Legalise their use. Show people the video of what might happen to their health, sign on dotted line, put big D on their i.d card for druggie which means no driving, no teaching ,no piloting in fact nothing which can put the general public at risk with a loonngg prison sentence for those who don't comply. Age limit on use, even longer prison sentence for those who supply under age. Sell quality from licenced retailers, collect taxes, watch crime fall. Use only in private premises, any abuse long prison sentence. Nasty prisons, no t.v, no separate rooms,no day release, no holiday camp. No nhs treatment for drug related illnesses. Or fags or booze, make your choice live with the consequences.
Whilst we're doing this legalise the oldest profession. Check the health of those involved, get rid of pimps, collect the taxes, stop kerb crawling. Setup a regulated area say on an industrial estate most of which are less busy at night or in the evening, they are usually out of residential areas, go there, pay, do your business. It ain't gonna be stopped so make it safer for those involved and keep the nuisance away from those who don't want to be.