Freedom to make an informed choice...
"The other thing to look at is why people take drugs. It's because their life is very unexciting/they have psychiatric problems/personal, family, financial problems/etc."
WRONG - most people take drugs, legal or illegal, because TAKING DRUGS IS FUN!!!
Now, I appreciate that not everyone has the same idea of what constitutes fun - some people would rather read a good book, or kick a football about, or go horse-riding (make sure you don't fall off!!) - and all activities carry some sort of risk - but there's still this undercurrent of puritanism in Western society that decrees that only medically-trained people should be able to decide if you can alter your consciousness, and that recreational use of pharmaceutical substances is somehow evil. Drugtaking is the last major taboo, and it's 'high' (ahem) time it was overturned.