Chemical linked to aggression

Violent behaviour in young men seems to be linked to an imbalance of body chemistry - the ratio of copper and zinc in the blood plasma, according to American scientists, whose research was published yesterday. Associated work found that returning this ratio to its usual value was linked with improved behaviour

William Walsh, president of the Health Research Institute in Naperville, Illinois, reports the findings of the small-scale study, which examined 153 males aged between three and 20, in the US journal Physiology and Behavior. "Our preliminary findings show that young men who have varying levels of angry, violent behaviour also have elevated copper, and depressed zinc levels," he writes. By contrast, the non-violent control group had normal levels.

Zinc is an essential trace element, which plays a role in disorders such as the skin conditions such as acne and eczema. "This data suggests that violent behaviour is one of those [zinc-related] disorders," said Dr Walsh. Other studies have also found that behaviour improves when the ratios are returned to "normal" values using zinc and other nutrients, he added.