A few drops of CBD oil in a mocha or smoothie are not likely to do anything, researchers contend. Doctors say another force may also be at play in people feeling good: the placebo effect. That’s when someone believes a drug is working and symptoms seem to improve.
Up in the wee hours of the night, stuck watching videos of puppies? CBD may be promising as a sleep aid; one of the side effects of the Epidiolex trials for epilepsy was drowsiness, according to Mr. MacKillop, a co-author of a review on cannabinoids and sleep. “If you are looking for new treatments for sleep, that may be a clue,” he said.
Recently, the F.D.A. sent a warning letter to Curaleaf Inc. about its “unsubstantiated claims” that the plant extract treats a variety of conditions from pet anxiety and depression to cancer and opioid withdrawal. (In a statement, the company said that some of the products in question had been discontinued and that it was working with the F.D.A.)
Is CBD harmful?
“Our top therapies attempt to break the association between reminders of the trauma and the fear response,” said Mallory Loflin, an assistant adjunct professor at the University of California, San Diego and the study’s principal investigator. “We think that CBD, at least in animal models, can help that process happen a lot faster.” While large clinical trials are underway, psychologists say there isn’t compelling evidence yet as to whether this is a viable treatment.
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.
CBD is advertised as providing relief for anxiety, depression and post-traumatic stress disorder. It is also marketed to promote sleep. Part of CBD’s popularity is that it purports to be “nonpsychoactive,” and that consumers can reap health benefits from the plant without the high (or the midnight pizza munchies).
Last year, the F.D.A. approved Epidiolex, a purified CBD extract, to treat rare seizure disorders in patients 2 years or older after three randomized, double-blind and placebo-controlled clinical trials with 516 patients that showed the drug, taken along with other medications, helped to reduce seizures. These types of studies are the gold standard in medicine, in which participants are divided by chance, and neither the subject nor the investigator knows which group is taking the placebo or the medication.
Common symptoms include:
According to a 2017 study in the Journal of the American Medical Association, only 30.95% of CBD products sold online were correctly labeled. Most contained less CBD than advertised, while 21.43% had significant amounts of THC.
CBD oil may also increase liver enzymes (a marker of liver inflammation). People with liver disease should use CBD oil with caution, ideally under the care of a doctor who can regularly check blood liver enzyme levels.
Possible Side Effects
CBD shows promise in the treatment of anxiety disorders, suggests a 2015 review of studies in the journal Neurotherapeutics. According to the investigators, CBD demonstrated potent anxiolytic (anxiety-relieving) effects in animal research, albeit with counterintuitive results.
Part of this response could be explained by the way that CBD acts in the brain. In low doses, CBD may act as an agonist to several receptor sites, meaning it acts similarly to surrounding molecules that normally bind to the receptor, enhancing the signalling of those receptor sites. At higher doses, however, too much activity at the receptor site can lead to an opposite effect, negating the beneficial effects of CBD.
Among the few human trials evaluating CBD’s anxiolytic effects was one published in the Brazilian Journal of Psychiatry in 2019. For this study, 57 men were given either CBD oil or a placebo before a public-speaking event. Anxiety was evaluated using physiological measures (such as blood pressure, heart rate, etc.) and a relatively reliable test for mood states known as the Visual Analog Mood Scale (VAMS).
CBD oil may benefit those with drug addiction, suggests a 2015 review of studies published in Substance Abuse.