Studies Show Marijuana Can Harm Young Users' Brains

A study suggests that marijuana can cause potentially harmful changes in the brains of young users related to motivation and emotion.

The study, a collaboration between Northwestern University's medical school, Massachusetts General Hospital and Harvard Medical School, showed correlations between abnormalities in the brain and the number of times users smoked marijuana.

Co-senior study author Dr. Hans Beiter, professor of psychiatry and behavioral sciences at Northwestern University, said, "What we're seeing is changes in people who are 18 to 25 in core brain regions that you never, ever want to fool around with."