CBD research is still in its infancy because both the substance itself and the cultivation of the plants from which it’s derived have long been illegal in the United States. And despite all those cookies you see for sale, CBD does seem to remain illegal, unless FDA approved. In December, hemp cultivation was legalized nationwide as a provision of the Agriculture Improvement Act of 2018. But the FDA released a statement explicating the agency’s stance on CBD’s legality: In short, the FDA does not recognize a distinction between cannabis- and hemp-derived CBD and, for the time being, considers both to be illegal—especially as a questionably safe food additive. Although CBD isn’t dangerous to healthy people, it can affect how the body metabolizes certain types of medication, which Blessing says could lead to overdose in some cases. (Because of the government shutdown, the FDA is unavailable to explain its stance or enforcement plans in further detail.)
CBD has proven neuroprotective effects and its anti-cancer properties are being investigated at several academic research centers in the United States and elsewhere. A 2010 brain cancer study by California scientists found that CBD “enhances the inhibitory effects of THC on human glioblastoma cell proliferation and survival.” This means that CBD makes THC even more potent as an anticancer substance. Also in 2010, German researchers reported that CBD stimulates neurogenesis, the growth of new brain cells, in adult mammals.
Cannabis use started to become popular in the United States in the 1970s. Support for legalization has increased in the United States and several U.S. states have legalized recreational or medical use. 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.