Cannabis provides some relief (with side effects) for chronic pain

Reference

McDonagh MS, Morasco BJ, Wagner J, et al. Cannabis-based products for chronic pain: a systematic review. Ann Intern Med 2022 Aug;175(8):1143-1153.

Synopsis

These authors searched 5 databases, including the Cochrane Library, to identify English-language randomized placebo-controlled trials and cohort studies (at least 1 month long) of cannabinoids for chronic pain. They found 18 controlled trials (n = 1740) and 7 cohort studies (n = 13,095), ranging in duration from 1 to 6 months, usually 4 to 8 weeks. Two investigators evaluated studies for inclusion and performed the data extraction and evaluation. Most patients had neuropathic pain, were White, and had baseline pain scores of 5 to 6 on a scale of 1 to 10 (with 10 being "worst pain imaginable"). Most of the studies were of moderate to high risk of bias, meaning the study was conducted in a way that could have introduced a systematic bias. For the important outcomes, there was a moderate amount of heterogeneity among the studies. Products primarily consisting of synthetic tetrahydrocannabinol (THC) were associated with a moderate improvement in pain scores (ie, a response of at least 30%). There was evidence of some benefit to balanced THC and cannabidiol (CBD) extracts delivered via sublingual spray. There was not enough study of extracts or whole plant products, or products primarily with CBD to draw conclusions. No studies have shown an effect on overall functioning. Although rates of serious side effects were not adequately evaluated, dizziness and sedation were common with THC products.