WASHINGTON (Reuter) Longterm marijuana use produces changes in the brain
that may make users more vulnerable to addiction to other drugs such as
cocaine, heroin and alcohol, according to a study.

The study by the National Institute on Drug Abuse also provided evidence
marijuana can be addictive, the U.S. National Institutes of Health said.

"The finding from this and other studies ... suggests that addiction to one
drug may make a person more vulnerable to abuse and addiction of other
drugs," said George Koob, a researcher with the Scripps Research Institute
in San Diego.