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Epidemiology
of Substance Use: Incidence and Prevalence
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Incidence:
Rate of new cases of a condition (or an event) during a given period
of time.
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| A good example of incidence data are the annual reports of "emergency room episodes" from the Drug Abuse Warning Network or DAWN program, which is sponsored by the National Institute on Drug Abuse. Hospitals that participate in the DAWN program submit an "episode report" for each incident in which a drug abuse patient visits their emergency room, including demographic information about the patient and information about the circumstances of the drug abuse episode. These episodes or incidents might involve an overdose, "the chronic effects of habitual drug use or unexpected reactions, i.e., the drug's effect was different than anticipated (e.g., causing hallucinations). Up to four different substances, in addition to alcohol-in-combination, can be specified for each ER episode" (NIDA, 1988, p. 3). To view a recent DAWN report on the incidence of drug-related ER episodes, click here. | ||
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Prevalence:
Rate of existing cases, both new and ongoing,
at a given point in time (or during a period of time).
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| Epidemiological data in the area of drug and alcohol problems are more likely to focus on the prevalence of substance use. The Monitoring the Future Project at the University of Michigan is a particularly useful source of data on the prevalence of illegal substance use by adolescents. This project has been collecting data on high school seniors since 1975, and it continues to conduct probability surveys of seniors and younger adolescents annually. The following graphs report the thirty-day prevalence of substance use for 2003 and the thirty-day prevalence of marijuana and cocaine use since 1975. | ||
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Increasing
Narcotic Use.
In contrast to relatively stable patterns of use for heroin and many other
illegal drugs over the past decade, the thirty-day prevalence of other
narcotic use by high school seniors has steadily increased since the early
1990s. "Other Narcotics" include opiate-type prescription drugs
such as codeine and Demerol when used outside of medical supervision.
In 2002 several new drugs, including Oxycontin (Oxycodone) and Vicodin
(Hydrocodone), were added to the list of other narcotics, which accounts
in part for the upturn in thirty-day prevalence between 2001 and 2002.
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