The Effectiveness of Cannabinoids in the Treatment of Posttraumatic Stress Disorder (PTSD): A Systematic Review

Abstract

Objectives: Posttraumatic stress disorder (PTSD) is a potentially debilitating mental health problem. There has been a recent surge of interest regarding the use of cannabinoids in the treatment of PTSD. We therefore sought to systematically review and assess the quality of the clinical evidence of the effectiveness of cannabinoids for the treatment of PTSD. Method: We included all studies published until December 2018 where a patient has had PTSD diagnosed and had been prescribed or were using a cannabinoid for the purpose of reducing PTSD symptoms. Our primary outcome measure was the reduction in PTSD symptoms using a validated instrument. In the absence of randomized controlled trials, we included the next best available levels of evidence including observational and retrospective studies and case reports. We assessed risk of bias and quality using validated tools appropriate for the study design. Results: We included 10 studies in this review, of which only one study was a pilot randomized, double-blind, placebo-controlled, crossover clinical trial. Every identified study had medium to high risk of bias and was of low quality. We found that cannabinoids may decrease PTSD symptomology, in particular sleep disturbances and nightmares. Conclusions: Most studies to date are small and of low quality, with significant limitations to the study designs precluding any clinical recommendations about its use in routine clinical practice. Evidence that cannabinoids may help reduce global PTSD symptoms, sleep disturbances, and nightmares indicates that future well-controlled, randomized, double-blind clinical trials are highly warranted.

PROSPERO registration number: 121646

Keywords:

• Cannabis
• THC
• CBD
• nabilone
• posttraumatic stress disorder
• treatments

Acknowledgments

We are grateful to our funders.

Disclosure statement

The authors have no conflicts of interest.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Dr. Bloomfield is funded by a UCL Excellence Fellowship. Drs. Hindocha and Bloomfield are supported by the National Institute of Health Research University College London Hospitals Biomedical Research Center. This study was supported by the NIHR University College London Hospitals Biomedical Research Center. Dr. Cousijn is funded by NIH-NIDA (R01 DA042490-01A1) and Amsterdam Brain and Cognition.