The research, conducted at Washington State University, analyzed self-reported data from more than 400 PTSD patients before and after they smoked or vaped marijuana, collecting more than 11,000 patient entries over 31 months. (Although other forms of marijuana use, such as oral ingestion, were also monitored, that data wasn't included in the published study.)
Flashbacks to trauma were reduced by over 50 percent on average among participants, the study shows, with anxiety falling 57 percent and intrusive thoughts and irritability dropping 62 and 67 percent, respectively. However, the reductions weren't permanent, the authors say.
According to WSU assistant psychology professor and lead researcher Carrie Cuttler, marijuana use appeared to be a "band aid" for PTSD that can "temporarily mask symptoms."
"While inhaled cannabis resulted in significant and substantial reductions in ratings of all four of the PTSD symptoms that we assessed, it is important to note that we detected significant heterogeneity in these effects across individuals, indicating that cannabis may not uniformly reduce PTSD symptoms for everyone," the study reads.
Although medical marijuana is widely used for self-medication among PTSD patients in the 28 states that have legalized it, the limited number of published studies analyzing marijuana's effects on PTSD have been conducted on a very small scale. For instance, the WSU study, like the majority of recent university research concerning marijuana, had to rely on patients' self-reported data because of the plant's federal prohibition. Federal restrictions also restricted WSU researchers from studying a control group using placebo medication, the authors note.
The research phase of the first federally approved study of PTSD and marijuana, led by Dr. Sue Sisley at the Scottsdale Research Institute, concluded in 2019. Sisley's team actually distributed the marijuana used by study participants during the research, and results are expected to be published later this year.
Colorado lawmakers approved PTSD as a medical marijuana condition in 2017, a move opposed for years by the state Board of Health as well as the Colorado Department of Public Health and Environment, both of which cited a lack of research. When it became apparent that patients with other diagnoses were using it for PTSD, however, the CDPHE supported adding it to the list of approved conditions in order to collect data on PTSD patients using medical marijuana. As of March, nearly 13 percent of Colorado's 81,722 medical marijuana patients reported PTSD as one of their conditions, according to the CDPHE.