It is a shame that so many of these drugs are illegal and have been demonized, because they do have benefits for people at smaller doses as discussed. Some of the greatest work and innovation in the world has been created by people under the influence of one substance or another (from Picasso and his wormwood/absinthe to Steve Jobs and LSD).

In my own experience, I have used small doses of either amphetamines (both prescription and not), cocaine or various other narcotics (usually just dropped into a coffee) to take me through some big, demanding and complex projects. I know that this is not the 'correct' thing to say, but with self-control and knowledge about dosage, I can't think of a single downside to them being used in such a manner.

I can imagine that daily small doses would add up to a dependency which has its own ill effects.

Obligatory Bill Hicks quote:

“See I think drugs have done some good things for us, I really do, and if you don't believe drugs have done good things for us, do me a favor: go home tonight and take all your albums, all your tapes, and all your cds and burn 'em. 'cause you know the musicians who made all that great music that's enhanced your lives throughout the years.... rrrrrrrrreal fkin high on drugs.”