A safer cannabis extract could help users fight cannabis dependence, according to a new clinical trial.
The National Institute on Drug Abuse note that about 30% of recreational cannabis users in the United States "may have some degree of marijuana use disorder" that symptoms of dependence often characterize.
Dependence causes a person to compulsively seek the drug, as they experience withdrawal symptoms when they do not have access to it. Irritability, sleep problems, and poor appetite can be among these symptoms.
Yet researchers from the University of Sydney and the New South Wales Ministry of Health in Australia point out that existing treatments for cannabis dependence are not always effective.
To address this issue, the team tested a new medicinal drug that is meant to be more effective in treating cannabis dependence than existing therapies.
In a new clinical trial — whose results the researchers report in JAMA Internal Medicine — they assessed the drug's effectiveness and safety for humans. This new medication is a cannabinoid agonist drug consisting of a cannabis extract that works by interacting with cannabinoid receptors in the brain.
These receptors are part of the endocannabinoid system, and their main role is to synthesize the substances that form part of ingested cannabis. By targeting them, the researchers hope to reduce the rate of relapse of people who seek treatment for cannabis dependence.
"We've never had the evidence before that medication can be effective in treating cannabis dependency — this is the first big study to show this is a safe and effective approach," says lead author Prof. Nick Lintzeris.
"The principles are very similar to nicotine replacement; you are providing patients with a medicine, which is safer than the drug they're already using, and linking this with medical and counseling support to help people address their illicit cannabis use," Prof. Lintzeris explains.
'Effective substitute for smoked cannabis'
The therapeutic compound contains nabiximols, which are equal parts cannabidiol (CBD) and tetrahydrocannabinol (THC), which is the main psychoactive ingredient in cannabis.
Prof. Lintzeris and team tested this drug in 128 volunteers — 30 women and 98 men — with a mean age of 35 years. All the participants were recreational cannabis users who had sought treatment for dependence but who had previously been unsuccessful in stopping their recreational drug use.
The researchers gave the nabiximols medication to the participants over 12 weeks. The users administered the drug in spray form, delivering it orally, under the tongue. The researchers gave each participant an average dose of 18 sprays per day; each spray was 0.1 milliliters, containing 2.7 milligrams (mg) of THC and 2.5 mg of CBD.
Prof. Lintzeris and team followed up with the participants at baseline, and then again after 2, 4, 8, and 12 weeks. Throughout the trial period, the participants also had cognitive behavioral therapy (CBT) and other forms of therapeutic support, as necessary.
The researchers found that participants who they had given nabiximols to started using significantly less illicit, recreational cannabis than the control group who they gave a placebo.
This replacement strategy, the study authors explain, also benefits individuals by removing their normal patterns of recreational drug use.
"Worldwide, we are seeing medicinal cannabis patients transition away from the traditional smoked route of cannabis administration; this new study [...] complements this trend by showing that an oral spray can be an effective substitute for smoked cannabis in heavy recreational users seeking treatment for their cannabis use."
Study co-author Prof. Iain McGregor
The current results come hot on the heels of another study that the same research team led, which showed that nabiximols effectively reduced cannabis withdrawal symptoms in a short-term, in-hospital treatment program.
However, the latest study, "is even more important in that it shows that nabiximols can be effective in helping patients achieve longer term changes in their cannabis use," Prof. Lintzeris emphasizes.
"Our study is an important step in addressing the lack of effective treatments — currently, four in five patients relapse to regular use within six months of medical or psychological interventions," he continues.