STUDY: PRENATAL COCAINE LINKED TO BRAIN DAMAGE

WASHINGTON (Reuters) - Cocaine use by pregnant women may result in
the loss of more than half the brain cells in the infant's cerebral
cortex, the highest level of the brain, researchers said on Thursday.

Researchers studied the brains of rhesus monkeys, but scholarly
commentators said the findings could have implications for humans
about actual physiological damage to the infant brain linked to
prenatal cocaine use by the mother.

Half the eight monkeys in the experiment were born to mothers who got
20mg/kg of cocaine per day during the second trimester of pregnancy.
The other half got no cocaine, but had similar diet and prenatal care.

The study, published in the Journal of Comparative Neurology, found
the cerebral cortex of the drug-treated monkeys contained about 60
percent fewer neurons and was about 20 percent smaller than that of
the control monkeys.

``This is the first study that clearly shows the possibility that
cocaine may affect the brain structure. It shows that it could
happen,'' said Dr. Michael Lidow of the University of Maryland's
Program of Neuroscience, one of the study's authors.

``This is a warning sign,'' Lidow said.

Generated during the second trimester of monkeys and humans, the
cerebral cortex is largely responsible for higher brain functions,
including sensation, voluntary muscle movement, thought, reasoning
and memory.

Isolating The Effects Of Cocaine

Exposure to cocaine prevents a substantial population of neurons from
reaching their proper position in the cerebral cortex, Lidow said.
For example, researchers know cells born on day 70 of the second
trimester should go to position 5. But the study found cocaine use
blocked the cells from reaching their intended position.

``(We found) a lot (of neurons) actually stayed under the cortex in
the white matter,'' Lidow said, adding the same effect has been
observed in many schizophrenic patients.

Performing the study on monkeys made it easier to pinpoint the exact
effect of cocaine on the brain, Lidow said. At three years, the
monkeys were put to sleep and the cerebral hemispheres of both groups
of animals were analyzed for discernible differences, the study says.

Human studies are difficult to interpret because there are many other
factors that could contribute to the overall effect, including
multiple drug use, a poor diet and other risky behavior, the study
said.

``Monkeys are the closest you could get to humans,'' Lidow said.

Lidow said further research was needed to determine how the findings
may apply to humans.

The study may imply significant repercussions for the long-term
neurological development of humans exposed to cocaine in the fetal
stages, said Dr. Barry Kosofsky of Massachusetts General Hospital and
Dr. Steven Hyman of the National Institute of Mental Health, in a
commentary in the journal.

Kosofsky and Hyman argued that the findings are likely transferable
to human cocaine exposure because of the evolutionary closeness
between primates and humans and the three-year length of the study.

``We certainly have enough information to make it a priority to
identify and treat addicted individuals who are pregnant and to make
serious ameliorative efforts aimed at their children,'' they said.