Health and Developmental Consequences of Youth Drug Abuse

Research Findings from February, 2005 Director's Report

This section lists selected summaries from NIDA funded research projects that investigate the developmental implications of drug use. 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.

Morphine's Effects on Brain-Stimulation Reward Thresholds in Young and Aged Rats

There is a dearth of both human and animal research investigating whether there are changes in the rewarding properties of drugs as a function of age. There is evidence, however, that mu-receptor density decreases with age and that dopamine D1 and D2 receptors, which mediate the rewarding effects of mu opioids, also decrease with age. These changes raise the question of whether there are corresponding changes in the rewarding properties of the mu-receptor agonist morphine. This question was examined by Dr. Conan Kornetsky and his colleagues at Boston University using the brain-stimulation reward (BSR) procedure. It is well established that morphine and other abused drugs lower the threshold for BSR; however, the ability of an abused drug to alter the threshold for BSR has not been previously reported as a function of age. In the present experiment, the researchers compared the threshold for BSR (delivered into the lateral hypothalamic region of the medial forebrain bundle) and the ability of morphine to lower the BSR threshold in aged (24 months) and young (5-month) rats. The results indicated that while the older rats had a significantly lower baseline threshold for BSR, morphine produced a similar lowering of the BSR threshold in the two groups. These results suggest that the rewarding effect of morphine does not diminish with age, but rather is preserved. This lack of change in morphine's rewarding effects with age, despite evidence of decreases in opioid receptor density and compromises of the mesolimbic dopaminergic systems with age, warrants further investigation. Jha, S.H., Knapp, E.M. and Kornetsky, C. Effects of Morphine on Brain-Stimulation Reward Thresholds in Young and Aged Rats. Pharmacology, Biochemistry and Behavior, 79, pp. 483-490, 2004.

Early-adolescent Substance Use and Subsequent Young-adult Substance Use Disorders and Psychiatric Disorders

This study examined the associations among early-adolescent substance use, subsequent young-adult substance use disorders, and psychiatric disorders among a community sample of males. Early-adolescent data were collected in classroom surveys (1990-1993), and young-adult data were collected in face-to-face interviews (1998-2000). Results showed strong associations between early-adolescent substance use and young-adult substance use disorders and psychiatric disorders. The magnitudes of these associations varied by racial/ethnic group and were strongest among African Americans and foreign-born Hispanics, who reported the lowest early-adolescent substance use. These findings suggest that early-adolescent substance use is most strongly associated with a later pattern of dysfunction among the racial/ethnic groups that reported the lowest levels of early use. The implications of these findings in the context of primary and secondary prevention are discussed. Gil, A.G., Wagner, E.F., and Tubman, J.G. Associations Between Early-adolescent Substance Use and Subsequent Young-adult Substance Use Disorders and Psychiatric Disorders among a Multiethnic Male Sample in South Florida. Am J Public Health, 94, pp. 1603-1609, 2004.

Perceived Adverse Consequences Associated with MDMA/Ecstasy Use in Young Polydrug Users

The use of MDMA/Ecstasy has increased among young people in many industrialized nations around the world since the mid-1990s. In this paper, researchers describe how young people characterize perceived long-term consequences associated with Ecstasy. They used three data sources for this work (qualitative interviews, pile sorts, and quantitative data on subjective memory impairment). Contrary to expectations, Ecstasy was classified midway between drugs perceived to be the most and least risky. Risks associated with Ecstasy use included two popular myths implying forms of brain damage„"draining spinal fluid" and "creating holes in brains". Qualitative results indicated that some young people are concerned about the potential affects of the drug on memory and as a cause of depression. About 20% (82) of the participants (N =402) "agreed" or "strongly agreed" that Ecstasy has impaired their memories. Public health concerns about the potential adverse consequences of Ecstasy use have increased, along with a growing convergence of findings from neuropsychological studies that indicates a possible relationship between Ecstasy use and memory impairment and/or as contributing to other cognitive problems, but whether MDMA causes damage to serotonergic neurons in humans remains in question. Nonetheless, concern among young users about the adverse consequences of Ecstasy use may provide opportunities for reducing the prevalence of its use and the potential harm that it may cause. Carlson, R., McCaughan, J., Falk, R., Wang, J., Siegel, H., and Daniulaityte, R. Perceived Adverse Consequences Associated with MDMA/Ecstasy Use Among Young Polydrug Users in Ohio: Implications for Intervention. Intl J Drug Policy, 15, pp. 265-274, 2004.

