Which Cannabinoid Works for What? The Definitive Review of 152 Trials
What Researchers Found About Epilepsy and Cannabis
The Study at a Glance
Published
BMC Medicine, 2022
Researchers
Multiple institutions (International)
Study Type
Systematic ReviewParticipants
12,123 patients · Varies by trial
Key Finding
Cannabinoids are effective therapeutics for several medical indications if their specific pharmacological properties are considered. Different cannabinoids have different evidence levels for different conditions.
Key Finding: Cannabinoids are effective therapeutics for several medical indications if their specific pharmacological properties are considered. Different cannabinoids have different evidence levels for different conditions.
What Researchers Studied About Epilepsy and Cannabis
Different cannabinoids (CBD, THC, dronabinol, nabilone, nabiximols) have different pharmacological properties and may have different treatment effects. This review examined how well each specific cannabinoid works for each specific condition.
Researchers analyzed 152 randomized controlled trials with 12,123 total participants across 22 medical conditions.
The conditions studied included chronic pain, spasticity, nausea/vomiting, appetite, ALS, irritable bowel syndrome, multiple sclerosis, Huntington's disease, epilepsy, Parkinsonism, glaucoma, ADHD, anxiety, depression, schizophrenia, PTSD, sleep disorders, substance use disorders, and Tourette syndrome.
How This Systematic Review Was Conducted
Researchers searched 8 databases for randomized controlled trials of dronabinol, nabilone, cannabidiol, and nabiximols.
Outcomes were calculated as standardized mean differences (SMD) with confidence intervals. Evidence quality was assessed using Cochrane Risk of Bias and GRADE tools.
The 152 RCTs resulted in 84 different comparisons across cannabinoid types, conditions, and outcomes.
Epilepsy Treatment Results
The Main Results:
- 1CBD for epilepsy: HIGH-grade evidence (SMD -0.50, 95% CI -0.62 to -0.38)
- 2CBD for Parkinsonism: MODERATE-grade evidence (SMD -0.41, 95% CI -0.75 to -0.08)
- 3Dronabinol for chronic pain: MODERATE-grade evidence (SMD -0.31)
- 4Dronabinol for appetite: MODERATE-grade evidence (SMD -0.51)
- 5Dronabinol for Tourette: MODERATE-grade evidence (SMD -1.01)
- 6Nabiximols for chronic pain: MODERATE-grade evidence (SMD -0.25)
- 7Nabiximols for spasticity: MODERATE-grade evidence (SMD -0.36)
- 8Nabiximols for sleep: MODERATE-grade evidence (SMD -0.24)
- 9All other conditions have LOW, VERY LOW, or NO grade of evidence
By the Numbers
| Statistic | What It Means |
|---|---|
| 152 RCTs | Total randomized controlled trials analyzed (12,123 participants) |
| HIGH grade | Only CBD for epilepsy achieved the highest evidence quality rating |
| 84 comparisons | Different cannabinoid-condition-outcome combinations analyzed |
| -1.01 SMD | Largest effect size was dronabinol for Tourette syndrome (moderate evidence) |
Total randomized controlled trials analyzed (12,123 participants)
Only CBD for epilepsy achieved the highest evidence quality rating
Different cannabinoid-condition-outcome combinations analyzed
Largest effect size was dronabinol for Tourette syndrome (moderate evidence)
What This Means for Epilepsy Patients
This comprehensive review shows that cannabinoid effectiveness depends heavily on WHICH cannabinoid you use for WHICH condition.
The strongest evidence (high-grade) exists only for CBD treating epilepsy. Moderate evidence supports: - CBD for Parkinson's symptoms - Dronabinol for chronic pain, appetite, and Tourette syndrome - Nabiximols for chronic pain, spasticity, and sleep
For many other conditions (anxiety, depression, PTSD, etc.), the evidence is low quality or absent. This means claims about cannabis helping these conditions are not well-supported by rigorous research.
When considering medical cannabis, ask your doctor specifically which cannabinoid product has evidence for your specific condition.
Quick Answers: Epilepsy 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.
What conditions does medical cannabis actually help?
High-grade evidence only for CBD in epilepsy. A 2022 review of 152 trials found MODERATE evidence supports dronabinol for Tourette/appetite/pain, nabiximols for spasticity/pain/sleep, and CBD for Parkinsonism. Most other conditions have weak evidence.
Source: Bilbao & Spanagel, BMC Medicine, 2022 (PMID: 35982439)
Which is better, CBD or THC?
It depends on the condition. CBD has high-grade evidence for epilepsy. THC-containing products (dronabinol, nabiximols) have moderate evidence for Tourette, spasticity, appetite, and chronic pain. Neither is universally "better."
Source: Bilbao & Spanagel, BMC Medicine, 2022 (PMID: 35982439)
Is there good evidence for medical marijuana?
Yes, for some conditions. A review of 152 trials found high-grade evidence for CBD in epilepsy, and moderate evidence for Tourette, Parkinsonism, spasticity, chronic pain, appetite, and sleep. Evidence for other conditions is weak.
Source: Bilbao & Spanagel, BMC Medicine, 2022 (PMID: 35982439)
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:
- Evidence quality varies dramatically by cannabinoid and condition
- Most conditions have only low or very low quality evidence
- Adverse events vary by cannabinoid type
- Long-term effects not well studied in most trials
- Many conditions have insufficient data for firm conclusions
The Bottom Line on Cannabis for Epilepsy
This definitive review of 152 trials shows cannabinoid effectiveness depends on matching the right cannabinoid to the right condition. Only CBD for epilepsy has high-grade evidence. Moderate evidence supports dronabinol for Tourette/appetite/pain, nabiximols for spasticity/pain/sleep, and CBD for Parkinson symptoms. For most other conditions, evidence is weak or absent. Patients should ask specifically which cannabinoid has evidence for their condition.
Do You Qualify for Medical Marijuana?
If you're living with Epilepsy, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
Get Your Card
This condition qualifies for medical marijuana in:
Source
Bilbao A, Spanagel R "Medical cannabinoids: a pharmacology-based systematic review and meta-analysis for all relevant medical indications" BMC Medicine. 2022. DOI: 10.1186/s12916-022-02459-1
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 Epilepsy
Which cannabinoid has the strongest evidence?
CBD for epilepsy has the only HIGH-grade evidence (SMD -0.50). Moderate evidence exists for dronabinol (Tourette, appetite, pain), nabiximols (spasticity, pain, sleep), and CBD (Parkinsonism).
Does cannabis help anxiety and depression?
No, evidence is low quality. According to this 152-trial review, evidence for cannabinoids in anxiety and depression is LOW or VERY LOW quality. High-grade evidence exists only for CBD in epilepsy.
Do all cannabinoids work the same?
No. This review found that different cannabinoids (CBD, THC, dronabinol, nabilone, nabiximols) have different evidence levels for different conditions. Matching the right cannabinoid to the right condition is essential.