Prohibition never works well...
We tried it here in the US with the 18th amendment... All that did was create an entire underworld of criminals, lots of profits to be had, lots of bad unintended consequences and lots of dead people and those in jail....

Most of what is commonly believed about Prohibition in the US is urban legend which happens to help the liquor industry. It did reduce alcohol consumption, significantly and permanently; the US has never got back to the consumption levels that preceded it. And it didn't lead to a measurable increase in violent crime:

http://jessnevins.com/blog/?p=89

There were spectacular instances of alcohol-related criminality, but the showbizworthiness of a class of crimes is a matter of reporting, not of what actually happened or how objectively damaging it was. Far more lives were saved by Prohibition than were lost by it. But people dying of liver failure, malnutrition, hypothermia or drunken brawls don't make the national media.

Serious restrictions on alcohol make sense. Serious restrictions on psychedelics don't.