Stress Hormone Linked to Severe Aggression in Boys
Jan. 13, 2000 (Indianapolis) -- A study published in the January edition of the Archives of General Psychiatry indicates that low levels of the stress hormone cortisol in the saliva may be an indicator of persistent aggression in boys. This may indicate a lasting biological component to this type of aggression, meaning that it's not just initiated by parental or environmental factors. <
A group of 38 boys, aged 7-12, who were referred to a clinic for disruptive behavior were studied for up to four years. The researchers conducted psychiatric evaluations on the boys and interviewed family members and teachers looking for symptoms of aggressive behavior such as starting fights, using weapons, and being cruel to people or animals. In addition, classmates were surveyed and asked to name the three children they thought best fit each of five categories: likes most, likes least, fights most, meanest, and most shy. Nominations from the 'fights most' and 'meanest' categories were monitored for two years to determine which boys had peer aggression.
Researchers found that low levels of cortisol, a hormone normally secreted by the brain in response to stressful or threatening situations, is associated with persistent and early aggression. Boys with low cortisol concentrations exhibited three times the number of aggressive symptoms and were named most aggressive by peers three times more often when compared with boys who had higher cortisol levels at either sampling time.
"What we think may be going on with these kids is their system doesn't react to stress very quickly or easily," says lead author Keith McBurnett, PhD, assistant professor of psychiatry at the University of Chicago. "If they don't experience internal stress or anxiety about being punished or retaliated against, that may be reflected in their low levels of stress hormone. This may also explain why punishment doesn't seem to change the aggressive behavior in these kids."
According to McBurnett this may soon lead to a way to separate those who will be aggressive into adulthood from those who may just be "going through a phase." The former is much harder to treat. McBurnett suggests that the findings might also lead to developing new methods to channel that aggressiveness in a way that is better tolerated by society.