COCAINE SHORT-CIRCUITS PLEASURE, STUDY FINDS

NEW YORK - Chronic cocaine use harms brain circuits that help produce the
sense of pleasure, which may help explain why cocaine addicts have a higher
rate of depression, a study suggests.

It's not clear whether cocaine kills brain cells or merely impairs them, or
whether the effect is reversible, said study author Dr. Karley Little. But
it's bad news for cocaine addicts in any case, he said.

"I personally wouldn't want to lose 10 or 20 percent of my reward-pleasure
center neurons, or have them just deranged or not working right," said
Little, of the Ann Arbor, Mich., Veterans Affairs Medical Center and the
University of Michigan.

He and colleagues studied brain samples taken during autopsies from
long-term, heavy cocaine users. Their results are reported in the January
issue of the American Journal of Psychiatry.

Little said the research did not reveal whether the brain impairment
resulted from years of use or just recent use.

The research provides "a piece of the puzzle" in explaining why cocaine
users run a higher risk of depression, said Dr. Deborah Mash, a
neuroscientist at the University of Miami School of Medicine.

It remains unclear whether cocaine causes depression or whether people
start using the drug because they are depressed.