Depression, Suicidal Ideation, and Suicide Attempt in Twins Discordant for Cannabis Dependence and Early-onset Cannabis Use

Previous research has reported both a moderate degree of comorbidity between cannabis dependence and major depressive disorder (MDD) and that early-onset cannabis use is associated with increased risks for MDD. The purpose of this study was to examine whether associations between both lifetime cannabis dependence and early cannabis use and measures of MDD, suicidal ideation, and suicide attempt persist after controlling for genetic and/or shared environmental influences. Drawn from a general population sample of twins (median age, 30 years), 277 same-sex twin pairs discordant for cannabis dependence and 311 pairs discordant for early-onset cannabis use (before age 17 years). The results showed that individuals who were cannabis dependent had odds of suicidal ideation and suicide attempt that were 2.5 to 2.9 times higher than those of their non-cannabis-dependent co-twin. Additionally, cannabis dependence was associated with elevated risks of MDD in dizygotic but not in monozygotic twins. Those who initiated cannabis use before age 17 years had elevated rates of subsequent suicide attempt (odds ratio, 3.5 [95% confidence interval, 1.4-8.6]) but not of MDD or suicidal ideation. Early MDD and suicidal ideation were significantly associated with subsequent risks of cannabis dependence in discordant dizygotic pairs but not in discordant monozygotic pairs. These findings suggest that the comorbidity between cannabis dependence and MDD likely arises through shared genetic and environmental vulnerabilities predisposing to both outcomes. In contrast, associations between cannabis dependence and suicidal behaviors cannot be entirely explained by common predisposing genetic and/or shared environmental predispositions. Previously reported associations between early-onset cannabis use and subsequent MDD likely reflect shared genetic and environmental vulnerabilities, although it remains possible that early-onset cannabis use may predispose to suicide attempt. Lynskey, M.T., Glowinski, A.L., Todorov, A.A., Bucholz, K.K., Madden, P.A., Nelson, E.C., Statham, D.J., Martin, N.G. and Heath A.C. Archives of General Psychiatry, 61, pp. 1026-1032, 2004.

The Natural History of Alcohol Use Disorders

This study examined clinically relevant research on the development, course and outcomes of adolescence alcohol use disorders (AUDs), using observational studies with adolescent samples selected for inclusion based on systematic assessment of AUDs and clinical relevance. Articles on childhood predictors, characteristics, course, complications and adult outcomes of adolescent AUDs were reviewed. Results indicate that the developmental trajectory toward adolescent AUDs begins with the emergence of childhood mental disorders. These problems are transmitted from parent to child in a developmentally specific fashion, reflect psychological dysregulation dimensions and predict adolescent AUDs. While most DSM-IV AUD diagnostic criterion items are valid for adolescents, tolerance and impaired control items are problematic, and some adolescents with significant alcohol problems are not identified by this diagnostic system. Understanding the psychosocial and biomedical complications that accompany AUDs requires attention to factors other than alcohol involvement itself, including childhood maltreatment and comorbid psychopathology. While some adolescents with AUDs manifest chronic alcohol dependence in adulthood, a substantial proportion overcome alcohol problems and transition to abstinence or normative drinking. While alcohol consumption may be the primary treatment focus, other important consequences, comorbidities and complications need to be addressed for successful developmental outcomes to result. Clark, D.B. The Natural History of Alcohol Use Disorders, Addiction, 99, pp. 5-22, 2004.

