Never used drugs personally, other than alcohol, so I can't comment from experience.
However, the prohibition against drugs now is just as ineffective as the one against alcohol back in the '20s. All it does is make the substances more dangerous to use, as there are no safety regulations that must be met, and gives money and power to criminals. In fact, the US War on Drugs is undermining their War on Terror. If heroin were legal, then the poppies required would be grown in Europe or North America. But, as it is, they are grown in Afghanistan, and are the main source of income for the Taliban.