As more states legalize both medical and recreational marijuana, products containing extracts from the plant are appearing on shelves around the country too. Cannabidiol, commonly abbreviated as CBD, is one such compound that’s now available in various formulations at smoke shops, health food stores and dispensaries. Though CBD is extracted from cannabis, unlike another cannabinoid, THC, it does not have psychoactive properties. So why is this compound that doesn’t provide a high so helpful? It’s all about the number of therapeutic effects associated with the substance.
In the Journal of Epilepsy Research in 2017, summarizes three recent placebo-controlled trials for patients with seizures who received a purified CBD product alongside another antiepileptic drug. These studies found that CBD performed better than the placebo with respect to reducing seizure frequency. However, the author writes that the mechanism of action for CBD is unclear; it might work with other drugs to amplify their effects, rather than directly reduce seizures on its own.
A 2014 review of cannabidiol’s potential therapeutic role in epilepsy and other neuropsychiatric disorders similarly presents reports of the efficacy of the compound for these conditions, though it points out that mechanisms of action are not known and data from double-blind, randomized, controlled studies is lacking.
More rigorous studies are coming out — a double-blind, randomized, controlled clinical trial examining the role of cannabidiol as an additional therapy to treat schizophrenia published March 2018 finds that the experimental group had lower levels of psychotic symptoms than the placebo group. The experimental group also were more likely to be rated as improved and “not severely unwell,” by their doctors. Additional studies support the finding that CBD might possess antipsychotic effects, a review published in JAMA in 2015 indicates compared with placebo, cannabinoids were associated with a greater average number of patients showing a complete nausea and vomiting response, and reduction in pain. The report does include two studies evaluating CBD in treatment of psychosis found no difference between the experimental and control groups.
Some think the compound might have anti-anxiety effects. Scholars at the University of Sao Paolo summarize a number of human and animal studies, conclude that the compound “promotes antianxiety effects in humans,” and propose a few potential pharmacological mechanisms through which it might work. Individual studies examine the effects of the substance in patients with social anxiety disorder, fear of public speaking and paranoia, generally finding beneficial effects, though the studies all have relatively small sample sizes.