Students are aware of marijuana usage around campus, but most don't even acknowledge it as a problem. Caffeine is by far the leading drug on campus, though, and you will usually see students walking around with a coke of some kind or a coffee from Starbucks. Through the years, students who smoke cigarettes have become more prone to do it between classes, but it is still not such a problem that it affects those who don't smoke. As a student, you will find it difficult to resist caffeine, but tobacco and marijuana are not highly pushed on students because students are respectful of each other and their preferences.
Students at TSU will not openly admit using any drugs, and you will not notice it much. There is not peer pressure to take any drugs, and those who do smoke more than likely smoked before coming to TSU. Cigarette smokers are still a minority at TSU, and marijuana users tend to be secretly spread throughout the campus. There is little or no usage of harder drugs on or off campus; most students keep a level head about the things they do, because no one wants to be kicked out of school. On campus, marijuana usage is not known to be prominent; most of it happens off campus, which is to be expected due to the strictness of the administration. So, for an incoming student, the drug scene is not really something to worry about. Many students spend four years at TSU without even realizing it goes on. The main thing to keep in mind is that the drug scene really depends on who you hang with; so if drugs are a problem, be up-front about it, and choose your friends wisely.