According to a study recently published in The Review of Economic Studies, access to legal marijuana may significantly reduce academic performance.
The study took advantage of a natural experiment in the Dutch city of Maastricht. In 2011, the city sought to pull back some of the marijuana tourism going to its coffee shops, where marijuana sales are legally tolerated. So through the local association of cannabis shop owners, it banned some foreigners of certain nationalities from buying pot at these venues.
This let researchers Olivier Marie and Ulf Zölitz, in the cleverly titled “‘High’ Achievers? Cannabis Access and Academic Performance,” compare the academic outcomes of Maastricht University students with varying levels of access to legal pot.
What they found: The students who weren’t allowed to legally access marijuana saw their grades significantly improve, especially in classes that require numerical and mathematical skills.
Here is the full Vox story. I strongly believe it is morally wrong to throw people in jail for smoking such substances, but still policy decisions have real consequences, we should know what those are, and I am not convinced that full availability of marijuana is the optimal approach.
Here are ungated copies, noting there have been significant revisions in the paper along the way.