According to a new study, the mutation in the brain's serotonin receptors is three times more common among people who have committed violent crimes while under the influence of alcohol than it is in the general population.
Around 6,000 Finnish people took part in the study, including 228 people with a history of alcohol abuse and a record of violent crime. Of the latter, 17 were found to have the genetic mutation. Altogether, the mutation was found in 97 of the subjects.
Another 3,000 non-Finns were also studied. Only one was found to carry the mutation, but on the basis of surname, it is assumed that this person is in fact of ethnic Finnish descent.
Researchers have stressed that the mutation alone does not trigger impulsive violence. The combination of the mutation and alcohol may, however, explain around eight percent of cases of violent behaviour while under the influence, according to the research group from Helsinki University, Finland's National Institute for Health and Welfare and the American National Institute of Health.