Scott Shannon, MD, assistant clinical professor at the University of Colorado, recently sifted through patient charts from his four-doctor practice to document CBD’s effects on anxiety. His study, as yet unpublished, found “a fairly rapid decrease in anxiety scores that appears to persist for months,” he says. But he says he can’t discount a placebo effect, especially since “there’s a lot of hype right now.”

Then there is the matter of which part of the plant is used. THC tends to be more concentrated in the leaves of the plant, while CBD in its stem and seeds. It should be noted that these aspects are relative. Some degree of agreement exists that for the purest CBD, the stalk of a hemp plant (varieties of cannabis generally grown for fiber manufacturing, low in THC), or much less often the seeds. Taking into account the fact that CBD supplements are usually in an oil form, one may fathom the origins of the nearly ubiquitous hemp oil dietary supplements.