swing and a miss.
peer pressure isn't the only means of drug introduction. some people just want to try shit and seek it out.
crack = drug, drugs =/= crack, you've made a massively broad statement based on a ridiculously narrow example.
some really smart people like to dabble, explore new horizons, open their minds in ways they wouldn't have been otherwise. some drugs do that.
some really smart, otherwise strong people end up in medically induced situations where all the mental strength in the world won't overcome the physical dependency their body develops. others can dabble in all sorts of shit but have a genetic makeup that doesn't develop that severe dependency.
really, really smart, adequately strong folks might like to get all sorts of bent but practice enough moderation and discretion that they have no negative impact from it.
some really stupid, weak, cowardly bastards never try drugs at all. there are absolutely straight edge criminals, wholly dependent CEOs and preachers, and everything in between.