All on the Mind
Earlier this year, Nature, one of the world's leading scientific journals, carried out an informal survey of its (mostly scientific) readers. One in five of the 1,400 people who responded said they had taken Ritalin, Provigil or beta blockers (drugs that can have an anti-anxiety effect) for non-medical reasons. They used them to stimulate focus, concentration or memory. Of that one in five, 62% had taken Ritalin and 44% Provigil. Most users had somehow obtained their drugs on prescription or else bought them over the internet."
http://www.economist.com/science/displaystory.cfm?story_id=11402761