Preliminary evidence suggests cannabis may be useful in the treatment of substance use disorders, possibly serving as an effective, but less harmful, substitute for pharmaceutical and recreational drugs, with more acceptable side effects. However, at least one expert is sceptical.
A new review suggests that rather than acting as a “gateway” to other, possibly more dangerous substances, there is an “emerging stream of research” suggesting that cannabis may serve as an “exit” drug, with the potential to facilitate a reduction in the use of other substances.
The results of the study also suggest that cannabis may aid in the treatment of anxiety disorders, particularly post-traumatic stress disorder (PTSD), but that it has little effect on self-harm or harm to others and should not be used by those at risk for psychosis.
The results of this analysis suggest that the impact of cannabis on mental health varies across conditions, with potential for both benefits and harms ― similar to other psychoactive medicines, lead author Zach Walsh, PhD, associate professor of psychology, University of British Columbia (UBC), Vancouver, Canada, told Medscape Medical News.
The analysis was published online October 12 in Clinical Psychology Review.
The investigators conducted the review, said Dr Walsh, because many clinicians are uncertain of what to tell their patients about medical cannabis.
“It wasn’t too long ago when the default would have been just a blanket prohibition. If patients said that they’re using cannabis for anxiety or depression or to help them quit drinking, you would have said, ‘Well, stop it; it’s illegal and not right.’ But that doesn’t really hold as much water these days, in the legal cannabis framework and when we’re seeing more and more acceptance of medical use,” he said.
Much more evidence is needed, “but as we wait for clinical research, there’s this pressure on clinicians to have answers, so this review will help us in the meantime.”
For the study, the investigators searched electronic databases for published studies between 1960 and September 2015 of the use of medical or therapeutic cannabis or marijuana to treat a variety of addictions and psychiatric conditions. They 31 studies that related to cannabis for therapeutic purposes (CTP). The studies included 23,850 participants; most of the studies (87%) were cross-sectional .
Using a 10-point scale, the researchers assessed these studies on the basis of outcome, sample selection, and comparability of groups. Most studies were not of high quality methodologically; ratings ranged from 3 to 7, of a possible 11 points, with a median of 4.
Cannabis contains tetrahydrocannabinol (THC), the primary psychoactive component, and cannabidiol (CBD), which can have anti-inflammatory, anxiolytic, and antipsychotic effects.