CBD is one of 80 chemicals in cannabis. It does not give the “high” typically associated with cannabis, which comes from tetrahydrocannabinol (THC).
In the first double-blind, placebo-controlled study (where neither the participants nor the researchers know who is receiving the real treatment or the placebo), Tom Freeman of the University of Bath in the UK and colleagues aimed to determine the optimal dosage of prescription-grade CBD for cannabis use disorder.
Prescription or medical-grade CBD is manufactured at high purity levels, and is free of fillers and other toxic ingredients; it can also be much stronger than over-the-counter versions.
The study found the 200-milligram dosage to be ineffective, however both 400 mg and 800 mg per day did significantly reduce marijuana dependence when compared with a placebo.
People in the study used cannabis about half a day per week less when they got 400mg of CBD daily, and just under a third of a day per week less after 800 mg of CBD daily.
However, do not do this at home — the researchers cautioned against self-medicating with commercial CBD products, which typically contain about 25 mg of CBD.
Freeman and colleagues measured CBD impact on cannabis use by measuring THC in urine and the average number of days per week volunteers could go without using cannabis. The team found that CBD was more effective than the placebo treatment on both accounts. Participants also received six counseling sessions focused on helping them quit using cannabis.
Though the month-long study of 82 participants was not designed to determine the duration or efficacy of CBD treatment, the findings suggest CBD can help people reduce cannabis use, the researchers said.
There were no serious adverse events during the study, and the researchers say CBD use is safe. They believe their findings could have implications for the treatment of cannabis use disorder as medical and recreational use of cannabis is being increasingly legalized.
Experts agree the results of the study are promising.
“Sadly, there currently is practically no treatment available for people with cannabis use disorder in the UK,” said Robin Murray, a psychiatric research professor at King’s College London, who was not involved in the study. “This study shows that high doses of CBD may be helpful.”
Freeman and colleagues call for additional research to determine the duration and efficacy of CBD in treating cannabis use disorder. They say further research could also help determine whether CBD directly reduces cannabis use or reduces other mental health issues, which could indirectly affect cannabis use.