It seems like we can never make the leap to asking about the etiology of these do-called “diseases.” If we did we might be surprised at some of the anthropological data. Addiction, for example, is not a hazard of being human. It only occurs under certain social conditions, and does not occur among intact indigenous populations. That means that our society actual provides fertile ground for addiction. Addiction is not so much about defective or vulnerable individuals taking drugs, but is a direct consequence of how we live. This is especially evident if we expand the franchise and acknowledge other forms of addiction (eg shopping, digital devices, gambling, food). If we look at psychosis we see something similar. Folks suffering from psychosis are much more likely to heal in the undeveloped world. And in many cultures psychosis was regarded with something like awe. Meaning, it was understood in spiritual terms. It any of this is of interest, I highly recommend Bruce Alexander’s book, The Globalization of Addiction: a Study in Poverty of Spirit.