California legalized medical marijuana 30 years ago — how changes like ‘THC inflation’ have made using it more complicated

California became the first US state to legalise medical cannabis 30 years ago, helping start a shift that has made cannabis products more varied and widely available. Researchers say this has created new options for patients, but increasingly potent products and a market focused on high THC levels can make finding suitable relief more difficult.

Since 1996, 41 states and Washington, DC, have legalised medical cannabis, while 24 states allow adult recreational sales; cannabis remains illegal under federal law. Experts describe “THC inflation” as a commercial race to increase potency, which may raise the risk of unwanted effects without improving therapeutic benefit. Manufacturers also offer products with specific mixes of compounds such as CBD, CBG and CBN, which researchers are studying for possible benefits and more tailored treatment.