Medical Cannabis: Effective For Chronic Pain, But Hard to Sustain Long-Term

Researchers have found that nearly 60% of patients using medical cannabis to treat chronic musculoskeletal pain discontinue treatment within a year. Despite its proven benefits in pain relief, factors such as advanced age, side effects, and personal expectations appear to influence continued use. The study reinforces the need to better understand how to adapt medical cannabis to different patient profiles.

Chronic musculoskeletal pain is an extremely common health problem affecting millions of people worldwide and can drastically reduce quality of life. It manifests when bones, muscles, joints, or tendons ache continuously for months or years, even after treatment for an injury or illness.

Despite the existence of various types of medications and physical therapies, many people continue to experience intense and debilitating pain, which has stimulated the search for alternative treatments, including the use of medical cannabis.

Medical cannabis refers to the controlled and supervised use of compounds derived from the Cannabis sativa plant, especially tetrahydrocannabinol (THC) and cannabidiol (CBD), for therapeutic purposes. These compounds act on the endocannabinoid system of the human body, a set of receptors and molecules that helps regulate functions such as pain, mood, and sleep.

THC, for example, binds primarily to CB1 receptors, located in the brain, helping to reduce the transmission of pain signals. CBD, on the other hand, acts on CB2 receptors, found in peripheral nerves and immune system cells, modulating the inflammatory response. Together, these effects explain why cannabis has been studied as a possible tool for relieving persistent pain.

Several clinical studies have already shown that medicinal cannabis can significantly reduce chronic pain in many patients, achieving results with over 50% improvement compared to placebo treatments. However, the benefits come with some important concerns.

Prolonged cannabis use can affect cognitive function, that is, the mental abilities responsible for memory, attention, and speed of reasoning. Research using brain imaging suggests that frequent and prolonged use can lead to a reduction in the volume of the hippocampus, a region essential for memory. Therefore, although effective for pain relief, its mental impact is still a cause for caution.

Furthermore, clinical experience shows that not all patients respond the same way to medicinal cannabis. While some report significant improvement, others abandon treatment due to dissatisfaction, lack of effectiveness, side effects, or preference for more traditional methods such as physiotherapy, injections, or surgery.

There is still little research on the reasons why people discontinue the use of medicinal cannabis, which is essential to understanding how it can be used more effectively and safely.

To investigate this issue, researchers conducted a retrospective study with 78 patients who used medicinal cannabis for up to two years to treat chronic musculoskeletal pain. They analyzed data such as age, type of pain, and general health status (physical and mental), measured before starting treatment. The research followed patients for a period of three months and then one year, evaluating who continued or discontinued use.

The results showed that 57.9% of patients discontinued the use of medicinal cannabis after one year, with almost half (44.7%) doing so within the first three months. Interestingly, older patients were the most likely to discontinue treatment.

The type of pain (e.g., lower back pain, osteoarthritis, fibromyalgia) did not show significant differences between those who continued and those who stopped use, nor was there any relevant variation in physical and mental health indices between the groups.

These findings suggest that the decision to discontinue medical cannabis use depends not only on the location of the pain or overall health status, but possibly on other factors such as personal expectations, perceived side effects, treatment cost, or even cultural issues.

The researchers conclude that further long-term investigations are needed to understand why many patients discontinue use and how to adjust treatment to make it more effective and sustainable.

READ MORE:

Discontinuation rates and predictors of Medical Cannabis cessation for chronic musculoskeletal pain

Mohammad Khak, Sina Ramtin, Juliet Chung, Asif M. Ilyas and Ari Greis,

PLoS One 20(8): e0329897

DOI: 10.1371/journal.pone.0329897

Abstract:

Medical cannabis (MC) is increasingly used as a treatment for chronic musculoskeletal pain, but there is limited data on factors influencing its discontinuation. This study aims to investigate the rates of MC discontinuation and explore factors influencing it in patients with chronic musculoskeletal pain. A retrospective analysis was conducted on 78 patients certified for medical cannabis over a 2 year period. Patient demographics, pain origin, and Global Physical Health (GPH) and Global Mental Health (GMH) scores were collected before intervention. Discontinuation rates were measured at three-month and one-year follow-up. Statistical analyses, including Fisher’s Exact Test and two-sample t-tests, were performed to assess associations between variables and discontinuation. The overall discontinuation rate of MC use was 57.9% at one year, with 44.7% of patients discontinuing within the first three months. Older age was significantly associated with higher discontinuation rates. Pain origin categories did not significantly differ between those who discontinued and continued MC use, although a higher proportion of patients in the discontinued group reported low back pain. No significant differences were observed in baseline GPH and GMH scores between the two groups. This study demonstrates a high discontinuation rate of MC use in patients for chronic musculoskeletal pain. The absence of significant differences in pain origin or baseline health scores suggests that factors beyond pain location or general health may contribute to the decision to discontinue MC. Further research is needed to explore the long-term effects of MC on pain management and patient outcomes.