HELSINKI (AFP) - Finns may have a reputation for sometimes drunken and violent behaviour but a new scientific study suggests their impulsive and reckless actions may be caused by a genetic mutation.

"When these people drink alcohol, their partly latent predisposition to impulsiveness is more likely to come out," Roope Tikkanen, a researcher at the University of Helsinki who led the study, told AFP.

Published in the journal of Translational Psychiatry, the study showed that 2.2 per cent of the population, or about 100,000 Finns, carry the mutation which makes them particularly susceptible to impulsive drunken behaviour.

So far, this mutation has been proven to exist only in Finns and it may go a long way towards explaining why drunken killings are unusually common in Finland.

While alcohol plays a role in many crimes around the globe, the Finnish Ministry of Justice records reveal that as many as 80 per cent of homicides and 70 per cent of assaults are committed by people under the influence of alcohol.

Researchers originally discovered the genetic mutation in 2010, among violent, alcoholic criminals.

Tikkanen said researchers found a mutation in the serotonin 2B receptor gene, which is thought to be linked to impulsivity in people with mental health problems.

The study, which was conducted among 200 average Finns with no criminal background, proved with a certainty of 95 percent that more than 100,000 of Finland's 5.4 million population are carriers of the mutation.

"In practice, these people are more likely to get into fights, have impulsive sex, waste their money or drive drunk," Tikkanen said.

Tikkanen noted that Finland's historical and geographic isolation had led to a relatively homogenous gene pool, which permitted the researchers to identify the impact of such a genetic mutation in the Finnish population.

The results also indicated that people with the mutation were more impulsive by nature even when sober, and more likely to struggle with self-control or mood disorders.

While vodka is the drink of choice in Finland, on average Finns do not necessarily drink more than other Europeans.

In 2009, adult Finns consumed 12.27 litres of pure alcohol per person, slightly less than the EU average of 12.45 litres.

"Alcohol just doesn't suit everyone, but it's surprising that we would have it in our genes," Kai, 45, said at a shopping centre in Helsinki.

Researchers believe the mutation is hereditary and hope the discovery could lead to new medicines being developed to treat detrimental impulsiveness.