Genetic Variant Can Lead to Severe Alcohol-related Impulse Behaviors


Alcohol can cause personality changes, but in each individual, the effect is different. Researchers from the NIH’s National Institute on Alcohol Abuse and Alcoholism (NIAAA) have found that a genetic variation may be the cause of the violently impulsive behaviors that some people exhibit.

Alcohol Blocks Serotonin Receptor Site Leading to Impulsivity

Alcohol can affect several different parts of the brain, but in general, the substance contracts brain tissue and depresses the central nervous system. It can also destroy brain cells, interfering with communication between the nerves. When the cerebral cortex is affected, the effects include depressed inhibition and poor judgment.

Dr. David Goldman, senior author of the study and chief of the Laboratory of Neurogenetics at the NIAAA, studied a sample of male violent criminal offenders in Finland. The hallmark of their crimes was that they were spontaneous and purposeless and occurred while the offender was drunk from alcohol.

Read: Alcohol Abuse and Addiction Affect Suicide Rates


The researchers sequenced the DNA of the subjects and compared it to the DNA of an equal number of control subjects. They found that a DNA change that blocks a gene known as HTR2B was predictive of highly impulsive behavior. HTR2B regulates serotonin release, a neurotransmitter which influences behaviors such as impulsivity.

The genetic variant alone, however, was insufficient to cause the people to act in such violent ways. The researchers then turned their study to mice and found that when their equivalent gene was “knocked out or turned off”, the mice became more impulsive. Studies with the interaction between alcohol and the HTR2B gene are ongoing.

Read: Alcohol More Harmful than Heroin, Cocaine, or Ecstasy

“Impulsivity, or action without foresight, is a factor in many pathological behaviors including suicide, aggression, and addiction,” says Dr. Goldman. It is also a complex trait with many possible genetic and environmental causes.

The findings could lead to a better understanding of impulsivity and could also be important in the treatment of addiction behaviors.