The short-term impact of 3 smoked cannabis preparations versus placebo on PTSD symptoms: A randomized cross-over clinical trial

Abstract

Importance: There is a pressing need for development of novel pharmacology for the treatment of Posttraumatic Stress Disorder (PTSD). Given increasing use of medical cannabis among US military veterans to self-treat PTSD, there is strong public interest in whether cannabis may be a safe and effective treatment for PTSD.

Objective: The aim of the present study was to collect preliminary data on the safety and potential efficacy of three active concentrations of smoked cannabis (i.e., High THC = approximately 12% THC and < 0.05% CBD; High CBD = 11% CBD and 0.50% THC; THC+CBD = approximately 7.9% THC and 8.1% CBD, and placebo = < 0.03% THC and < 0.01% CBD) compared to placebo in the treatment of PTSD among military veterans.

Methods: The study used a double-blind, cross-over design, where participants were randomly assigned to receive three weeks of either active treatment or placebo in Stage 1 (N = 80), and then were re-randomized after a 2-week washout period to receive one of the other three active treatments in Stage 2 (N = 74). The primary outcome measure was change in PTSD symptom severity from baseline to end of treatment in Stage 1.

Results: The study did not find a significant difference in change in PTSD symptom severity between the active cannabis concentrations and placebo by the end of Stage 1. All three active concentrations of smoked cannabis were generally well tolerated.

Conclusions and relevance: The present study is the first randomized placebo-controlled trial of smoked cannabis for PTSD. All treatment groups, including placebo, showed good tolerability and significant improvements in PTSD symptoms during three weeks of treatment, but no active treatment statistically outperformed placebo in this brief, preliminary trial. Additional well-controlled and adequately powered studies with cannabis suitable for FDA drug development are needed to determine whether smoked cannabis improves symptoms of PTSD.

Trial registration: Identifier: NCT02759185; ClinicalTrials.gov.

Conflict of interest statement

Author MBM is an employee of Canopy Growth Corporation, during which time he has received stock options, serves on the Board of Directors for AusCann Group Holdings Limited, was a prior employee of Zynerba Pharmaceuticals, and has received consulting fees from Tilray Inc. Author ML serves on the scientific advisory board for FSD Pharma and has received consulting fees from Greenwich Biosciences, Zynerba Pharmaceuticals, and Tilray Inc in the past two years. Authors RD, BY, JW, BS, CH, RM, and AE receive salary from the Multidisciplinary Association for Psychedelic Studies (MAPS), a 501(c)(3) non-profit research and educational organization. Author SS receives salary from the Scottsdale Research Institute, which is a private LLC and has no shareholders. The Academic Editor, BLF, co-authored "The state of clinical outcome assessments for cannabis use disorder clinical trials: A review and research agenda" (https://pubmed.ncbi.nlm.nih.gov/32360455/) with one of the authors, MBM. This article was a result of a meeting where a large number of investigators came together to discuss clinical trial outcomes with representative from NIH and FDA. No other relationship between this author and the Academic Editor exists. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1. Consort flow diagram.

Fig 2. Mean total marijuana withdrawal scores by treatment condition across Stage 1 & Stage 2.

Fig 3. Post hoc Mixed Models for Repeated Measures (MMRM) testing change in PCL-5, IDAS depression, IDAS anxiety, and ISI scores over time.