NIH Logo Violently impulsive behavior seems to be the result of a genetic variant in the brain receptor molecule. Experts from the National Institutes of Health have apparently found a genetic variant of a brain receptor molecule that is involved in violently impulsive behavior witnessed among people under the influence of alcohol. Impulsivity or action without foresight appears as a factor in many pathological behaviors including suicide, aggression, and addiction.

While conducting the research, scientists examined a sample of violent criminal offenders in Finland. Majority of the crimes committed by individuals in the study sample were spontaneous and purposeless. DNA of the impulsive subjects was sequenced and compared to sequences with DNA from an equal number of non-impulsive Finnish control subjects. As a result, an alteration in a single DNA blocking the HTR2B gene apparently predicted highly impulsive behavior. It is presumed that HTR2B encodes one type of serotonin receptor in the brain.

David Goldman, M.D., chief of the Laboratory of Neurogenetics at the NIH’s National Institute on Alcohol Abuse and Alcoholism (NIAAA), senior investigator, shared, “We conducted this study in Finland because of its unique population history and medical genetics. Modern Finns are descended from a relatively small number of original settlers, which has reduced the genetic complexity of diseases in that country. Studying the genetics of violent criminal offenders within Finland increased our chances of finding genes that influence impulsive behavior.”

While carriers of the HTR2B variant who had committed impulsive crimes were male, all had become violent only while drunk from alcohol, which itself is known to trigger behavioral disinhibition. Experiments conducted on mice found that when the equivalent HTR2B gene is knocked out or turned off, mice also become more impulsive. The research findings can probably assist in providing a detailed insight into certain aspects of impulsivity and also lead to strategies for diagnosing as well as treating some clinically important manifestations of impulsive behavior.

The research was published in the December 23 issue of Nature.