Structural stigma comes from policies and regulations, whether they're general laws or rules from within organizations. Fundamentally, our laws will dictate what we do in relation to drugs.
At its core, stigmatization is a process by which individuals are labelled as non-mainstream and immoral. As long as legislation is designed to punish and prohibit de facto substance use, there will certainly be stigmatization.
My presentation yesterday was about the importance of reducing the stigma of drug use rather than reducing drug use itself. People, and even ideologues who claim to be experts in the field, have spoken out on this issue. This is the case, for example, of Mr. Keith Humphreys, who wrote an article in The Atlantic containing many false arguments and many red herrings. Such people are relying on botched logic.
Structural stigma is caused by our laws. By prohibiting normal human behaviour that has existed since the dawn of time—and always will—we stigmatize, exclude and kill people. As I said, stigmatization has so many negative effects that, in the end, it kills people.