A “red mist” gene that could be responsible for ordinarily peaceful people becoming violent and aggressive while drunk has been identified by scientists.
The team of researchers have found a genetic mutation in the brain that may contribute to violently impulsive behaviour under the influence of alcohol.
Researchers sequenced the DNA of several impulsive volunteers and compared those with DNA from an equal number of non-impulsive people.
They found a single DNA change that blocks a gene known as HTR2B was predictive of highly impulsive behaviour.
The gene affects serotonin production and detection in the brain.
Serotonin is a neurotransmitter known to influence many behaviours, including impulsivity.
“We found the genetic variant alone was insufficient to cause people to act in such ways,” said Dr David Goldman at the National Institute on Alcohol Abuse and Alcoholism in Maryland.
“Carriers of the HTR2B variant who had committed impulsive crimes were male, and all had become violent only while drunk from alcohol, which itself leads to behavioural disinhibition.”
In collaboration with researchers in Finland and France, Dr Goldman and colleagues studied a sample of violent criminal offenders in Finland.
The hallmark of the violent crimes committed by individuals in the study sample was that they were spontaneous and purposeless.
They found the association with HTR2B gene and then conducted studies in mice and found that when the equivalent gene is knocked out or turned off, mice also become more impulsive.
“Impulsivity, or action without foresight, is a factor in many pathological behaviours including suicide, aggression, and addiction,” said Dr Goldman. “But it is also a trait that can be of value if a quick decision must be made or in situations where risk-taking is favoured.”