An updated systematic review provides clarity on the efficacy and safety of cannabinoids for chronic pain treatment. The comprehensive review analyzed 25 short-term, placebo-controlled randomised trials. Furthermore, the studies focused primarily on neuropathic pain. Clinicians must, therefore, understand the critical distinction in therapeutic effect and adverse events based on the ratio of Tetrahydrocannabinol (THC) to Cannabidiol (CBD). Ultimately, the findings suggest that not all cannabis-based products deliver the same results.
The Role of THC Ratio in Pain Reduction
The systematic review categorised cannabinoid products based on their THC-to-CBD ratio: high, comparable, or low. High THC-to-CBD ratio products, specifically oral synthetic/purified THC-only products, resulted in a small reduction in pain severity. The pooled difference was -0.78 points on a 0-to-10 scale. Additionally, oromucosal, extracted products with a comparable THC-to-CBD ratio probably delivered a slightly smaller pain reduction (-0.54 points). The study compared high-ratio THC-only products: nabilone moderately reduced pain severity by -1.59 points. Conversely, the other studied THC-only product, dronabinol, showed no meaningful benefit, with a pooled difference of only -0.23 points.
Implications of Cannabinoids for Chronic Pain in India
The current findings highlight the complexity of utilizing cannabinoids for chronic pain management. While high-THC products showed modest, short-term benefits, they come with notable side effects like dizziness, sedation, and nausea. In India, the use of cannabis for medical purposes operates in a legal gray area, though traditional systems like Ayurveda have long incorporated it. The Central Government, however, has clarified that the law permits cannabis use for medical and scientific purposes. Major research bodies, including the ICMR and CSIR, have also shown interest in the clinical development of cannabis phytopharmaceuticals for conditions like chronic pain. This updated systematic review therefore provides timely, evidence-based data for clinicians navigating the evolving therapeutic landscape.
Frequently Asked Questions
Q1: Which specific high-THC product showed the most significant pain reduction?
Among the THC-only products studied, the cannabinoid nabilone demonstrated a moderate reduction in pain severity, with a pooled difference of -1.59 points on the 0-to-10 scale. Dronabinol, another high-THC product, did not show a comparable effect.
Q2: What common adverse events are associated with high-THC ratio products?
High and comparable THC-to-CBD ratio products were consistently associated with moderate or large increases in common adverse events, including dizziness, sedation, and nausea.
Q3: Did products with a low THC-to-CBD ratio, including CBD alone, prove effective for chronic pain?
No. The review found that low THC-to-CBD ratio products and CBD-only formulations may not improve patient outcomes or reduce chronic pain.
References
- Chou R et al. Cannabis-Based Products for Chronic Pain : An Updated Systematic Review. Ann Intern Med. 2025 Dec 23. doi: 10.7326/ANNALS-25-03152. PMID: 41429020.
- Anson, P. Review Finds THC More Effective Than CBD for Chronic Pain. Pain News Network. Published 2025 Dec 23.
- Chou, R et al. Cannabis-Based Products for Chronic Pain : An Updated Systematic Review. SciTechDaily. Published 2025 Dec 22.
- India Hemp Organics. Is the Use of Cannabis for Medical Purposes Permitted in India? [Internet]. Available from: [Accessed Dec 2025].
- Sharma, M. et al. Clinical studies with Cannabis in India – A need for guidelines for the investigators and ethics committees. Perspect Clin Res. 2020;11(4):165–170.