The Long-Term, Prospective, Therapeutic Impact of Cannabis on Post-Traumatic Stress Disorder

<b>Introduction:</b> Given the increasing availability and use of cannabis among individuals with post-traumatic stress disorder (PTSD) and the addition of PTSD as an eligible diagnosis in several U.S. medical cannabis programs, the efficacy of dispensary-obtained cannabis needs to be thoroughly examined. <b>Materials and Methods:</b> This prospective study assessed PTSD symptoms and functioning every 3 months over the course of a year in two samples of participants diagnosed with PTSD: (1) those with PTSD using dispensary-obtained cannabis (cannabis users) and (2) those with PTSD, who do not use cannabis (controls). Linear mixed-effects models and generalized estimating equations tested whether trajectories of symptoms differed between the two subsamples. <b>Results:</b> A total of 150 participants (mean [standard deviation] age, 50.67 [15.26] years; 73% male) were enrolled in the study. Over the course of 1 year, the cannabis users reported a greater decrease in PTSD symptom severity over time compared to controls [group×time interaction=-0.32 (95% confidence interval [CI]=-0.59 to -0.05, <i>R</i>²=0.13; <i>t</i>=-2.35, <i>p</i>=0.02). Participants who used cannabis were 2.57 times more likely to no longer meet DSM-5 criteria for PTSD at the end of the study observation period compared to participants who did not use cannabis (95% CI=1.12-6.07; <i>p</i>=0.03). <b>Conclusions:</b> This study provides evidence that the types of cannabis available in recreational and medical cannabis dispensaries might hold promise as an alternative treatment for PTSD. Randomized placebo-controlled trials are needed to assess safety and determine how different preparations of cannabis impact PTSD and functioning.