The world’s first true “smart drug” enhances cognition 11 years ago
I actually take Modafinil for narcolepsy. It's not quite as life-changing as the recent articles make it out to be; it doesn't make you smarter or think faster or anything of the sort. It just removes the fog in your brain that builds up when you have too many things competing for attention.
One major downside, however, is it's fairly quick to build up an immunity to, especially if you have it as a medical prescription.
Overall, it's pretty useful, and as far as I know, harmless. Just don't expect it to be like the movie Limitless.