The Cause Of Violence

October 28, 2014


An extensive study of criminals in Finland has identified two particular genes strongly associated with violent crime.

It’s All Relative

The scientists working on the project said those with the genes were 13 times more likely to have a history of repeated violent behavior, and that 4-10% of violent crime in the whole country could be attributed to offenders with these particular genotypes in their bodies.

However, the researchers emphasized that this was not a green light to screen suspected criminals or a guarantee of violent behavior, because of the multitude of other factors at play.

Other gene combinations in the body are likely to have an influence as well as the upbringing and social situation of the people in question.

The study, which involved almost 900 participants, is being published in Molecular Psychiatry. Professor Jari Tiihonen of the Karolinska Institutet in Sweden, who led the work, said that the majority of people with both these genes never go on to commit a violent crime, but the chance is greater.

“Committing a severe, violent crime is extremely rare in the general population,” he explained in an interview with the BBC. “So even though the relative risk would be increased, the absolute risk is very low.”

There Is Always A Choice

The genes in question are the MAOA gene and a variant of cadherin 13 (CDH13). MAOA is responsible for controlling the levels of dopamine and serotonin in the brain, while CDH13 has previously been associated with substance abuse and ADHD.

Deficiencies in the enzyme that MAOA produces are exacerbated when alcohol or drugs are involved — and the majority of crimes in Finland are carried out under the influence of one or both.

The discovery will help in the treatment of violent offenders and crime prevention techniques, but Professor Tiihonen says it’s human choice rather than genetic makeup that determines whether or not someone becomes a criminal.

“There are many things which can contribute to a person’s mental capacity. The only thing that matters is the mental capacity of the individual to understand the consequences of what he or she is doing and whether or not the individual can control his or her own behavior.”