Similarly, studies of the pre-existing characteristics of alcoholics, smokers and compulsive gamblers also reveal an admixture of otherwise average citizens. Another factor to take into account is that the high mortality in drug addicts may cause selection of the 'fittest' while some less well equipped for the lifestyle may fall by the wayside. Certainly there are some long-time survivors of many years of street drug use. They are remarkable and resourceful people, many of whom could write a riveting life history. This could be explained on the basis of environment, genetic make-up or a combination of both.
Current research favours the latter.
There are few families which are not affected by addiction of some sort. This country also had an enormous consumption of opium in the nineteenth century. By contrast, it is sometimes stated that Asians share with Jews a low incidence of alcoholism. How much of this is due to genetics and how much to environment is still unclear. Theories about alcoholism may apply to other drugs although differences occur with the more complex pathways of metabolism for other drugs.