While you can guarantee some exposure to drugs, it is by no means a social prerequisite. There is enough to do at Brown and in Providence to stave off the boredom that makes the drug scene thrive at other less-entertaining schools. Brown students, like any college student body, look to drugs for both social and academic reasons. Many students drink and smoke cigarettes and pot casually. From there, the scenes are more obscure and are neither prominent nor hard to find. Students at Brown tend to view substance use as a luxury that can be enjoyed with personal responsibility. The effects that abuse will have on your work and the threat of University and police action if you get caught keep students using drugs sensibly on campus.
In the end, students are neither excluded nor included socially based purely on their drug habits, and Brown students exhibit the full spectrum of personal habits. The most important thing to remember is that most Brown students are responsible and goal-driven kids. Drug use is more a byproduct of college life than a main activity.