This is from a new study that was conducted by Review of Economic Studies. Wintery Knight has the report:
This is from the radically leftist fake news site Washington Post, of all places. Thankfully, the study was done by scientists, not by journalists.
The most rigorous study yet of the effects of marijuana legalization has identified a disturbing result: College students with access to recreational cannabis on average earn worse grades and fail classes at a higher rate.
Economists Olivier Marie and Ulf Zölitz took advantage of a decision by Maastricht, a city in the Netherlands, to change the rules for “cannabis cafes,” which legally sell recreational marijuana. Because Maastricht is very close to the border of multiple European countries (Belgium, France and Germany), drug tourism was posing difficulties for the city. Hoping to address this, the city barred noncitizens of the Netherlands from buying from the cafes.