There could be nasty side-effects twenty years down the road, so I'd rather abstain. It would totally suck to be forced to take those drugs to remain cometitive, so I hope they will keep those drugs in limited circulation until their safety can be proven beyond doubt.
First of all, the effects of these drugs have already been studied for many years. Modafinil was first experimentally used in the treatment of narcolepsy in 1986, so over 20 years ago. Second, what do you mean proven beyond doubt? Testing these drugs is a statistical process, so what kind of confidence interval are you willing to accept? Keep in mind, that becoming more confident in your statistics means more testing…
Now, I do not mind these drugs being distributed under presecritiption well before that, because it will be only a fraction of percent of the total population.