Cocaine consumption in the United States : estimating past trends and future scenarios
A Markov model of population flows in and out of light and heavy cocaine use is presented. The model quantifies how the recent epidemic shifted from light use to heavy use. Projecting future consumption from hypothetical initiation scenarios suggests: (1) reducing initiation is vital; even temporary lapses can have lasting negative effects; and (2) even if initiation ceased immediately, the quantity consumed would decay with a half-life of more than a decade due to inertia created by current heavy users. Hence, reducing initiation is necessary, but not sufficient; measures that directly address consumption by heavy users are also needed.