exhaustion and pain that kept her on the couch much of the day. The 58-year-old Seattle speech coach didn’t want to take opioid pain-killers, but Tylenol wasn’t helping enough. Roth was intrigued when women in her online chat group enthused about a cannabis-derived oil called cannabidiol (CBD) that they said relieved pain without making them high. So Roth, who hadn’t smoked weed since college but lived in a state where cannabis was legal, walked into a dispensary and bought a CBD tincture. “Within a few hours of placing the drops in my mouth, the malaise and achiness that had plagued me for weeks lifted and became much more manageable,” she says. She took the drops several times a day and in a few weeks was back to her regular life.
There is reasonable evidence from prospective epidemiological studies which suggests that cannabis use can precipitate schizophrenia in persons who are vulnerable because of a personal or family history of schizophrenia. There is also evidence that a genetic vulnerability to psychosis increases the risk that cannabis users will develop psychosis (McGuire et al., 1995; Arseneault et al., 2002; Verdoux et al., 2002). A casual relationship also has biological plausibility in that the cannabinoid and dopaminergic neurotransmitter systems interact in animals. D'Souza and colleagues (1999) have shown in a provocation study that THC produces a dose-dependent increase in psychotic symptoms under double-blind placebo conditions; and Caspi and colleagues (2005) have shown an interaction between specific alleles of the COMT allele and psychotogenic effects of cannabis. If these results can be replicated and extended, they will increase the likelihood that cannabis can be a contributory cause of psychosis in vulnerable individuals.
Cannabis lowers the pressure in the eye that causes optic nerve damage leading to glaucoma. Research has shown conclusively that marijuana users experience lower internal eye pressure while the body metabolizes THC. However, the psychoactive side effects of using THC to treat glaucoma make cannabis a nonviable medication for most people with the disease.

The market is rife with misinformation even when CBD is sold as a relatively simple oil or supplement. When it’s squirted into a latte or baked into a cookie, CBD’s uses and effects get even more opaque. The chemical’s loudest advocates make health claims far beyond the current scientific evidence, and its harshest critics often dismiss the compound entirely as just another snake oil in America’s long tradition of health scams. Journalists are starting to get a handle on what CBD actually does and what is actually known about it, but along with researchers and regulators, we’re still playing catch-up when it comes to the people who have pushed the compound into what feels like mainstream overnight success: entrepreneurs.
Cannabis use started to become popular in the United States in the 1970s.[252] Support for legalization has increased in the United States and several U.S. states have legalized recreational or medical use.[282] A 2018 Social Science Research study found that the main determinants of such changes in attitudes toward marijuana regulation since the 1990s were changes in media framing of marijuana, a decline in perception of the riskiness of marijuana, a decline in overall punitiveness, and a decrease in religious affiliation. [283]