The study, published last month in the Journal of Psychoactive Drugs, compared PTSD scores of 80 patients in New Mexico’s medical marijuana program before and after they began using cannabis. The results showed an average drop in disease scores of over 75%.
All patients in the study had applied to participate in the state’s medical marijuana program between 2009-2011. In 2009, New Mexico became the first state to list post-traumatic stress disorder as a qualifying condition for medical marijuana. Despite a lack of clinical data, similar laws now exist in seven other states.
“Cannabis is associated with PTSD symptom reduction”Likewise, since the study was not conducted in a clinical setting and only looked at patients who reported benefits from cannabis use, the latest findings carry minimal weight.
The authors say large-scale trials are needed before a firm conclusion can be drawn.
“Though currently there is no substantial proof of the efficacy of cannabis in PTSD treatment, the data reviewed here supports a conclusion that cannabis is associated with PTSD symptom reduction in some patients,” writes George Greer, MD, who runs a private practice in New Mexico.
“A prospective, placebo-controlled study of cannabis or its constituents for treatment of PTSD is warranted,” he adds.
The study was co-authored by psychiatry specialists Charles Grob, MD of Harbor-UCLA Medical Center and Adam Halberstadt, PhD of University of California San Diego.
Despite drawbacks to the study’s design, the authors say previous research lends support to their findings. Specifically, a small Israeli study involving 29 combat veterans with PTSD found a 50% reduction in disease scores after 4 to 11 months of medical marijuana treatment.
“It has also been reported that the synthetic cannabinoid nabilone can reduce the incidence and severity of nightmares in PTSD patients,” note the authors.
A number of animal studies provide “extensive evidence that cannabinoids may facilitate extinction of aversive memories” as well.
The United States Department of National Defence and the U.S. National Institute of Mental Health is currently funding a three-year project, led by a team at NYU, to develop a drug for PTSD that mimics the effects of marijuana.
Earlier this year, a group at Arizona State University also received approval from NIDA to conduct a clinical trial on smoked marijuana for treating PTSD.