Take this quiz to see how much you know about marijuana.

1. It’s impossible to overdose on marijuana.

TRUE. To the best of our knowledge, no one has ever died from a marijuana overdose. In technical jargon, marijuana has no level of acute toxicity. But this doesn’t mean it’s safe. There is still the possibility of slamming your car into a lamppost while stoned or getting a joint that is laced.

2. Marijuana is not addictive.

FALSE. Research shows that marijuana is addictive. Believe it or not, each year, more young adults enter drug treatment with a primary diagnosis of marijuana dependency than for all other illicit drugs combined. One recent study found that when abstaining from marijuana for just three days, regular users experienced withdrawal symptoms like insomnia, drug cravings, anger, irritability, and aggression.

3. Marijuana has become less popular among college students recently because of Ecstasy and prescription drug abuse.

FALSE. Far more young people use marijuana than any other drug, even with the rise in prescription drug abuse. Among young people who use drugs, approximately 60% use marijuana only.

4. Smoking one joint is just the same as smoking one cigarette.

FALSE. Smoking one joint is equal to smoking five cigarettes — smoking four joints is like smoking an entire pack. Because marijuana smokers tend to take longer, deeper drags and hold smoke in their lungs for longer, they end up with three to five times more tar and carbon monoxide in their bodies. Plus, marijuana is usually smoked unfiltered (in joints, blunts, bongs, and pipes) and burns at a higher temperature, which is more damaging to the lungs.

According to the American Cancer Society, many of the cancer-causing substances in tobacco are also found in marijuana. Medical reports suggest marijuana may cause cancers of the mouth and throat. Ultimately, it has been hard to prove a connection between marijuana and lung cancer because it is not easy to gather information about the use of illegal drugs. Also, many marijuana smokers also smoke cigarettes. This makes it difficult to know how much of the risk is from tobacco and how much is from marijuana.