Would love to see the same experiment repeated somehow, but for alcohol / partying. Then compare the two.
In college I was a residence hall advisor in a dorm that was advertised as being more studious, including a zero-tolerance policy on alcohol (students could be kicked out if seen even holding an empty beer can). I'm sure the grades in the dorm were higher, but hat dorm tended to attract students who were going to be more studious/less drunkenly already.
The 'drug and alcohol free' floor was probably among the worst in terms of drug use, alcohol use, partying, and worst of all, floorcest.