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Drug Use as Epidemic Phenomena

How do drug problems evolve over time?

Drug use spreads much like a communicable disease. That is, users are “contagious,” and some of those with whom they come into contact become “infected” (Musto, 1999). The diffusion of a new drug includes three stages: a) early stages, b) interaction process, and c) maturity stage. That is, a new drug diffuses slowly at first, then rises rapidly, and finally slows and levels off. Viewing addiction as an infectious disease provides insights into the course of an addiction outbreak and the most effective approach to prevent further spreading.

The idea of a drug epidemic captures the fact that drug use is a learned behavior, transmitted from one person to another, with the infected (user) transmitting the disease to vulnerable individuals. Early starters try out the new drug. Imitation and publicity spread the word. Diffusion, however, slows down as the target population gets saturated at some level. Eventually, the epidemic will run its course (Galea at al., 2004).

One characteristic that allows the epidemic to spread is the fact that the long-term adverse consequences of drug use have not yet appeared. At the earlier stages, drug use looks safe. Once the epidemic has gone on long enough to produce chronic intensive users, with all their adverse consequences, the epidemic will have run its course. The society will learn for itself that drug use is bad (Musto, 1999). The drug epidemics eventually die out when a new generation of potential users become aware of the dangers of drug abuse.

Knowledge of the possible adverse effects of drug use can act as a deterrent or brake on initiation. Once a drug has acquired a bad reputation, it does not seem prone to a renewed upsurge or contagious spread in use. For example, the popularity of cocaine in the late 1800s eventually faded when people saw the negative consequences of use and the drug became socially unacceptable.

This explains why long-term addicts are not particularly contagious. Often treatment programs require addicts to provide community service where they can serve as speakers to their peers of the experimenting population, to tell stories of the line between use and dependence, how they crossed it, and what the personal consequences were.

In short, as new drug generates enthusiasm, use rises. Then problems of over-dose, compulsion, and paranoia begin to appear among significant minority of users. Would-be recruits think twice. And the use declines. It is as if harsh experience immunizes a generation.

The appropriate drug policy instruments may differ depending upon the stage of epidemic. At the early stage of an epidemic, it may be wise to combine drug abuse prevention activities with law enforcement so as to minimize its spread. At later stages, when rates of initiation of drug use have slowed, it may be that the emphasis should shift to treatment. The important takeaway here is that intervention is highly effective in the beginning of an epidemic, but less so at its peak (Behrens et al., 2002). After some time the drug might lose its novelty appeal and the bad consequences of the drug become more visible. At this point intervention will have less of an effect, since there are fewer vulnerable in the population and the bad consequences is deterrence enough in itself.

A similar approach, known as the “broken windows” theory, centers on minor crimes such as vandalism, litter, graffiti, panhandling, and of course, broken windows. If the windows are not repaired, the tendency is for vandals to break a few more windows. The author of this theory, Wilson and Kelling (1982), argued that these lesser crimes are actually very important, because gone unaddressed they send the message that no one care, that you can get away with anything. In 1994, the strategy was successfully implemented in New York City with a significant drop crime rates.


Behrens, D.A., Caulkins, J.P., Tragler, G. & Feichtinger, G. [2002] “Why present-oriented societies undergo cycles of drug epidemics,” Journal of Economic Dynamics and Control 26 (6), 919–936

Galea S, Nandi A, Vlahov D. The social epidemiology of substance use. Epidemiology Review. 2004; 26:36–52.

Kelling, George L.; Wilson, James Q. Broken windows: the police and neighborhood safety. Atlantic Monthly. 1982 Mar; 249(3):29–38.

Kelling, George; Coles, Catherine (1997). Fixing Broken Windows: Restoring Order and Reducing Crime in Our Communities. New York: Simon & Schuster.

Musto, David (1999), The American Disease: Origins of Narcotic Control. Oxford University Press