Professor Carmen Sandi, Head of the Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory of Behavioral Genetics, Director of the Brain Mind Institute, and a member of the National Centers for Competence in Research SYNAPSY, and colleagues are the first to demonstrate a direct genetic link between childhood trauma and violent behavior as an adult. The research was published in the Jan. 15, 2013, issue of Translational Psychiatry.
The scientists examined the brains of rats that had been exposed to psychologically stressful situations when young and found that those rats demonstrated a higher level of aggressive behavior as adults that could be directly related to a permanent change in the rat's brains. The same changes have been shown to exist in traumatized adolescent humans.
"In a challenging social situation, the orbitofrontal cortex of a healthy individual is activated in order to inhibit aggressive impulses and to maintain normal interactions," explains Sandi. "But in the rats we studied, we noticed that there was very little activation of the orbitofrontal cortex. This, in turn, reduces their ability to moderate their negative impulses. This reduced activation is accompanied by the overactivation of the amygdala, a region of the brain that's involved in emotional reactions."
Other researchers who have studied the brains of violent human individuals have observed the same deficit in orbitofrontal activation and the same corresponding reduced inhibition of aggressive impulses.
The deficit in orbitofrontal activation and the same corresponding reduced inhibition of aggressive impulses was traced to an increased expression of the MAOA (Monoamine oxidase A) gene in the prefrontal cortex.
A MAOA gene inhibitor (an antidepressant) was found to reverse the rise in aggression induced by juvenile stress.
This research indicates the potential to prevent violent behavior as an adult caused by traumatic experiences as a juvenile is possible.
The research is pertinent to Birmingham, Alabama as the rate of assaults and murders committed by young adults rose to new levels in 2012.
The research was reviewed at the Eureka Alert website on the date of publication.
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