As of March 2021, marijuana is legal for all adults in 16 states. Thirty-six states, the District of Columbia and three U.S. territories have medical marijuana programs, while 11 other states allow the use of low-THC cannabidiol products for medical reasons. Only 6 states remain where marijuana is fully illegal.
As the legality of weed increases, more people could try out the drug, while existing users may increase their usage. This means health experts and marijuana users alike are wondering: How safe is marijuana, really?
There is some preliminary evidence that marijuana use is associated with increased risk for mental health disorders like psychosis and depression. States that have legalized marijuana have seen an uptick in car crashes. But the biggest outstanding question seems to be whether marijuana use, especially smoking it, causes cancer in the same way as smoking cigarettes.
