Epidemiology of Youth Drug Abuse

Research Findings from May, 2001 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 Abuse Among Athletes

Pope and his colleagues from McLean Hospital/Harvard School of Medicine have observed a substantial drug abuse problem among athletes in the U.S. In a survey of 511 clients entering five gymnasiums (Kanayama et al. 2000), they found that among men, 18% report use of androstenedione and/or other adrenal hormones, 25% report ephedrine use, and 5% report anabolic steroid use within the past three years; while among women, these rates were 3%, 13%, and 0%, respectively. Extrapolating from these figures to the U.S. as a whole, the authors estimate that possibly 1.5 million American gymnasium clients have used adrenal hormones and 2.8 million have used ephedrine within the last three years. They further report that nalbuphine may represent a new drug of abuse among athletes, especially those using anabolic steroids. (Nalbuphine, a nonscheduled opioid agonist/antagonist analgesic, is used for the treatment of pain.). Authors (Wines et al., 1999) conducted interviews on 11 subjects who reported nalbuphine use. Eight subjects were clinically dependent on nalbuphine, and seven of these experienced tolerance and withdrawal symptoms. Further, eight subjects who had never injected drugs intravenously before, reported using nalbuphine by this route. Nalbuphine-related morbidity was extensive and included medical complications and psychiatric symptoms (comorbid Axis I disorders). These observations suggest that nalbuphine may represent a new drug of abuse among anabolic steroids abusing athletes. Finally, the investigators (Halpern and Pope, 2001) also report that there is a widespread use of the Internet among well-educated adults and teenagers for obtaining medical information about hallucinogens and how to obtain and use these drugs. Kanayama, G., Gruber, A.J., Pope, H.G., Borowiecki, J.J., and Hudson J.I. Over-the-Counter Drug Use in Gymnasiums: An Underrecognized Abuse Problem? Psychotherapy and Psychosomatics, May/June issue, 2001; Wines, J.D., Gruber, A.J., Pope, H.G., and Lukas, S. Nalbuphine Hydrochloride Dependence in Anabolic Steroid Abusers. Am. J. Addictions, 8, pp. 161-164, 1999; Halpern, J.H. and Pope, H.G. Hallucinogens on the Internet: A Vast New Source of "Underground" Drug Information. American Journal of Psychiatry, 158, pp. 481-483, 2001.

A Model of Smoking Among Inner-City Adolescents: The Role of Personal Competence and Perceived Social Benefits of Smoking

Based on current trends, smoking will remain a major public health problem in the 21st century. Effective smoking prevention approaches offer the best hope for decreasing the rise in adolescent smoking rates. Competence enhancement approaches to smoking prevention are among the most successful. Yet, there is not a full understanding of how effective prevention approaches work. This study tested whether a deficiency in competence (poor decision-making skills and low personal efficacy) is linked to acquiring beliefs in the perceived benefits of smoking and whether these perceived benefits are then related to subsequent smoking. A sample of 1,459 students attending 22 middle and junior high schools in New York City participated. Students completed surveys at baseline, 1-year follow-up and 2-year follow-up during a regular class period. They self-reported smoking, decision-making skills, personal efficacy and beliefs in the perceived benefits of smoking. The tested structural equation model had a good fit and was parsimonious and consistent with the theory underlying the competence approach to smoking prevention. This research highlights the importance of addressing decision-making skills, personal efficacy, and beliefs in the social benefits of smoking within adolescent smoking prevention programs. Epstein, J.A., Griffin, K.W. and Botvin, G.J. A Model of Smoking Among Inner-City Adolescents: The Role of Personal Competence and Perceived Social Benefits of Smoking. Preventive Medicine, 31(2), pp. 107-114, 2000.

Preventing Illicit Drug Use in Adolescents: Long-Term Follow-Up Data from a Randomized Control Trial of a School Population

National survey data indicate that illicit drug use has steadily increased among American adolescents since 1992. This upward trend underscores the need for identifying effective prevention approaches capable of reducing the use of both licit and illicit drugs. The present study examined long-term follow-up data from a large scale randomized prevention trial to determine the extent to which participation in a cognitive-behavioral skills-training prevention program led to less illicit drug use than for untreated controls. Data were collected by mail from 447 individuals who were contacted after the end of the 12th grade, 6.5 years after the initial pretest. Results indicated that students who received the prevention program (Life Skills Training) during junior high school reported less use of illicit drugs than controls. Prevention effects were also found for specific illicit drugs including the use of hallucinogens and narcotics. This study shows that significant prevention effects are observable 5.5 years after the primary year of intervention. Botvin, G.J., Griffin, K.W., Diaz, T., Scheier, L.H., Williams C. and Epstein, J.A. Preventing Illicit Drug Use in Adolescents: Long-Term Follow-Up Data from a Randomized Control Trial of a School Population. Addictive Behaviors, 25(5), pp. 769-774, 2000.

