Yes, yes, a thousand times yes
All reasonable people who don't actually live with their head permanently shoved up a portable possum's potty know by now that drug prohibition doesn't work. Even if by "work" you mean "reduce drug use", which is a stupid puritan attitude that's rooted in good old-fashioned spoilsportery. If you take a more humane definition of "work", e.g. "reduces human suffering", not only does it not work but it's the biggest fucking humanitarian disaster ever to be democratically enacted in law.
Of course if your definition of prohibition, the so called "War on Drugs" is "the increasing militarisation of global organised crime, supported by a policy of turning an increasing proportion of the elctorate into actionable criminals, while pouring money with one hand into the very cycles of violence we pretend to trying to eliminate by pouring money into the armed forces with the other hand", it works a treat. Not that you'd get anyone to actually admit that that's the working definition.
Anyway, shorter me: prohibition doesn't fucking work, mmkay? Turns out, however, that decriminalisation does.
Two things on that:
1. Sur-fucking-prise! Duh.
2. Way to go, Portugal!