Does Medical Cannabis Relieve Chronic Pain?

While there is convincing preclinical evidence suggesting the analgesic potential of cannabinoids, clinical data so far do not provide a definitive answer. Most trials are small, short-term, and methodologically limited, which significantly reduces their reliability.

Cannabinoids in the Body

Cannabis contains over one hundred cannabinoids that interact with the endocannabinoid system. The best known are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC activates CB1 receptors in the central nervous system, producing analgesic effects but also causing psychiatric side effects. CBD, in contrast, inhibits these receptors, is non-psychoactive, may mitigate THC’s effects, acts anti-inflammatory and antioxidative, and also modulates serotonin pathways.

Alongside these two, researchers are also studying so-called minor cannabinoids such as cannabigerol, cannabichromene, and cannabinol, which act on multiple pain-related receptors. The therapeutic effect of cannabis-based preparations depends on the THC-to-CBD ratio: higher THC content may be more effective in pain relief but carries psychiatric risks, whereas CBD may be more suitable for inflammatory conditions and is generally better tolerated.

Knowledge Still Limited

In 2021, the International Association for the Study of Pain convened a panel of 20 experts to systematically evaluate the evidence. Their conclusions were cautious: knowledge is limited and study quality insufficient. Reviews published the same year also produced mixed findings: some confirmed mild reductions in pain compared to placebo, while others highlighted frequent adverse effects such as dizziness, drowsiness, nausea, or cognitive impairment.

The landscape is evolving. Reviews from 2024 indicate that cannabinoids may serve as an alternative or adjunct to opioids, potentially reducing opioid use. Randomized studies published in Biomedicines provided moderate evidence of cannabinoid efficacy in neuropathic pain and multiple sclerosis symptom management. Weaker but intriguing signals have been reported in migraine, fibromyalgia, and musculoskeletal pain.

Fragmented European Legislation

European cannabis legislation is changing dynamically. Italy requires special prescription forms, the UK has approved two cannabis-based medicines, and Germany’s legalization of recreational use in 2024 has also facilitated medical access. France, Spain, Denmark, and Slovenia are gradually expanding their programs, while the Netherlands plans to end its state monopoly.

According to the European Cannabis Report, nearly half a million Europeans legally used cannabis by the end of 2024. Despite the European Parliament’s 2019 call for harmonized rules and more research support, regulations remain fragmented.

Risks versus Benefits

Main risks include tolerance, dependence from long-term THC use, anxiety, psychosis, and drug interactions. Still, some patients consider cannabis safer than opioids, reporting improved quality of life even when pain intensity itself does not change.

Authors of a study in the Journal of Cannabis Research even speculate that psychoactive effects may not be purely detrimental, but part of the therapeutic benefit—through improved mood and emotional state.

An as-yet unpublished study from the University of Colorado compared the acute effects of vaporized cannabis (THC-dominant with minimal CBD) to placebo in patients with chronic back pain. Cannabis provided significantly more relief than placebo.

Methodological Challenges

Although cannabis has been used in medicine for millennia, modern research was long hindered by its classification as a narcotic. Clinical studies today still face regulatory barriers and methodological challenges.

Cannabis is not a uniform substance—there are many forms, from oils and dried flowers to edibles. Cannabinoid content varies by cultivation and batch, complicating standardization and comparability. As researchers note, “It’s not like having one pill in two doses. It’s much more complex.”

Pain itself also presents a methodological challenge—it is a subjective sensation with diverse causes, and patients respond differently. Finding a homogeneous study population is difficult.

Cannabis in Clinical Practice

Current data suggest that medical cannabis may relieve pain in some patients, especially neuropathic pain, and help reduce opioid use. However, benefits must be weighed against risks, and therapy always tailored individually. A clear answer does not yet exist, and more standardized research is necessary.

Physicians should create an environment where patients feel comfortable discussing cannabis use openly. The treatment goal should not only be a numeric reduction in pain but also improved function and quality of life—such as better sleep, work ability, or social engagement. If a patient uses high doses of cannabis yet remains functionally impaired, the real therapeutic value should be reconsidered.

Editorial Team, Medscope.pro

Sources:

1. Longo R., Oudshoorn A., Befus D. Cannabis for chronic pain: a rapid systematic review of randomized control trials. Pain Management Nursing 2021; 22 (2): 141–149. doi: 10.1016/j.pmn.2020.11.006.
2. Wang L., Hong P. J., May C. et al. Medical cannabis or cannabinoids for chronic non-cancer and cancer related pain: a systematic review and meta-analysis of randomised clinical trials. BMJ 2021; 374:n1034. doi: 10.1136/bmj.n1034.
3. Jylkkä J., Hupli A., Nikolaeva A. et al. The holistic effects of medical cannabis compared to opioids on pain experience in Finnish patients with chronic pain. J Cannabis Res 2023; 5 (1): 38. doi: 10.1186/s42238-023-00207-7.
4. Cortez-Resendiz A., Leiter T. J., Riela S. M. et al. The Pharmacology of Cannabinoids in Chronic Pain. Med Cannabis Cannabinoids 2025; 8 : 31–46. doi: 10.1159/000543813.
5. Johnson B. W., Strand N. H., Raynak J. C. et al. Cannabinoids in Chronic Pain Management: A Review of the History, Efficacy, Applications, and Risks. Biomedicines 2025; 13 (3): 530. doi: 10.3390/biomedicines13030530.