"When states began legalizing marijuana nearly three decades ago, initially for medical use, they set in motion something of an unintended public health experiment...."

"But cannabis remains illegal under federal law and classified as a tightly controlled substance, which has stymied oversight and scientific study.... [Few states] require warnings about cannabinoid hyperemesis syndrome or psychosis. None are monitoring — or are even equipped to assess — the full scope of health outcomes. 'There is no other quote-unquote medicine in the history of our country where your doctor will say, "Go experiment and tell me what happens,"' said Carrie Bearden, a clinical psychologist and neuroscientist at the University of California, Los Angeles.....  The commercial industry that followed [legalization] touted its products as beneficial, while focusing not on developing marijuana’s medical uses but on engineering a quicker, more intense high.... The commercial market expanded further in 2018 when Congress legalized hemp, a cannabis plant used in industrial products, and inadvertently legalized highly intoxicating hemp-derived compounds like Delta-8 THC...."

From "As America’s Marijuana Use Grows, So Do the Harms/The drug, legal in much of the country, is widely seen as nonaddictive and safe. For some users, these assumptions are dangerously wrong" (NYT).