Ethnic Identity Among Early Adolescents

A measure of ethnic identity, the Multigroup Ethnic Identity Measure (MEIM; J.S. Phinney, 1992), was examined with a sample of 2,184 11-15 yr olds who self-identified with a single race or ethnic group (mono-racial, n=1,812) or with 2 or more racial or ethnic groups (multi-racial, n=372). The psychometric properties and mean differences on the MEIM for White, mono-racial minority, and multi-racial early adolescents were investigated. Two factors were identified: (1) identification and (2) exploration. Identification was represented by items that reflect a sense of belonging and pride in an individual's ethnic group. Exploration was represented by items that characterize a search for ethnic group identity and participation in ethnic practices. Results show reliabilities for the 2 subscales with alpha = .84 for most individuals from mono-racial minority groups and multi-racial subgroups scored similarly on overall ethnic identity. Spencer, M.S., Icard, L.D., Harachi, T.W., Catalano, R.F., and Oxford, M. Ethnic Identity among Mono-racial and Multi-racial Early Adolescents. J. Early Adolescence 20(4), pp. 365-387, 2000.

Decreased Drug Reporting in a Cross-Sectional Student Drug Use Survey

Longitudinal cohort studies have suggested that reinterviews about drug use often lead to decreased reports of lifetime substance use (recanting). Respondents may edit their answers on reinterview because of perceptions regarding question threat. Since reinterviews usually occur after long periods of time, the influence of inadequate recall (memory), cannot be ruled out. In order to evaluate the relative importance of editing and memory on recanting, researchers examined a cross-sectional survey administered in 1993 to a probability sample of Illinois students who were in the 7th through 12th grade. Two sets of self-administered survey questions assessed drug use in this survey: the I-SAY drug-use questionnaire, and a supplemental questionnaire asked at the end of the survey. Rates of "new use " (i.e., cases where use of a drug was not reported in the I-SAY questionnaire but was reported on the supplement) with rates of recanting (use for a drug reported on the I-SAY but no use for the drug reported on the supplement). Findings indicate that recanting was generally more pronounced than was new use, especially for cocaine, heroin, marijuana, and inhalants. Those classified as light or inconsistent users on the I-SAY were significantly more likely to recant their drug use reports. Fendrich, M. and Mackesy-Amiti, M.E. Decreased Drug Reporting in a Cross-sectional Student Drug Use Survey. Journal of Substance Abuse, 11(2), pp. 161-172, 2000.

Methamphetamine Use by High School Students

Researchers at the Tri-ethnic Center for Prevention Research at Colorado State University analyzed data on 9th through 12th graders' methamphetamine use reported in the American Drug and Alcohol Survey (n=629,722). From 1989 through 1992, methamphetamine use rates remained relatively stable. Since then, rates have increased, almost doubling, especially in Western states. There were no significant differences in methamphetamine use across year in school, but males were more likely to use than females though use among females has also increased. American Indians and Hispanics were more likely to use methamphetamine, followed (in order) by Asian Americans, White non-Hispanics, and African Americans. Compared to other heavily drug involved youth, methamphetamine users were more likely to use other drugs. The most commonly reported other drugs used by students who used methamphetamine were alcohol, marijuana, hallucinogens, uppers, and cocaine. Methamphetamine users were also more likely than other drug users to suffer drug use consequences such as traffic tickets, car accidents, being arrested, trouble at school, fighting, and other adverse consequences. Oetting, E.R., Deffenbacher, J.L., Taylor, M.J., Luther, N., Beauvais, F., and Edwards, R.W. Methamphetamine Use by High Schools Students: Recent Trends, Gender and Ethnicity Differences, and Use of Other Drugs. Journal of Child and Adolescent Substance Abuse, 10(1), pp. 33-50, 2000.

Nicotine Dependence Rates Vary by Gender, Ethnicity, and Age

This study used data from the National Household Survey on Drug Abuse to look at the relationship between numbers of cigarettes used and symptoms of nicotine dependence, for various groups. The authors found that rates of nicotine dependence were highest among females, whites, and adolescents and younger adults (below age 50); each of these groups experienced more dependence symptoms while using the same or fewer number of cigarettes. Dependence rates increase sharply up to half a pack of cigarettes smoked per day. This study is unusual in using epidemiologic data from a large study to begin examining population prevalence and differential rates of nicotine dependence symptoms. It suggests that different thresholds of quantity and duration of smoking should be used in assessing different groups for risk for nicotine dependence, and that the risk for developing dependence increases sharply at lower levels of smoking (up to half a pack per day). Of particular note is the finding that adolescents, women, and whites were particularly vulnerable to the development of dependence symptoms at lower levels of consumption than their counterparts. Kandel, D.B. and Chen, K. Extent of Smoking and Nicotine Dependence in the United States: 1991-1993. Nicotine and Tobacco Research, 2, pp. 263-274, 2000.

