Man would be more violent without alcohol

Risk factors for violence

When children and adolescents grow up in unfavorable environmental conditions, they tend to behave aggressively and criminally as adults

City life, physical or sexual abuse, experiences of migration, cannabis use, or problematic alcohol use during adolescence all increase the risk of young people behaving violently as adults. This is the result of a study led by Hannelore Ehrenreich at the Max Planck Institute for Experimental Medicine in Göttingen. The results provide the first scientifically based evidence that extreme social conditions can even change a person's gene activity.

In an earlier study, the researchers found that genetically predisposed people can develop schizophrenia about ten years earlier if they grow up in high-risk conditions and experience childhood abuse, sexual abuse, or head injuries, for example. The new results now show that the same conditions contribute five times the likelihood of being jailed or admitted to a forensic ward as an adult for violent behavior.

For their work, the researchers analyzed six independent study populations. The data comes from 1,500 people with schizophrenia and 550 people from the general Spanish population. The researchers examined whether a person had lived in a large city before the age of 18, immigrated, been physically or sexually abused, or consumed cannabis or alcohol. The researchers evaluated whether people with accumulated risk factors for violent crimes such as sexual assault, manslaughter, assault or murder had been convicted or had ever been admitted to a forensic facility.

Greater likelihood of violence

In all groups, people who were exposed to at least one of these risk factors were slightly more likely to become aggressive as adults. With each additional risk factor, the likelihood of violence gradually increased, which was reflected in a regular staircase pattern in all six populations. All of the high-risk factors taken together increase the likelihood ten times that a person with three or more risk factors will become violent as an adult.

"Our data support the thesis that violent aggression can develop in people who are exposed to several environmental risk factors at the same time before adulthood," says Ehrenreich. “This happens independently of the illness. In all cohorts, the accumulation of environmental risk factors before adulthood is related to later violent acts. It is noticeable that the composition of the risk factors is interchangeable. "

Epigenetic changes in high-risk patients

In addition, the researchers epigenetically analyzed the blood cells of a subgroup of 142 people. Higher levels of histone deacetylase-1 (HDAC1) mRNA were found in the samples from 33 high-risk men. HDAC1 is a mediator of epigenetic processes and thus of changes that can be brought about by environmental factors. "This is a first indication of epigenetic changes in the high-risk patients," says Ehrenreich.

The results of the study can help identify people at risk in the future and improve preventive measures and treatment programs.