A red herring. I believe that the illegality of drugs drive them underground, the very place where they cause the most harm to society. The desire to try drugs prompts otherwise law-abiding citizens to associate with criminals. Career drug dealers are likely to be involved in guns and gang warfare. Unregulated guns and gang warfare to me represent a far greater threat than a few self-inflicted overdoses. Civilians might get caught in the crossfire.
I don't think everyone should take drugs, but I do believe that making drugs (including "hard" drugs such as heroin) legal would address a large number of problems drugs cause in society.
In Holland (or more specifically, Amsterdam: I am not certain the approach extends to the whole country), drugs are not legal, merely "decriminalised" - people are breaking laws, but Amsterdam has made a decision to let them off. This strikes me as merely ignoring the problem.
A proper program of drugs legalisation would legitimise the trade in drugs. Trading standards authorities would perform random tests to ensure that drugs were not cut with battery acid. The treasury would raise taxes on the sale and import of drugs, but people would still buy these drugs, because most people would prefer to deal with a legitimate business than with a criminal underworld.
If drugs were legal, hospitals would stand more of a chance when faced with an overdose case. At present vital minutes are wasted trying to ascertain what the person took, and what he though he took: the packaging on a commercial pack of heroin would state clearly what dosage and what blend of substances were present.
Erm; this argument belongs on another node. Back to the point: Amsterdam does not present the role model for a society which tolerates drugs.