Heritability of Tobacco Consumption Varies by Gender and Time Cohort

This article reports the largest and most comprehensive analysis to date of twin data yielding heritability estimates for tobacco use. The probands were obtained from a Swedish registry of twins born since 1886. By comparing monozygotic (MZ) and dizygotic (DZ) twin pairs, heritabilities for males was 56% with considerably lower contributions to the variance for use of tobacco; 24% and 20% for familial-environment and individual-specific environment risk factors, respectively. The pattern for females was not the same and subsequent analyses were needed to understand the differences. What seemed to matter for females was the era of their birth: those born in the first and second third of the cohort had much less heritability than those born in the last third (since 1940). In fact, those females born most recently had essentially the same heritability as males. The authors' conclude that "a reduction in the social restrictions on smoking in women in Sweden as the twentieth century progressed permitted genetic factors influencing the risk for regular tobacco use to increasingly express themselves."

A second result from this study is noteworthy. Twin correlations for amount of tobacco consumed were significant in MZ twins but not DZ twins, supporting the hypothesis that substance use is a two stage process: initiation and continued use (or misuse). Finally, the large number of twins studied allowed comparison of both MZ and DZ twin pairs who were either reared together or reared apart. This is important to address what is known as the "equal environment assumption" that assumes MZ and DZ twins are correlated in their exposure to their environment. In analyses addressing this issue, it was found that that the equal environment assumption was sufficiently valid so as not to introduce particular environmental biases due to zygosity. Kendler, K.S., Thornton, L.M., and Pedersen, N.L. Tobacco Consumption in Swedish Twins Reared Apart and Reared Together. Archives of General Psychiatry, 57, pp. 886-892, 2000.

Ethnicity and Gender in Polydrug Use

The purpose of this study was to determine if ethnic and gender differences in polydrug use exist among a cohort of inner-city adolescents during the three-year middle school period. Students in 22 urban schools completed self-report questionnaires with measures of drug use (smoking, drinking, and marijuana use) at three annual assessments. For participating students, (N=2354), analyses of variance were conducted to test for ethnic group (Asian, Black, Hispanic, and White) and gender differences in polydrug use. Ethnic differences were found for polydrug use measures at each assessment point. Asian and Black adolescents generally reported less polydrug use than White and Hispanic youth. When gender differences were evident, boys engaged in more use than girls. The relatively high rates of polydrug use indicate that prevention intervention programs that target multiple substances may be more efficient in reducing overall risk than prevention programs that focus on a single substance (e.g., smoking prevention only). Epstein, J.A., Botvin, G.J., Griffin, K.W., and Diaz, T. Role of Ethnicity and Gender in Polydrug Use Among a Longitudinal Sample of Inner-City Adolescents. Journal of Alcohol and Drug Education, 45, pp. 1- 12, Fall 2000.

Risk Factors for Early Tobacco Experimentation

This prospective study examines the relations between the mother's prenatal and current smoking and the offspring's smoking experimentation. A low SES birth cohort of 589 10-year-olds, who have been followed since their gestation, completed a self-report questionnaire about their substance use. Half were female, and 52% were African-American. Detailed data on exposure to tobacco and other substances in the prenatal and postnatal periods were collected from the mothers. During pregnancy, 52.6% of the mothers were smokers; 59.7% were smokers when their children were 10. Six per cent of the children (37/589) reported ever-smoking cigarettes, 3% had had one full alcoholic drink, and none had started to use other drugs. Maternal smoking during pregnancy was significantly associated with an increased risk of the child's tobacco experimentation. Offspring exposed to more than _ pack per day during gestation had a 5.5-fold increased risk for early experimentation. Structural equation modeling showed that prenatal tobacco exposure had a direct and significant effect on the child's smoking and that maternal current smoking was not significant. Prenatal tobacco exposure also predicted child anxiety/depression and externalizing behaviors, and these outcomes affected child smoking through the mediating effect of peer tobacco use. Cornelius, M.D., Leech, S.L., Goldschmidt, L., and Day, N.L., Prenatal Tobacco Exposure: Is It A Risk Factor For Early Tobacco Experimentation? Nicotine & Tobacco Research, 2, 45-52, 2000.

Paper vs. Computer-assisted Self Interview for Alcohol, Tobacco, and Other Drug Surveys

School surveys of alcohol, tobacco, and other drug use (ATOD) play an important role in evaluating prevention programs and developing policy. Until recently, most surveys are conducted with paper and pencil (PAP) instruments, but computer-assisted self-interviews (CASI) methods are becoming more common. Evidence on CASI methods indicates that they elicit higher rates of positive responses to sensitive questions than traditional measures. This study examines whether ATOD school surveys using CASI are feasible and improve the quality of data. Seventh, ninth, and eleventh grade students in two California communities were randomly assigned to PAP or to CASI (n=2296). The findings indicate that while CASI did not increase reported rates of substance use over PAP it significantly improved the speed of data processing and decreased the incidence of missing data. CASI was well accepted by students and school staff despite problems such as lack of computer resources. Hallfors, D., Khatapoush, S., Kadushin, C., Watson, K., and Saxe, L. A Comparison of Paper vs. Computer-assisted Self Interview for School Alcohol, Tobacco, and Other Drug Surveys. Evaluation and Program Planning, 23, pp. 149-155, 2000.