The lack of serotonin pushes people to violence
Last reviewed: 16.10.2021
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Irritable people would be much calmer if they had more neurotransmitter serotonin.
The researchers planted 19 healthy volunteers on a diet that reduced serotonin levels, and then scanned their brains. It turned out that as a result, the connection between the amygdala-shaped body that processes fear and the prefrontal cortex that constrains it has been broken. This split in the brain can provoke a disproportionately violent response to a relatively mild threat.
The effect was found by showing to volunteers who were depleted of serotonin, photographs of sad, angry and neutral persons during a functional MRI of the brain. Participants were also asked to determine who is pictured in the picture - a man or a woman. It was a distraction: in fact, scientists were interested in the brain's reaction to the threat emanating from an angry person.
The most serious disruption of the connection between the amygdala and the prefrontal cortex was recorded in people who, at the time of questioning, confessed to a propensity for violence. "As if the intermediate voice of reason was lost," says the team leader Luca Passamonti of the University of Catanzaro (Italy).