Epidemiology of Youth Drug Abuse

Research Findings from February, 2002 Director's Report

This section lists selected summaries from NIDA funded research projects that investigate the epidemiology, etiology, and prevention research. The summaries provided were selected from recent issues of the Director's Report to the National Advisory Council on Drug Abuse. For a more comprehensive listing of NIDA funded projects see the Director's Report.

Drug Use and Lifestyle Among College Undergraduates: A 30-year Longitudinal Study

In order to examine trends in the prevalence of substance use and its relationship to attributes of lifestyle among college students over a 30-year period, Pope and his colleagues distributed anonymous questionnaires to seniors at a large New England college in 1999, using methodology identical to that they had used in 1969, 1978, and 1989. In 1999, the sample size was: 424 ‘non-users’, and 369 ‘users’. Most forms of drug use rose to peak in 1978, then fell over the next 21 years with the exception of MDMA. These observations were similar to those from the Monitoring the Future Study. For example, according to the MTF survey, the lifetime prevalence of marijuana fell from a peak of 65% in 1980 to 49.9% in 1998, similar to the authors’ findings of 76% in 1978 to 46% in 1999. Cocaine use fell from 22% in 1978 to 8% in 1999 (MTF), similar to their findings of 29.8% to 6.9%. MDMA use (which has now become the second most frequently tried illegal drug after marijuana) rose from 3.8% in 1989, 4.6% in 1997 to 6.8% in 1998, similar to authors’ numbers of 4.1% in 1989 and 10.1% in 1999. On several variables, college substance users differed more sharply from non-users in 1999 than in previous decades. In earlier decades, drug users differed from non-users only on visits to a psychiatrist and level of heterosexual activity. In 1999, the users and non-users differed in terms of homosexual activity and time spent in extracurricular activities. The authors conclude that although limited to a single institution, the findings suggest that college drug use has been declining, and that users have increasingly diverged from non-users in their values and lifestyles. Pope, H., Ionescu-Pioggia, M., and Pope, K.W. Drug Use and Lifestyle Among College Undergraduates: A 30-year Longitudinal Study, Am J. Psychiatry, 158, pp. 1519-1521, 2001.

Monitoring the Future (MTF) Study

Results from the MTF study were released on December 19, 2001. The findings summarized below focus on statistically significant changes from 2000 to 2001. This year's sample consisted of a total of 44,346 8th, 10th, and 12th grade students in 424 schools. For more information, go to http://www.nida.nih.gov and to http://monitoringthefuture.org, the MTF website at the University of Michigan.

Major Findings
The major findings of the 2001 MTF study were (1) a decrease in cigarette use by 8th and 10th graders from 2000 to 2001; (2) a slowing of the rise in MDMA (ecstasy) use; and (3) a decline in heroin use among 10th and 12th graders. With a few isolated exceptions, use of most other drugs and alcohol remained stable, as did most beliefs and attitudes regarding drug use.

The decline in cigarette use in the 2001 survey continued a general pattern of declining rates seen between 1996 and 2000. Decreases were observed in the lifetime, past month, and daily smoking measures for 8th and 10th graders. Past month cigarette use declined from 14.6 percent to 12.2 percent among 8th graders, and from 23.9 percent to 21.3 percent among 10th graders. 12th graders’ rates of smoking declined significantly from 1999 to 2000 and continued to decline, although not statistically significantly from 2000 to 2001. The increase in students' MDMA use reported in the last two MTF surveys slowed in 2001. While increases were observed in all three grades, they were generally not as steep as in the past two years and were not statistically significant. In addition, the perceived risk of harm from trying MDMA once or twice increased among seniors from 37.9 percent to 45.7 percent. Increases in perceived risk are often harbingers of future reductions in rates of use.

Lifetime and past year use of heroin decreased from 2000 to 2001 among 10th and 12th graders, and past month use decreased among 12th graders. For 10th graders, past year use decreased from 1.4 percent to 0.9 percent, and for 12th graders it was down from 1.5 percent to 0.9 percent. This decrease resulted largely from a decline in use of the drug without a needle (i.e., snorting or smoking it). For 12th graders, this year's decrease in heroin use reverses an increase between 1999 and 2000 that brought it to the highest level seen in the history of the survey; the rate for 2001, 0.9 percent for past year use, is the lowest since 1994.

Use of most other illicit drugs remained stable from 2000 to 2001. Illicit drug use rates are below their recent peaks in 1996 for 8th graders, but for 10th and 12th graders, they remain largely unchanged from recent peak levels seen in 1997. However, 27-year trend data for 12th graders indicate current levels of illicit drug use are well below their peaks in the late 1970s and early 1980s.

The Decline of Substance Use in Young Adulthood: Changes in Social Activities, Roles, and Beliefs

The Monitoring the Future team at the University of Michigan published a new book based on their longitudinal panel data. This volume examines how changes in social and religious experiences and changes in attitudes towards substance use among young adults are related to changes in substance use, family transitions, living arrangements, education, and employment. The analysis included over 38,000 young people followed from the initial survey, when they were high school seniors (age 18), into adulthood (up to age 32) and covers the last 25 years, a period when drug use and views about drugs underwent important changes. An earlier book by the MTF investigators showed that the new freedoms of young adulthood are associated with increases in substance use, while the responsibilities of adulthood--marriage, pregnancy, parenthood--contribute to later declines in substance use. The new findings clarify some of the mediators involved in these changes, such as religiosity and perceived risk and disapproval of substance use, factors whose importance is borne out even when controlling for a number of possible confounders. The initial freedoms of young adulthood often lead to frequent evenings out, parties and visits to bars, patterns that may be associated with increases in substance use, but later these behaviors are often crowded out by adult responsibilities to spouse and children. In addition to removing individuals from these higher-risk venues, engagement, marriage, pregnancy, and parenthood tend to heighten both disapproval and perceptions of risk of substance use. The study suggests that while these attitudinal variables are fairly stable, it is important to intervene early to strengthen them if substance use is to be reduced. The authors also discuss the need to intervene with younger adults prior to assumption of full adult roles to involve them in prosocial activities that will compete with substance use. Bachman, J.G., O'Malley, P.M., Schulenberg, J.E., Johnston, L.D. Bryant, A.L., and Merline, A.C. The Decline of Substance Use in Young Adulthood: Changes in Social Activities, Roles, and Beliefs. Mahwah, NJ, US: Lawrence Erlbaum Associates, Inc., Publishers, 2002.