“Medical Marijuana” May Do More Harm Than Good

These days, it’s hard to miss cannabis dispensaries. In the 40 states (plus DC) that have legalised medical marijuana, storefronts and advertisements promote cannabis as a treatment for virtually every condition, from chronic pain to anxiety to (ironically) drug addiction. Many consumers appear persuaded. In one survey, more than a quarter of adults in the United States and Canada have tried cannabis for medical purposes.

But how well-supported are these claims? A new review published in JAMA, the Journal of the American Medical Association, which attempted to examine every high-quality study from the last 15 years alongside guidelines from major medical societies, came to a sobering conclusion: For most uses, the evidence was limited or inconclusive. In many cases, medical organisations recommend against using cannabis because the evidence for harm outweighed potential benefits.