Researchers find genetic clues to impulsive behaviour

A global research team has uncovered a genetic mutation which appears to be responsible for certain types of impulsive behaviour.

The study, led by the National Institutes of Health screened 96 convicted violent criminals in Finland for 14 candidate genes, comparing them to a control group of the same size. The criminals were selected on the basis of having committed seemingly random, pointless crimes, the overwhelming majority of which occurred under the influence of alcohol.

The researchers found that a single DNA change that blocks a gene known as HTR2B was predictive of highly impulsive behaviour. HTR2B encodes one type of serotonin receptor in the brain. Serotonin is a neurotransmitter which is linked to impulsive behaviours as well as mental illnesses such as depression. Suicide victims typically show particularly low levels of serotonin in their spinal fluid.

Finland was chosen because of its unique population history and medical genetics. The country’s population is believed to have stemmed from just two major immigration waves.

The genetic variation identified by the study is reasonably common in Finland but is yet to be identified outside of the country.

The researchers said that the fact of a genetic variant being linked to impulsive behaviour under specific conditions in an isolated human population, combined with the findings related to the role played by alcohol could eventually lead to important discoveries regarding the treatment of certain behaviour disorders.

The study has been published in the December 23 issue of Nature.