What Marijuana Might Do to Your Brain

The stoner character may be more than stereotype: Smoking pot may actually make you lazy. Occasional marijuana use can affect your motivation, according to a recent study from Harvard Medical School.

Out of 40 college students, the half who smoked pot once or twice a week for a few months showed more changes in the brain areas regulating emotion, mental illness, and motivation than the drug-free undergrads. “Your motivation levels determine whether or not you get out of bed in the morning,” says study coauthor Anne Blood, Ph.D. "And we're seeing some pretty convincing changes in these regions.”