Early Marijuana Use May Make Teens More Prone to Later Heroin Use

Researchers report in the journal Neuropsychopharmacology that, based on a study of young rats, the marijuana smoked by young teens may affect their brain's development in a way that makes them more likely to use heroin later in life. In experiments, the researcher found that young rats exposed to the active ingredient in marijuana were more likely than other rats were more sensitive to heroin's effects, were more likely to use larger amounts of heroin when offered freely and disturbances in the brain's “reward system,” known as the endogenous opioid system. (Reuters (http://today.reuters.com/news/newsArticle.aspx?type=healthNews&storyID=2006-07-12T174313Z_01_COL263753_RTRUKOC_0_US-POT-HEROIN.xml), 7/12/06)