Cannabis medicine for chronic pain: benefits and harms

Chronic pain, affecting around 100 million people in the United States, significantly impacts physical and mental health, productivity, and overall quality of life. Traditional treatments, including opioids and non-opioid medications, offer limited relief and are associated with adverse effects. This has driven the exploration of alternative treatments, including cannabis-based products, which may offer similar or better benefits with potentially fewer side effects.

Cannabis contains several active compounds, with the primary ones being tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is known for its psychoactive effects and potential for addiction, whereas CBD is believed to have analgesic and anti-inflammatory properties without these psychoactive effects. The ratio of THC to CBD in cannabis products can influence their effectiveness and side effects.

This systematic review, commissioned by the Agency for Healthcare Research and Quality (AHRQ), evaluates the benefits and harms of cannabinoids in treating chronic pain. The review focuses on placebo-controlled randomized controlled trials (RCTs) and cohort studies with concurrent control groups.The review included 18 placebo-controlled RCTs and 7 observational studies, categorizing cannabis products based on their THC-to-CBD ratios. The studies varied in design, patient populations, and outcomes measured. Products with high THC-to-CBD ratios were associated with moderate pain relief but also increased risks of sedation and dizziness. Products with comparable THC-to-CBD ratios offered small improvements in pain and function but also carried risks of dizziness and sedation. The evidence for products with low THC-to-CBD ratios (primarily CBD) and other cannabinoids was insufficient to draw definitive conclusions. Observational studies of patient-chosen cannabis products also provided limited and inconsistent evidence regarding their effectiveness and safety. In summary, while cannabis-based products show promise for managing chronic pain, their benefits are often accompanied by significant side effects.