Legalize everything, have the government nationalize the narcotics industry, then make it all illegal once the government controls the supply.

It's absolutely crazy but it could work.

Making them legal and thereby probably cheaper would lower that treshold and get more people to try it.

Making it legal is not the same as having it commercially available, though. Heroin should be free and distributed with a prescription. Charging people anything for something they're ridiculously addicted to is a bad idea, since the demand for that substance will be highly inelastic.

Who would get such a prescription and for what reasons?

Pre-existing addiction, for the most part. So you'd have a special register for people dependent on high-risk drugs like heroin, methadone and the like.

People in rehab for these addictions being helped by not having them quit cold turkey?

The problem with that is people in heroin rehab are often given methadone as a substitute, which is more dangerous, and even then there's the significant possibility of still being locked up behind bars.

Drugs that aren't outwardly and blatantly harmful to anyone save for the one using them should all be legalized.

Would help shut down thousands of drug-trafficking businesses, and it honestly wouldn't make drug usage shoot up (heh) incredibly. I don't not do heroin and meth because they're illegal, I don't do them because they're heroin and meth.

I think Marijuana and the psychoactive drugs such as LSD, Magic Mushrooms, MDMA etc should be legalized. There's really nothing dangerous about them if you know what you're doing and the fact that legalization won't result in some dodgy cartel putting in any kind of chemical they want to financially cut corners.

That being said, I've expressed my concerns over opiates before. Not so sure if they should be decriminalized or not.