The use of drugs should be decriminalised, because drug addiction is a medical problem which criminalisation does nothing to solve. The war on drugs merely exacerbates the problem it claims to be dealing with. There is no evidence that the illegality of a substance ever stopped anybody from using it. If criminalisation worked, drugs would be difficult to obtain, which is not the case.
If drugs were fully legalised their production could be controlled for quality and safety in the same way that alcohol production is. Users would be much less inclined to experiment with potentially deadly ‘legal highs’ or adulterated substances bought on the street if they knew they could legally buy reliably produced drugs. Legally produced drugs could be taxed in the same way as alcohol and cigarettes and the proceeds could be ring-fenced for addiction treatment centres.