The recent FDA approval of Epidiolex, the CBD-based drug for epilepsy, is the furthest anyone has come in establishing efficacy of CBD for any condition.
But researchers from major educational institutions, including Johns Hopkins and the University of California at San Diego, are studying an array of potential uses.
One important area: opioid addiction. Some animal studies and early research in humans suggest that CBD may help treat that problem and other forms of substance abuse. Other reports show that states with medical marijuana laws have seen drops in the rates of opioid deaths and use, possibly as people turn to cannabis products (which include CBD) as alternatives.
Scientists blame the current paucity of definitive evidence not necessarily on the ineffectiveness of cannabis or CBD, but on government rules that for years prevented scientists from using federal money to research the compound’s possible health benefits.
That’s why the approval of Epidiolex may well open up a path to more research on CBD. In fact, some restrictions have recently been lifted. Last year, the National Institutes of Health awarded $140 million toward cannabis research, with $15 million going to CBD studies.
Until evidence from this new research emerges, however, conclusive findings are hard to come by. Ryan Vandrey, Ph.D., a Johns Hopkins researcher investigating the potential health benefits of CBD, says: “Other than epilepsy, at this point [the benefits are] mostly postulation, not proof.”
Donald Abrams, M.D., a cancer specialist and practitioner of integrative medicine at Zuckerberg San Francisco General Hospital, is a co-author of a 2017 report on the medical benefits of cannabis from the National Academies of Science, Engineering, and Medicine. When he and 15 other experts examined more than 10,000 studies— based mainly on cannabis in general, not just CBD—they found only three conditions for which the evidence in humans, not lab animals or other forms of preliminary research, was strong: pain, nausea related to chemotherapy, and spasticity in patients with multiple sclerosis.
For CBD alone, the evidence is even more sparse. Abrams says the NAS report, which came out before Epidiolex was approved, could identify only three published randomized trials—the gold standard for medical research—that looked at just CBD. And for none of those conditions—anxiety, smoking cessation, and Parkinson’s disease—was the evidence strong enough for the NAS report to conclude that CBD clearly helps.
With so little research into CBD, it’s hard to know for certain how safe it is. That may be particularly concerning for pregnant or breastfeeding women.
Still, the research to date has identified few risks. It appears to be safer than THC, with even the FDA saying CBD poses little risk of abuse. Side effects, however, include tiredness, diarrhea, and changes in appetite and weight.
It’s also unclear what doses or forms of CBD might work best for which conditions, notes Joseph Maroon, M.D., a clinical professor of neurological surgery at the University of Pittsburgh Medical Center who authored a recent review of the neurological benefits of CBD alone and with THC. He writes that with more than 1,000 CBD and cannabis products on the market, in multiple forms, “dosing recommendations are nearly impossible.”
And most medical studies have used doses of CBD much higher than what’s included in products consumers typically purchase, according to ConsumerLab, a company that tests health and beauty products. In addition, some research suggests CBD may interact with several kinds of prescription meds.
If you want to try CBD, talk with your doctor first, especially if you take any prescription drugs or are pregnant or breastfeeding. Until more evidence comes in, be wary of turning to CBD in lieu of more proven therapies, especially for serious health problems, such as cancer.
Though it’s unclear what dosage might work best for any health problem, it’s worth looking for products that say they contain CBD, not just “cannabinoids.” Products that say they contain that broader class of compounds may not have much if any CBD. Instead, they may contain a mix of more than 100 other compounds found in cannabis plants, about which even less is known. In addition, look for products that list the amount of CBD per serving, not just per bottle.