Nootropics (Piracetam, Choline and so on) are often called supplements for the brain, although Piracetam, for example, is usually prescribed to the people suffering from dementia or Alzheimer's disease, therefore it's practically a type of medicine. Although they don't have any side effects, not even on a long term, can anyone become addicted to them if he/she takes them for too much time?
I'm not really sure so take what I say with a grain of salt, but I think most nootropics (if not all) are as addictive as sleeping pills, and a lot of those are placebo. Proceed with caution, if you start taking them regularly it might end up in addiction.
The thing is that they do work. I used to take Piracetam and choline when studying for the admission exam into the medical school and it helped a lot although I failed (by 0,04) to catch a place. However, not that I stopped taking them, I don't feel the urge to use them again. This is why I was asking in the first place.