Cannabis for PTSD
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Visual Abstract
Summary
Cannabis for the Management of Symptoms of PTSD: A Living Systematic Review
Background
- Cannabis use in the US since 2002 has risen from 11% to almost 18% of the population as more states legalize cannabis for recreational and medicinal purposes.
- Numerous states approved cannabis for a wide range of medical purposes including posttraumatic stress disorder (PTSD).
- This is an update of a living systematic review first posted in March 2021 assessing the effectiveness of cannabis for PTSD.
Methods
Living systematic review
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Screening: Studies (controlled clinical trials and observational studies with comparison groups) assessed the effects of plant-based cannabis preparations; whole-plant extracts (e.g., nabiximols); or US Food and Drug Administration (FDA)-approved synthesized, pharmaceutically prepared cannabinoids (e.g., dronabinol, nabilone) in nonpregnant adults with PTSD
Risk of Bias (RoB): Scottish Intercollegiate Guidelines Network (SIGN) tool
GRADE:
- Overall certainty of evidence (CoE) for each outcome determined by using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach
Updates: Search to be updated every 6 months with new reports as needed
Findings
- 7 eligible studies (4 published in this update)
- 2 crossover randomized controlled trials (RCTs)
- 5 retrospective cohort studies
- One RCT (N = 80) rated as having low RoB and 5 cohort studies (moderate to high RoB; N range = 136 to 2,276) found no difference in PTSD symptoms with cannabis (low CoE)
- There was also no difference in mental health symptoms between cannabis and placebo groups from the same RCT (low CoE)
- It is uncertain whether cannabis affects other PTSD symptoms including nightmares, sleep quality, and functional status.
Summary of Findings (GRADE)
| Outcome Studies; Sample Size |
Certainty of the Evidence | Relationship | Rationale for CoE Rating |
| PTSD symptom severity 1 RCT; N = 80 5 cohort studies; N = 4,315 |
⨁⨁◯◯Low | No difference: cannabis was not associated with clinically significant improvement in symptom severity in the trial or cohort studies | Downgraded 1 level each for RoB and indirectness |
| PTSD-related nightmares 1 RCT; N = 10 |
⨁◯◯◯Very low | Nabilone significantly reduced frequency and intensity of recurring and distressing dreams | Downgraded 1 level each for RoB, imprecision, and indirectness |
| Sleep quality 2 RCTs; N = 90 1 cohort study; N = 150 |
⨁◯◯◯Very low | No difference: no difference in insomnia, or sleep quality or quantity with cannabinoids compared to placebo in RCTs and no association with any sleep quality measures in the cohort study | Downgraded 1 level each for RoB, imprecision, and indirectness |
| Functional status 2 RCTs; N = 90 1 cohort study; N = 150 |
⨁◯◯◯Very low | No difference: no difference in global functioning or psychosocial functioning in RCTs or cohort study | Downgraded 1 level each for RoB, imprecision, and indirectness |
| Mental health symptoms 1 RCT; N = 80 |
⨁⨁◯◯Low | No difference: smoked cannabis was no different than placebo for reduction in general depression or social anxiety | Downgraded 1 level each for imprecision and indirectness |
| Quality of life | Not applicable | — | — |
| Utilization of health services | Not applicable | — | — |
Abbreviations. CoE: Certainty of Evidence, GRADE: Grading of Recommendations Assessment, Development and Evaluation; PTSD: posttraumatic stress disorder; RCT: randomized controlled trial; ROB: risk of bias.
GRADE certainty of evidence: Very low ⨁◯◯◯; Low ⨁⨁◯◯; Moderate ⨁⨁⨁◯; High ⨁⨁⨁⨁
Conclusions
- There is low CoE that cannabis does not affect PTSD symptoms, general depression, or social anxiety.
- The evidence for cannabis and other PTSD-related outcomes remains uncertain after identifying and reviewing additional eligible studies in this update.
- The need for future research to evaluate the benefits and harms of cannabis becomes more critical as diagnoses of PTSD increase, particularly in the Veteran population.
Gaps in Evidence
- No evidence on cannabis’ effects on quality of life or health services utilization in people with PTSD.
- There is a need for high quality, randomized studies of cannabinoids to determine whether cannabis has any effects on PTSD symptoms.
- There are 8 ongoing trials assessing the effects of cannabis on various aspects of PTSD that should be completed over the next several years.
References
Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-926.
O’Neil ME, Nugent SM, Morasco BJ, et al. Benefits and harms of plant-based cannabis for posttraumatic stress disorder: a systematic review. Ann Intern Med. 2017;167(5):332-340.
Scottish Intercollegiate Guidelines Network. Methodology checklist 2: randomised controlled trials. https://www.sign.ac.uk/what-we-do/methodology/checklists/. Published 2015. Accessed October 30, 2020.
Scottish Intercollegiate Guidelines Network. Methodology checklist 3: cohort studies. https://www.sign.ac.uk/what-we-do/methodology/checklists/. Published 2014. Accessed October 30, 2020.
Substance Abuse and Mental Health Services Administration. Key Substance Use and Mental Health Indicators in the United States: Results from the 2019 National Survey on Drug Use and Health. https://www.samhsa.gov/data/sites/default/files/reports/rpt29393/2019NSDUHFFRPDFWHTML/2019NSDUHFFR090120.htm#illi2
Ayers C, Harrod C, Durbin S, Shaw B, Robalino S, Paynter R, Yeddala S, Kansagara D. Cannabis for the management of symptoms of PTSD: A living systematic review. Portland, OR: The Systematically Testing the Evidence on Marijuana Project. 2021; revised December 2022. https://www.cannabisevidence.org/evidence-syntheses/ptsd/
