The opiate epidemic seems to me a US-specific case of deregulation, where doctors are essentially marketing these drugs to people where they won't required and

The opiate epidemic seems to me a US-specific case of deregulation, where doctors are essentially marketing these drugs to people where they won't required and without mechanisms to prevent doctor shopping, which I guess is similar to legalization but a bit more insidious. I would contrast that to Portugal where for all intents Heroin is essentially legal, but legal use is highly regulated and connected to rehabilitation programs. I think highly regulated legalization of drugs > unregulated legalizing of drugs OR prohibition of drugs (which by definition is unregulated). Whether prohibition is better than unregulated legalization depends on how effective your law enforcement is. In the US, the large number of illegal drug addicts is evidence that enforcement is ineffective. If we lived in an effective authoritarian state then prohibition would probably minimize harm, but even authoritarian states fail to stop drug use.