Fact: Kids who use marijuana are statistically more likely to go on to use other drugs, but that doesn't mean marijuana use causes use of other drugs. The same factors driving marijuana use probably explain use of other drugs. A report by the Institute of Medicine found "no conclusive evidence that the drug effects of marijuana are causally linked to the subsequent abuse of other illicit drugs."

Sources: Institute of Medicine, Time, Marijuana Legalization: What Everyone Needs to Know