Last year, the National Academies of Sciences, Engineering and Medicine released a nearly 500-page report on the health effects of cannabis and cannabinoids. A committee of 16 experts from a variety of scientific and medical fields analyzed the available evidence — more than 10,000 scientific abstracts in all. Because so few studies examine the effects of CBD on its own, the panel did not issue any findings about CBD specifically, but it did reach some conclusions about cannabis and cannabinoids more generally. The researchers determined that there is “conclusive or substantial evidence” supporting the use of cannabis or cannabinoids for chronic pain in adults, multiple sclerosis-related spasticity (a kind of stiffness and muscle spasms), and chemotherapy-induced nausea and vomiting. The committee also found “moderate” evidence that cannabis or cannabinoids can reduce sleep disturbances in people with obstructive sleep apnea, fibromyalgia, chronic pain and multiple sclerosis, as well as “limited” evidence that these substances can improve symptoms of Tourette’s syndrome, increase appetite and stem weight loss in people with HIV/AIDs, and improve symptoms of PTSD and anxiety.
Still, as the saying goes, absence of evidence isn’t necessarily evidence of absence, and there’s a reason we don’t have a ton of solid research on CBDs yet — “to study it, we need a good source, ” said Ziva Cooper, who is an associate professor at Columbia University and was on the National Academies committee. CBD is hard to get because it’s still technically a Schedule I drug, which limits its availability, Cooper said.
Donald Abrams was a member of the committee that reviewed the evidence that went into producing the report, and he said that the studies they reviewed overwhelmingly used pharmaceutically available preparations that contain THC, including dronabinol, nabilone and the whole-plant extract spray nabiximols, which contains equal parts CBD and THC. It’s impossible to know whether the benefits of cannabis can also be obtained from CBD alone, Abrams said, because CBD is just one of 400 chemicals present in the plant. So far, CBD in isolation has been studied in only a handful of randomized, placebo-controlled trials (considered the gold standard of evidence in medical research), and the evidence remains sparse.
But, uh, what is it that CBD is supposed to do? I visited a cannabis dispensary in Boulder to find out what the hype was all about. After passing an ID check, I was introduced to a “budtender” who pointed me to an impressive array of CBD products — tinctures, skin patches, drink powders, candies, salves, massage oil, lotions, “sexy time personal intimacy oil” and even vaginal suppositories to treat menstrual cramps.
In the meantime, some physicians are forging ahead — and cashing in. Joe Cohen is a doctor at Holos Health, a medical marijuana clinic in Boulder. I asked him what CBD is good for, and he read me a long list of conditions: pain, inflammation, nausea, vomiting, intestinal cramping, anxiety, psychosis, muscle spasms, hyperactive immune systems, nervous system degeneration, elevated blood sugar and more. He also claimed that CBD has anti-cancer properties and can regenerate brain cells and reduce the brain’s levels of amyloid beta — a kind of protein that’s been linked to Alzheimer’s disease. I asked for references, noting that most of these weren’t listed in the Academies report or a similar review published in the Journal of the American Medical Association. “I think you just have to Google search it,” he said. It’s true that a preliminary study found hints that cannabinoids might reduce beta amyloid proteins in human brain cells, but the study was done in cells grown in a lab, not in people. As for cancer, the FDA sent warning letters last year to four companies that were selling products that claimed to “prevent, diagnose, treat or cure” cancer.
Cannabidiol, or CBD, is the lesser-known child of the cannabis sativa plant; its more famous sibling, tetrahydrocannabinol, or THC, is the active ingredient in pot that catapults users’ “high.” With roots in Central Asia, the plant is believed to have been first used medicinally — or for rituals — around 750 B.C., though there are other estimates too.
This year, 1,090 people have contacted poison control centers about CBD, according to the American Association of Poison Control Centers. Over a third are estimated to have received medical attention, and 46 were admitted into a critical care unit, possibly because of exposure to other products, or drug interactions. In addition, concern over 318 animals poured into the American Society for the Prevention of Cruelty to Animals’ Animal Poison Control Center.
What are the claims?
While there is hope for treating other conditions with the plant extract, Epidiolex remains the only CBD-derived drug approved by the F.D.A. Most of the research on cannabidiol has been in animals, and its current popularity has outpaced science. “We don’t have the 101 course on CBD quite figured out yet,” said Ryan Vandrey, an associate professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine.
But without clinical trials in humans, psychologists say CBD’s effect on depression is still a hypothesis, and not an evidence-based treatment.
However, a double-blind study found healthy volunteers administered CBD had little to no change in their emotional reaction to unpleasant images or words, compared to the placebo group. “If it’s a calming drug, it should change their responses to the stimuli,” said Harriet de Wit, co-author of the study and a professor in the University of Chicago’s department of psychiatry and behavioral neuroscience. “But it didn’t.”
But does it work? And does taking CBD do us any good? Philip McGuire is a professor of psychiatry and cognitive neuroscience at King’s College London; he has a special interest in psychosis and started looking into cannabidiol about 15 years ago. One of the first experiments he worked on looked at how cannabidiol works in the brains of healthy people in comparison with the impact that THC has. The results were categoric. “We basically showed that the two compounds have opposite effects on brain function,” says McGuire. “So when THC is making you psychotic, it stimulates certain bits of the brain. And in these areas of the brain, CBD has the opposite effect, essentially, in the same people.” To boil it down: “CBD and THC seem to be pushing in opposite directions.”
Hearing these testimonies, it would seem perverse, even neglectful, not to use CBD, but where to start? One option is High Tea at Farmacy, a plant-based restaurant in west London. On the menu are a CBD-infused vodka cocktail, CBD truffles (tahini and dark chocolate, and basmati and coconut) and a pot of hemp leaf tea. With extras, it costs £42. “You don’t technically get high from it, it’s just a great play on words,” says Camilla Fayed, who opened Farmacy in 2016. “It definitely draws people in.”
Anecdotal evidence suggests that CBD use skews towards the young and female, but Horn at LDN CBD hasn’t found a gender divide and he has lots of older customers in his shop. He often hears that CBD oil helps with their arthritis, and sometimes that they have been able to open jars for the first time in years. Horn has even got his granny on CBD. He is currently raising funding for two more stores in London, and he would like to have another 10 stores in the major cities of the UK. “Most towns with a Holland & Barrett could have a shop like this,” he predicts.
Fayed, the 34-year-old daughter of former Harrods owner Mohamed Al Fayed, first came across CBD in the US in an oil made by Charlotte’s Web. The company is named after Charlotte Figi, a 12-year-old with Dravet syndrome, whose story has many echoes of Billy Caldwell’s. Figi, too, found that her seizures were significantly reduced by taking medical cannabis. Charlotte’s Web was developed in 2011 by six brothers (Joel, Jesse, Jon, Jordan, Jared and Josh Stanley) who crossbred a strain of marijuana with industrial hemp to make products that are high in cannabidiol and low in THC. Its oils start with the entry-level “full strength”, which claims 6.65mg of CBD per ml, and go up to “maximum strength”, which has 60mg of CBD per ml.
Something, though, is missing from the CBD story: proof. And this is the detail that really worries Professor McGuire. He points out that in the trials on psychosis that he’s been involved in, patients might be given 1,000mg of pure cannabidiol in a tablet; the medication for the pharmaceutical treatment of epilepsy could be 2,500mg. Compare this to a drink advertised as CBD coffee or a brownie, which may contain, for example, 5mg of CBD. And there is the issue of bioavailability: how much of a drug your body actually takes into your gut. “Of that 5mg, you might absorb 1mg or less,” says McGuire. “Or none.”