Marijuana's official designation in the US as a Schedule 1 drug — something with "no currently accepted medical use" — means it has been pretty tough to study.
That remains the case, despite the fact that, at a state level, the drug is increasingly accessible for the general public. As of Election Day 2020, when Arizona, Montana, New Jersey, and South Dakota gave the green light to marijuana use for adults, 1 in 3 Americans live in a state where they can legally buy cannabis.
Despite the limitations to scientists studying the drug, a growing body of research and numerous anecdotal reports have found links between cannabis and several health benefits, including pain relief and the potential to help with certain forms of epilepsy.
In addition, researchers say there are many other ways marijuana might affect health that they want to better understand — including a mysterious syndrome that appears to make marijuana users violently ill.
Along with several other recent studies, a massive report released by the National Academies of Sciences, Engineering, and Medicine in 2017 helps sum up exactly what we know — and what we don't — about the science of weed. Here's what you should know about how marijuana affects the brain and body.