In virtually every study, marijuana proves to be far less addictive than alcohol, let alone drugs like cocaine or heroin (here is one good summary—scroll down to the comparative ratings). Smoking marijuana does carry the same risks as smoking tobacco — lung and esophageal cancers —but there’s no good data showing that these risks outweigh the risks of liver problems from drinking. And yet we have spent billions of dollars incarcerating people (particularly young black men) for doing nothing more than smoking a joint.