Substance abuse in U.S. adolescents is known to be associated with increased morbidity and mortality. In addition, illicit drug use has been linked to an increase in school dropout rates and the incidence of sexually transmitted diseases, including human immunodeficiency virus (HIV) infection. After a decline in the late 1980s and 1990s, adolescent drug use has apparently increased over the past few years. Brasseux and associates at the Children's National Medical Center in Washington, D.C. performed a 12-month study to determine the prevalence of drug use in adolescents attending their urban health clinic.

Adolescents from 12 to 21 years of age who presented for routine health care were included in the study. Urine specimens obtained from the patients were anonymously screened for the presence of five drugs: cannabinoids, cocaine, amphetamines, opiates and phencyclidine (PCP). All specimens that tested positive by immunoassay were sent to a reference lab for gas chromatography/mass spectrometry confirmation testing.

From April 1995 to March 1996, 1,313 patients (428 males, 885 females) were seen at the clinic. The mean age was 16 years. A total of 179 patients (14 percent) tested positive for one or more drugs. Of these, 166 tested positive for cannabinoids. Males were more likely to test positive for at least one drug (18 percent) than females (11 percent). Grouped by age, the highest overall use was among 18- to 21-year-olds, followed by 15-to 17-year-olds and then 12- to 14-year-olds. In a similar study of 1,312 adolescents tested from 1989 to 1990 for the presence of four drugs, only 5 percent had positive urine drug tests. There was a consistent increase in drug use, and cannabinoids in particular, in the more recent cohort. There was a decrease in cocaine use.

The authors conclude from their study that there has been a definite increase in drug use among adolescents seen at their clinic. The upward trend in marijuana use is consistent with drug-use trends reported by other national surveys. The results of this study are more significant in that most other data are from self-reported use, which may underestimate the prevalence of drug use. A particularly rapid rise in drug use among younger adolescents (from 12 to 17 years of age) was noted, with a greater than fourfold increase in drugs identified in the urine. The authors point out that physicians need to be aware that drug-use patterns may shift rather abruptly among adolescents, and counseling should focus on specific trends. Moreover, they believe that early interventions to discourage drug use and other risk behaviors must begin in elementary school.