I personally believe the evidence is without question that illegal drugs as well as legal drugs contribute to behavior that is considered mental illness this doesn’t mean its all one way or another nor do I necessarily believe that the war on drugs as it currently stands is the best way of dealing with drug abuse nor do I believe blanket legalization solves the problem. I’ve seen people who before they began using were living perfectly normal lives which degenerated to crap as drug use over took their lives and I’m not just talking about illegal drugs. I know people who abuse nerve pills and prescription drugs and of course one of the most popular drugs that is abused is alcohol. I’d like to see a solution where someone could be given a pill to stop the addiction by interfering with the ability of the substance to bind to receptors in the brain or a form of vaccination where the body would treat the substance as a foreign invader and clear it as a part of the immune response. The infant technology is there but we will have to wait a bit longer for it to be realized.
Legalization isn't meant to solve the problem of drug use/abuse - that can only come one soul at a time - but to end the problems created or worsened by drug illegality, notably the hyperinflation of drug profits and channeling of those profits into criminal and terrorist hands.