It is difficult to stop the vicious cycle of violence. Researchers have addressed this issue by attempting to discover why stress-induced anger causes people to lash out quickly and struggle with calming down.

The answer may be found in the nervous system.

Through testing, scientists searched to uncover whether it was the brain's aggression mechanism that led to high blood levels of stress hormones, or if high blood levels of stress hormones triggered the brain's aggression mechanism.

Because a rat's neurophysiology is similar to a human's, researchers turned to experimenting on rats to find some answers. They discovered that by raising one variable (stress hormones), the other variable (brain-based aggression) was raised in response.

During Testing, Scientists:

• Conducted tests on a total of 53 rats in five experiments.

• Triggered an aggression-related part of the rats' mid-brain area associated with emotion. During this stimulation, the rats released the stress hormone called corticosterone, similar to that of humans.

• Tested the reverse affect, by injecting corticosterone into the rats, which facilitated stimulation-evoked attack behavior.

Through these experiments, scientists discovered that stress hormones "talk back" to the brain to facilitate fighting. The study also highlighted the possibility that even when stress hormones are stimulated in no relation to fighting, violent behavior results.

These discoveries could explain why the stress of traffic jams could lead to road rage.

The question -- "Can this feedback loop be connected with human aggression?" -- continues to plague scientists. However, additional research is required to find the answer. Discoveries may lead to canceling out therapies intended to reduce violent behavior and introducing a new way of regulating the release of stress hormones. This suggested alternative would lower stress-precipitated violence through medication methods.

Science Daily October 5, 2004