Cannabidiol (CBD) -- an active compound in cannabis -- has attracted a lot of attention in recent years for its purported health benefits, but the medical research about just what those benefits may be is still ongoing. So far, the clearest evidence that CBD has helped patients has come from its use as an anti-seizure treatment for young people with certain types of epilepsy.

Now, a study conducted out of the Children's National Hospital in Washington, D.C., has found that not all forms of CBD work the same way. "Our research indicates that pharmaceutical CBD may indeed be more effective than artisanal CBD," says the study's lead author, Dr. Nathan T. Cohen.

Artisanal products contain varying concentrations of CBD, and also contain tetrahydrocannabinol (THC) -- the psychoactive compound in cannabis. Pharmaceutical CBD, by contrast, contains no THC. In a study on children with epilepsy, those who used artisanal CBD actually saw a 70% increase in seizures while those who used pharmaceutical CBD had a 39% decline in seizures. 

While Cohen found the results concerning, "since many people continue to use artisanal CBD," the study was fairly small, with just 31 children and teens participating. In addition, 11 of the participants experienced side effects, and all were among the group using pharmaceutical CBD. (In the study, 22 patients were given pharmaceutical CBD; the remaining nine took artisanal CBD.)

Prescription medication.

Image source: Getty Images.

Strong demand for CBD-based medicines

Cannabis-based medicines are still a rarity in the U.S. -- the Food and Drug Administration (FDA) has thus far only approved Epidiolex, a drug made by GW Pharmaceuticals (NASDAQ:GWPH), for the treatment of certain seizures. 

The company's year-end results, released on Feb. 25, showed Epidiolex sales reaching $296.4 million during the drug's first full year on the market. GW expects more growth in 2020 as it launched Epidiolex commercially in Germany in Q4 2019 and plans to launch it in the U.K., Spain, France, and Italy this year.

Shares of GW are down more than 42% over the past year, but that's better than the 67% decline that the Horizons Marijuana Life Sciences ETF has experienced during the same period.