Adolescent Heavy Drinkers More Likely to be Obese Young Adults

This study examined the association of trajectories of heavy episodic drinking (at least five alcoholic drinks on one occasion) during adolescence with health status and practices at age 24. Data were from a longitudinal panel of 808 youths interviewed between 10 and 24 years of age. Results indicated four distinct trajectories of adolescent heavy episodic drinking were identified: nonheavy drinkers, late onsetters, escalators and chronic heavy drinkers. Overall, young adults who did not engage in heavy episodic drinking during adolescence had the lowest occurrence of health problems and were most likely to engage in safe health behaviors at age 24. Chronic and late-onset heavy episodic drinking during adolescence had negative effects on health status and practices at age 24. Adolescent chronic heavy drinkers were more likely to be overweight or obese and to have high blood pressure at age 24 than those who did not drink heavily in adolescence. Late-onset heavy drinkers were less likely to engage in safe driving practices at age 24 and were more likely to have been ill in the past year than adolescents who did not drink heavily. These health disparities remained even after current frequency of heavy episodic drinking at age 24, other adolescent drug use, ethnicity, gender and family poverty were controlled. Oesterle, S., Hill, K.G., Hawkins, J.D., Guo, J., Catalano, R.F., and Abbott, R.D. Adolescent Heavy Episodic Drinking Trajectories and Health in Young Adulthood. J Stud Alcohol., 65, pp. 204-212, 2004.

Cigarette Smoking and Depressive Symptoms: A Longitudinal Study of Adolescents and Young Adults

Cigarette smoking and depressive symptoms have been shown to be related in previous research. This paper examined the relationship between cigarette smoking and depressive symptoms in a longitudinal sample of 688 adolescents and young adults through surveys conducted over 13 years. The results indicate that a history of earlier cigarette smoking in adolescence predicts later depressive symptoms in the late twenties. The study also suggests that depressive symptoms during adolescence predict cigarette smoking in the late twenties but not above and beyond prior smoking. These results help clarify and expand current knowledge on the links between cigarette smoking and depression. The results point to several clinical implications for treatment of both cigarette smoking and depressive symptoms among both adolescents and young adults. Brook, J.S., Brook, D.W., Schuster, E., and Zhang, C. Cigarette Smoking and Depressive Symptoms: A Longitudinal Study of Adolescents and Young Adults. Psychological Reports, 95, pp. 159-166, 2004.

Tobacco Use and Health in Young Adulthood

This prospective longitudinal study examines the association between lifetime tobacco use and subsequent health problems by age 30. The authors interviewed a community group of 749 participants from upstate New York at mean ages of 14, 16, 22, and 27 years. Daily tobacco use during any of the time periods, as well as the number of periods of daily tobacco use, were significantly associated with increased risk for respiratory ailments, neurobehavioral and cognitive problems, and general malaise. The results suggested that daily tobacco use, either during childhood, adolescence, the early 20s, or a combination of those times, predicted health problems by age 30. Effective smoking prevention programs that begin in childhood are imperative to prevent the occurrence of later health problems. Brook, J.S., Brook, D.W., Zhang, C., and Cohen, P. Tobacco Use and Health in Young Adulthood. Journal of Genetic Psychology, 165, pp. 310-323, 2004.

Prediction of Violence Perpetration Among High-Risk Youth

A prospective study examined predictors of violence perpetration in emerging adulthood among high-risk adolescents using problem-behavior theory as a conceptual perspective and self-reported responses to questionnaires administered 5 years apart to 676 participants. Hard drug use, belief that hurting another's property while drunk was acceptable and high-risk group self-identification predicted later violence perpetration independent of baseline violence perpetration. Consistent with problem-behavior theory, personality, perceived environment, and behavior characteristics, beyond baseline violent behavior, predict risk for future violence perpetration in emerging adulthood; the effects of demographic variables are at best indirect. Sussman, S., Skara, S., Weiner, M.D., and Dent, C.W. Prediction of Violence Perpetration Among High-Risk Youth. American Journal of Health Behavior, 28(2), pp. 134-144, 2004.

Marijuana Use Associated with School Dropout and Truancy

This paper explores the relationship between adolescent marijuana use and school attendance. Data were pooled from the 1997 and 1998 National Household Surveys on Drug Abuse to form a sample of 15,168 adolescents, aged 12-18 years, who had not yet completed high school. The analysis determined the role of marijuana use in adolescent school dropout and, conditional on being enrolled, estimated the number of days truant. The potential endogeneity of marijuana use was tested in all specifications. The results indicate that any marijuana use was positively associated with school dropout and truancy in all models. However, when chronic marijuana use (weekly or more frequent) was distinguished from non-chronic marijuana use (less frequent than weekly), chronic marijuana use was found to be the dominant factor in these relationships. The results have important implications for educators, substance abuse treatment providers, and policymakers. Roebuck, M.C., French, M.T., and Dennis, M.L. Adolescent Marijuana Use and School Attendance. Economics of Education Review, 23(2), pp. 133-141, 2004.