Hanging out in marijuana cafes and smoking the night away is not exactly good for your grades, especially in math, according to a new study. Researchers drew this conclusion after comparing more than 54,000 grades of undergraduates in the Dutch city of Maastricht, where some were banned from the city's 13 cannabis coffee shops, the Guardian reports.
The upshot: The banned students had a 5% better chance of passing courses. For weaker students, the improvement in their chances rose to 7.6%. And the overall effect was a stunning five times higher for courses involving numbers and math.