Why 'smart drugs' can make you less clever

It is an open secret: while athletes dope their bodies, regular office workers dope their brains. They buy prescription drugs such as Modafinil or Armodafinil on the internet's flourishing black market to boost their cognitive performance. It is hard to get reliable data on how many people take such "smart drugs" or "pharmacological cognitive enhancement substances", as scientists call them. Prevalence studies and surveys suggest, though, that people from different walks of life use them, such as researchers, surgeons, and students. In an informal poll among readers of the journal Nature, 20% reported that they had taken smart drugs. And it seems that their use is on the rise.