Author: Falishia Sloan
Institution: Eastern Virginia Medical School
Date: November 2007
In research published online in a November edition of Nature, researchers from the University of Groningen in the Netherlands have found that a deficiency in serotonin is associated with abnormally violent, aggressive behavior.
Sietse de Boer, PhD, who performed the research with his colleagues, stated, "Serotonin deficiency appears to be related to pathological, violent forms of aggressiveness, but not to the normal aggressive behavior that animals and humans use to adapt to everyday survival."
Serotonin, also known as 5-hydroxytryptamine, is a hormone responsible for the transmission of signals between neurons (nerve cells) as well as a chemical messenger that causes blood vessels to constrict. It is present in many places and processes in the body, including the digestive tract and the brain.
Fluctuations in levels of serotonin are a known cause for changes in mood, and, accordingly, many medications for depression are focused on treating the activity of serotonin.
In the research by de Boer and his fellow scientists, undomesticated mice and rats were used to study the changes in the chemicals in the aggression-related circuits of the brain, specifically those involved with serotonin. This was accomplished by allowing the rodents to repeatedly physically dominate other mice and rats, thereby provoking them to acquire violent characteristics subject to aggressive behavior.
After this regime, it was found that the rodents' behavior changed from a regular aggressiveness to the more pathological sort that is found in pathologically violent humans. It was during this "change" that the scientists reviewed the fluctuations in the brain chemicals, and found that the repeated "victories" of the conquering rodents over the other rodents produced a decrease in the amount of serotonin activity in those conquering rodents, a decrease that was not due to the regular aggressiveness they had previously displayed.
De Boer stated, "Our findings support meta-analyses of serotonin activity in aggressive humans. That data showed that serotonin deficiency is most readily detected in people who engage in impulsive and violent forms of aggressive behavior rather than in individuals with more functional forms of aggression."
Written by Falishia Sloan
Reviewed by Emma Wear
Published by Pooja Ghatalia