Cannabis for PTSD
Cannabis for the Management of Symptoms of PTSD: A Living Systematic Review
- 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.
Living systematic review
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
- 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
- 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)
|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|
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|
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|
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 ⨁⨁⨁⨁
- 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.
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; December 2021. https://www.cannabisevidence.org/evidence-syntheses/ptsd/