How Does Marijuana Affect Your Brain?

MICHAEL SMITH: As the debate over the federal law against marijuana goes on, more than 4 in 10 Americans say they've tried the drug at some point. But using recreational pot can affect your mind in risky ways. When you're high on marijuana, it can mess with your short-term memory, attention, and reaction time. It can also distort your senses and make you feel anxious or paranoid. And after the high wears off, you might have trouble learning or sleeping for a little while, too.

So how does pot affect your brain if you use it for a long time? Well, that's not clear. There's simply not much research yet. Long-term use may raise some people's risk for drinking problems, nicotine addiction, and more. And if you have a mental illness, marijuana can make it worse.

Overall, pot-related problems tend to be more serious if you start using the drug heavily in your teens. Research suggests that smoking it daily may even affect your intellectual level. Some good news -- most people who use marijuana don't go on to take harder drugs. For WebMD, I'm Dr. Michael Smith.