I go further.
Legalizing drugs would actually reduce their use because of something called the salesman factor.
Presently, there are tens of thousands of pushers who have a strong interest in seeing the use of illegal dugs expand. So they give free samples, credit, and use all sorts of incentives to get people hooked.
If illicit drugs were legal, by contrast, most would be sold through government, or government-controlled, outlets that would not be able to advertise, let alone give away samples, and would almost certainly offer no credit.