Updated on November 22, 2021.
Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
A new study from Australia
did not find strong evidence that cannabis helps psychiatric disorders, and the
authors conclude that the low quality and quantity of evidence does not support
its use. The study appeared in the prestigious journal The Lancet Psychiatry.
But medical marijuana
advocates say the problem is the lack of research rather than the results of studies
that have been conducted, according to an article in US News & World Report.
The researchers included 83
studies—42 for depression, 31 for anxiety, 12 for post-traumatic stress
disorder (PTSD), 11 for psychosis, eight for Tourette’s syndrome and three for
attention-deficit hyperactivity disorder (ADHD). The studies largely used
pharmaceutical THC, which may or may not have contained CBD, a component of
cannabis that has been associated with reduced anxiety.
While the study showed few
positive findings, THC increased the number of people who had adverse events in
10 studies, leading the authors to warn patients about the risks of using
“These results are
consistent that THC exacerbates psychosis. It doesn’t alleviate it,” study
authors said. In some people, they note, certain sativa-dominant strains of
cannabis may worsen anxiety. The authors also state that THC can harm sleep and
cause mood problems.
Medical marijuana advocate
Mitch Earleywine, a professor of psychology at State University of New York,
Albany, told USNews: “Unfortunately, I would guess that headlines
worldwide will claim directly or indirectly that cannabinoids are no help, but
in fact, we don’t know if they do or not.”