You need to learn the difference between things that harm other people and things that only cause harm to the consentor.
In economics, harm to others not involved in the transaction are called negative externalities. You can see that murder, rape, theft and violence are negative externalities.
However, if someone consents to violent sex, the harm is done to one who is willingly involved in the transaction... There should be no crime. Maximisation of economic decision utility occurs when people are allowed to willingly enter into these transactions. There is not harm to others from the act of taking drugs alone.
Controlling other people's behaviour always leads to lower economic utility. There is an inevitable cost of the drug war... and mostly it's in the violence and crime of gangs that form and are empowered by being handed the black market drug trade. These same people, now wealthy (as a network) then go on to traffic in sex slaves and other things that do cause harm... they become efficient at it... because drugs are so overwhelmingly profitable. (highly demand inelastic -- use does not depend greatly on price / availability).