Another “This is Your Brain on Weed” Study Shows... Not Much Actually

A Critical Look at Cannabis Research

Stop me if you've heard this one before: Heavy cannabis use alters brain function.

At least, that's what breathless headlines are claiming about a new paper published in JAMA Open from a team led by Nora Volkow, director of the National Institute of Drug Abuse (NIDA)[1].The study concludes that "cannabis use is associated with short and long-term brain function outcomes, especially during working memory tasks." This tepid statement oversells what the authors actually found, but at least the authors managed to avoid using explicitly causal language. The media, predictably, showed no such restraint. CNN jumped straight to "more frequent cannabis use may damage an important memory skill."

Before I explain why this study—despite its impressive sample size and fancy brain scans—is about as revealing as an empty bowling lane, let me share something delicious from the authors’ own data: compared to both heavy users and non-users, moderate cannabis users showed optimal brain activation patterns…