College students are using Adderall and Ritalin to boost "cognitive function and enables [which] them to study for hours with full concentration without getting fatigued" according to this NPR report. The report also says
"Students say Adderall and its cousin Ritalin are easy to get — bought and sold in the library, the cafeteria, the dorm, pretty much anywhere on campus. The going rate, they say, is typically $5 a pill. Unless it's exam week. Then, supply and demand kicks in and the price can shoot up to $25 a pill."
I guess the demand goes up then when students need an extra boost! But maybe the students just learned this from their professors. Read about that at Some Professors Pop Pills for an Intellectual Edge: Scientists say drugs help concentration. That article reports
"In an online survey of 1,400 readers published this month, the journal Nature found that 20 percent had taken pharmaceuticals for the nonmedical purpose of improving their concentration, focus, and memory. Most of the people who responded to the survey work in science, engineering, or education."