A genetic mutation may make it difficult for you to hold your liquor and may make you susceptible to reckless behavior when drunk, say University of Helsinki researchers. They estimate more than 100,000 Finns, or 2.2 percent of the population, carry this mutation.

“Carriers demonstrated aggressive out-bursts, got into fights, and behaved in an impulsive manner under the influence of alcohol,” wrote the research team led by Dr. Roope Tikkanen, a psychiatrist. While some might call this an “average Saturday night,” the new preliminary research points to a plausible genetic explanation for out of control behavior.

Underlying Genetics

The serotonin 2B receptor binds to the neurotransmitter popularly believed to contribute to feelings of peace and happiness. A 2010 study, which genotyped its participants (228 violent offenders, 352 of their relatives, and 295 healthy controls), identified some who carried a mutation in the serotonin 2B receptor. Further examination revealed the mutation to be widely expressed in the brain with high densities in the frontal lobe (executive function), cerebellum (movement coordination), and the occipital lobe (vision). The 2010 study also linked the serotonin 2B receptor to impulsivity, a feature of some forms of mental illness.

For the current study, Tikkanen and his colleagues continued where this earlier research left off; they began by enlisting the help of participants (excluding the violent offenders) in the 2010 study. First, the research team divided the participants into two separate groups, both similar in age and educational scores. The first group consisted of carriers of the mutation and included relatives of the violent offenders as well as healthy controls. The second group included only healthy controls without the mutation. After experienced psychiatrists conducted interviews and examined the participants, the research team analyzed the data.

One of their main findings was that the mutation predicted alcohol-related risk-behaviors, the researchers concluded. Along with higher levels of aggression, the carriers of the mutation had been arrested for driving while under the influence of alcohol more often than the others.

Importantly, the “carriers were not alcoholics per se, as measured by average alcohol consumption, and were not diagnosed as alcoholics,” the researchers wrote; however, “they had a tendency to lose behavioral control while under the influence of alcohol.”

Even when sober, participants with the mutation were more impulsive by nature and more likely to struggle with mood disorders, these preliminary results indicated. Noting the study’s limitations, the researchers say further investigation of this mutation is necessary. Still, preventive measures for carriers would include drinking less or not at all, while increasing control over emotions and impulsive behavior through psychotherapy.

Source: Tikkanen R, Tiihonen J, Rautiainen M-R, et al. Impulsive alcohol-related risk-behavior and emotional dysregulation among individuals with a serotonin 2B receptor stop codon. Translational Psychiatry. 2015.