MITCH RUSTAD
New York Times Syndicate - January 14, 2000 The four-year study led by Keith McBurnett,
assistant professor of psychiatry at the University of Chicago, looked at boys
with a history of behavioral problems. The researchers found that those with
consistently low cortisol levels began antisocial acts at a younger age.
They also exhibited three times the number of
aggressive symptoms, and were three times as likely to be singled out by their
classmates as being mean or combative as those who had higher or fluctuating
cortisol concentrations in their saliva.
For four years, the researchers followed 38
boys who had been referred to a psychiatric clinic because of their disruptive
behavior. They collected saliva samples from each boy in years two and four of
the study.
Through psychiatric evaluations and interviews
with parents and teachers, the researchers assessed the boy's aggressive
behaviors and tallied symptoms such as starting fights, using weapons, being
cruel to people or animals, stealing and forcing sexual acts.
The study findings suggest that there is a
lasting biological, and not just parental or short-term environmental, component
to this type of chronic antisocial behavior, according to McBurnett.
``Children with persistent conduct disorder
may have genes that predispose them to produce certain hormones differently, or
their hormone production may have been altered before or soon after birth,''
said McBurnett.
Each child in the study was also evaluated by
his peers at school; classmates were asked to rate all their fellow students on
several behavioral categories, including naming the three boys in class who were
meanest and fought most. The study is published in the January issue of Archives
of General Psychiatry.
The researchers found that salivary cortisol
levels were ``strongly and inversely related to aggressive conduct disorder,
peer aggression nominations and oppositional defiant disorder.''
The 12 boys with low cortisol levels on both
samples averaged 5.2 symptoms of conduct disorder, compared to 1.5 such symptoms
in the 26 boys who had a higher level on either sample. More than one-third of
boys with low cortisol were nominated by their peers as the ``meanest'' in the
class, compared with 10.5 percent of boys who had at least one higher cortisol
reading. Eleven of the 12 boys with consistently low cortisol levels developed
aggressive symptoms before age ten. Less than half of those with at least one
higher cortisol level showed symptoms before age ten.
One mental health professional said more
detailed research is necessary before any conclusions can be drawn between
cortisol levels and aggressiveness in boys.
``I think we should be reserved in how excited
we get,'' said Elizabeth Kandel Englander, associate professor of forensic
psychology at Bridgewater State College in Massachusetts, and author of the book
``Understanding Violence.''
``Aggression very often doesn't occur in
isolation. It usually has cognitive or medical issues, so if you take a
population of children with problems of aggression, you also have other
behavioral problems,'' said Englander. ``It's difficult to see this as an
important causal factor. The only way to tell if low levels of this hormone are
important in understanding aggression is to conduct a long-term study.''
(The Medical Tribune Web site is at http://www.medtrib.com)
c.2000 Medical PressCorps
News Service
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