First PTSD Cannabis Trial: No Treatment Outperformed Placebo
What Researchers Found About Ptsd and Cannabis
The Study at a Glance
Published
PLoS One, 2021
Researchers
Multiple institutions (USA)
Study Type
Randomized Controlled TrialParticipants
80 patients · 3 weeks per stage (crossover)
Key Finding
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.
Key Finding: 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.
What Researchers Studied About Ptsd and Cannabis
Cannabis use is increasing among US military veterans to self-treat PTSD. This was the first randomized placebo-controlled trial of smoked cannabis for PTSD.
The study tested three different cannabis formulations against placebo in veterans with PTSD.
This addresses a pressing need for novel pharmacology for PTSD treatment.
How This Randomized Controlled Trial Was Conducted
Double-blind, cross-over design with 80 participants randomized in Stage 1 and 74 completing Stage 2.
Three active cannabis concentrations tested: - High THC: approximately 12% THC and less than 0.05% CBD - High CBD: 11% CBD and 0.50% THC - THC+CBD: approximately 7.9% THC and 8.1% CBD - Placebo: less than 0.03% THC and less than 0.01% CBD
Participants received 3 weeks in Stage 1, then re-randomized after 2-week washout to one of the other treatments in Stage 2.
Ptsd Treatment Results
The Main Results:
- 1Primary outcome: NO significant difference in PTSD symptom severity between active cannabis and placebo
- 2All three active concentrations were generally well tolerated
- 3ALL groups (including placebo) showed significant improvements in PTSD symptoms
- 4No active treatment statistically outperformed placebo
- 5This is the FIRST randomized placebo-controlled trial of smoked cannabis for PTSD
By the Numbers
| Statistic | What It Means |
|---|---|
| 80 patients | US military veterans with PTSD randomized in Stage 1 |
| No difference | No significant difference between any cannabis formulation and placebo |
| 3 formulations | High THC, High CBD, and THC+CBD all tested against placebo |
| All improved | All groups including placebo showed significant PTSD symptom improvement |
US military veterans with PTSD randomized in Stage 1
No significant difference between any cannabis formulation and placebo
High THC, High CBD, and THC+CBD all tested against placebo
All groups including placebo showed significant PTSD symptom improvement
What This Means for Ptsd Patients
If you are a veteran considering cannabis for PTSD, this trial provides important findings.
This was the first rigorous, placebo-controlled trial of smoked cannabis for PTSD. Disappointingly, none of the three cannabis formulations (high THC, high CBD, or THC+CBD) performed better than placebo.
All groups, including placebo, showed significant improvements in PTSD symptoms over 3 weeks. This suggests that factors other than the cannabis itself (such as participation in a clinical trial, regular monitoring, or expectation effects) may be responsible for improvement.
The cannabis was well tolerated, so it was not harmful. But it also was not more effective than placebo in this study.
The researchers note this was a "brief, preliminary trial" and call for additional well-controlled studies. If you are using cannabis for PTSD, discuss these findings with your mental health provider.
Quick Answers: Ptsd and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
Does marijuana help with PTSD?
No, no formulation outperformed placebo. The first placebo-controlled trial (80 veterans) found high-THC, high-CBD, and THC+CBD all failed to show significant benefit over placebo. All groups improved equally.
Source: Bonn-Miller et al., PLoS One, 2021 (PMID: 33730032)
What does research say about cannabis for PTSD?
No cannabis preparation beat placebo. The first randomized placebo-controlled trial found all groups improved, suggesting non-specific factors (not cannabis) may explain improvement. More research is needed.
Source: Bonn-Miller et al., PLoS One, 2021 (PMID: 33730032)
Is THC or CBD better for PTSD?
Neither. A 2021 trial tested high-THC, high-CBD, and balanced THC+CBD against placebo in veterans. None outperformed placebo for PTSD symptoms. All were well tolerated but not more effective than placebo.
Source: Bonn-Miller et al., PLoS One, 2021 (PMID: 33730032)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Brief duration (3 weeks per stage)
- Strong placebo response may have masked effects
- Preliminary study design
- Need for larger, longer-term studies
- Cannabis formulations may not be optimal for FDA drug development
The Bottom Line on Cannabis for Ptsd
This first placebo-controlled trial of smoked cannabis for PTSD in 80 veterans found NO cannabis formulation outperformed placebo. All groups (including placebo) improved significantly, suggesting factors other than cannabis may explain symptom improvement. Cannabis was well tolerated but not more effective than placebo. Additional well-controlled studies are needed.
Do You Qualify for Medical Marijuana?
If you're living with Ptsd, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
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- Can Cannabis Treat Mental Health Conditions? The Evidence
- Medical Cannabis for Chronic Pain: A Practical Review
- Clinical Practice Guidelines: Cannabis for Chronic Pain & Co-Occurring Conditions (2024)
- The Endocannabinoid System: Why Cannabis Works
- Medical Cannabis for Cancer Patients: Real-World Results
Condition Research
Get Your Card
This condition qualifies for medical marijuana in:
Source
Bonn-Miller MO, Sisley S, Riggs P, et al. "The short-term impact of 3 smoked cannabis preparations versus placebo on PTSD symptoms: A randomized cross-over clinical trial" PLoS One. 2021. DOI: 10.1371/journal.pone.0246990
Important Information
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 25, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
Copyright & Fair Use
Research summaries are provided under fair use (17 U.S.C. § 107) for educational purposes. We provide brief summaries with attribution, not full reproductions. All studies remain the intellectual property of their respective authors and publishers.
Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
For complete information, see our Terms of Use and Research Content Policy.
FAQs: Cannabis for Ptsd
Does cannabis help PTSD?
No, cannabis did not outperform placebo. In the first placebo-controlled trial (80 veterans), no cannabis formulation outperformed placebo for PTSD symptoms. All groups improved equally.
What type of cannabis is best for PTSD?
None outperformed placebo. High-THC, high-CBD, and THC+CBD formulations were tested. The researchers concluded "no active treatment statistically outperformed placebo in this brief, preliminary trial."
Is cannabis safe for veterans with PTSD?
Safe but not more effective than placebo. All three active cannabis concentrations were "generally well tolerated" but not more effective than placebo for reducing PTSD symptoms.