Stress, Aggression Bound Tightly Together

One reinforces the other, explains uncontrolled rage, study says

MONDAY, Oct. 4, 2004 (HealthDayNews) -- A biological link between stress and aggression may help explain why humans can become enraged and violent so easily and find it difficult to calm down, says a study in the October issue of Behavioral Neuroscience.

Behavioral neuroscientists in the Netherlands and Hungary found that rats have a fast, mutual, positive feedback loop between the aggression control center in their brains and their stress hormones. The neurophysiology of rats is similar to that of humans.

In experiments with 53 male rats, the researchers tested whether stimulating the rats' aggression mechanism raised blood levels of a stress hormone. The researchers also tested whether higher levels of that stress hormone led to a response in the brain's aggression mechanism.

The results indicated a fast-acting feedback loop between the stress hormone and the aggression mechanism. This suggests that stress and aggression may be mutually reinforcing and may explain why, for example, the stress of traffic jams can lead to road rage in humans.

"It is well known that these stress hormones, in part by mobilizing energy reserves, prepare the physiology of the body to fight or flee during stress. Now it appears that the very same hormones 'talk back' to the brain in order to facilitate fighting," study author Menno Kruk, from the Leiden/Amsterdam Center for Drug Research, said in a prepared statement.

The findings could help researchers find ways to prevent pathological violence in humans.

More information

The National Youth Violence Prevention Resource Center has advice about teen anger management.

SOURCE: American Psychological Association, news release, Oct. 3, 2004
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