Pilot Study of the Safety and Efficacy of Four Different Potencies of Smoked Marijuana in 76 Veterans With PTSD

PTSD is a serious, worldwide public health problem resulting from traumatic experiences such as sexual assault, war, or abuse. PTSD is associated with high rates of psychiatric and medical co-morbidity, disability, suffering, and suicide. Despite available treatments for PTSD, many individuals continue to experience marked PTSD symptoms following treatment. In response to overwhelming demand for new treatments, several U.S. states have passed laws allowing the medical use of cannabis by individuals with PTSD. Emerging observational and early clinical evidence suggest that cannabis may have the potential to reduce or ameliorate a number of symptoms experienced by those with PTSD, including sleep difficulty and anxiety. Indeed, some evidence has suggested that delta-9-tetrahydrocannabinol (THC) may serve to reduce nightmares among those with PTSD, while other studies have shown anxiolytic effects of cannabidiol (CBD). However, there have been no randomized controlled trials of cannabis, in any form, for PTSD. The present triple-blind, randomized, placebo-controlled crossover trial aims to examine the safety and efficacy of four types of cannabis (i.e., high THC, low CBD; high CBD, low THC; equal ratio THC/CBD; and placebo) among 76 military veterans with chronic treatment-resistant PTSD of at least six months' duration. The study will produce preliminary evidence to help elucidate the contribution of THC, CBD, or a combination of both constituents to potential attenuation of PTSD symptoms. Smoked cannabis was tested in two stages lasting three weeks each (Stage 1 and Stage 2), with a two-week cessation after each stage, verified by blood/urine cannabinoid analysis. The primary objective was to compare three active concentrations of smoked cannabis and placebo on PTSD symptom severity measured by CAPS-5 total scores during Stage 1. Study participants received one of four different types of cannabis during Stage 1 with crossover and re-randomization, less the placebo cannabis, at Stage 2. The four potencies of cannabis were High THC/ Low CBD (High THC), Low THC/High CBD (High CBD), High THC/High CBD (THC/CBD) and Low THC/Low CBD (placebo). "High" is defined as marijuana containing a target of 7-15% concentration by weight of the respective cannabinoid and "Low" is defined as \< 2% concentration by weight. Prior to each stage, participants completed two introductory sessions where they were trained on cannabis self-administration. During each stage, participants were provided 1.8 grams of cannabis daily to smoke ad libitum. Each stage was followed by a two-week cessation period. The primary objective was to compare three active concentrations of smoked cannabis and placebo on PTSD symptom severity measured by CAPS-5 total severity scores during Stage 1.