Why present-oriented societies undergo cycles of drug epidemics

Musto (The American Disease, Yale University Press, New Homen, 1987) hypothesizes that cycles of drug use arise when the current generation of youth no longer remembers the adverse experiences of their forebears. This paper underlines this hypothesis through the results of an optimal control model of drug epidemics that incorporates an endogenous initiation function, models the reputation of a drug as being determined by memories of past use, and finds the optimal drug treatment strategy. Interestingly, unless the societal discount rate is quite low, if memories of past users decay moderately quickly, the optimal strategy is cyclic. Hence, not only do we find that 'those who forget the past are condemned to repeat it', but also that 'for those who forget the past and over-value the present it may even be optimal to have their future recreate the past'. These findings are illustrated by numerical analysis based on empirical data from the current US cocaine epidemic. (C) 2002 Elsevier Science B.V. All rights reserved.