsive. It seemed that the presence of the genetic variant wasn’t enough, on it’s own, to make a person behave impulsively. Alcohol was a necessary component to cause a person to display violent, impulsive, behavior. The findings of this study could lead to finding better strategies for diagnosing and treating people who have severe problems with impulsive behavior.
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