A good starting point for a critical delimitation could be the official definition from the World Health Organization (WHO), which states that the word “drug” is “[a] term of varied usage. In medicine, it refers to any substance with the potential to prevent or cure disease or enhance physical or mental welfare and in pharmacology to any chemical agent that alters the biochemical or physiological processes of tissues or organisms. Hence, a drug is a substance that is or could be listed in a pharmacopeia. In common usage, the term of the refers specifically to psychoactive drugs, and often, even more specifically, to illicit drugs, of which there is nonmedical use in addition to any medical use. Professional formulations (e.g., “alcohol and other drugs”) often seek to make the point that caffeine, tobacco, alcohol, and other substances in common nonmedical use are also drugs in the sense of being taken at least in part…