Cannabis: short-term gain, but long-term pain?

A review of 25 trials and studies assessing cannabinoids has found that oral synthetic cannabis products with high THC-to-CBD ratios and extracted cannabis products with comparable THC-to-CBD ratios were associated with moderate, short-term chronic pain improvements. However, they were also associated with higher risks for adverse events and few benefits in overall functioning.

Researchers from Oregon Health & Science University reviewed 18 randomised, placebo-controlled trials, comprising 1740 participants, and seven cohort studies, comprising 13,095 participants, to evaluate the benefits and harms of cannabinoids for chronic pain.

They found that synthetic products with high THC-to-CBD ratios were associated with moderate improvement in pain severity and response but were also associated with an increased risk for sedation and dizziness.

The authors also found that small improvements in overall function were demonstrated for products with comparable THC-to-CBD ratios, but no improvements were demonstrated for products with high THC-to-CBD ratios. However, they determined that evidence for whole-plant products, CBD and other cannabinoids was limited by serious imprecision and lack of ability to assess consistency and study methodological limitations. Reviewed studies, noted the authors, did not evaluate harm outcomes including psychosis, cannabis use disorder and cognitive deficits, and studies did not include patients who were at higher risk for harms.

An accompanying editorial by authors from the University of Michigan Medical School advise clinicians to be willing to provide compassionate guidance to patients who use cannabis products by using a strategy of pragmatism and knowledge of patient experience, known cannabinoid effects and harm reduction. The authors highlight that this review can offer information to clinicians on routes of administration, the effects of CBD versus THC, dosing and potential adverse effects.

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