Origins and Pathways to Drug Abuse

Research Findings from February, 1999 Director's Report

This section lists selected summaries from NIDA funded research projects that investigate the origins and pathways to drug abuse. 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.

Several 'Endophenotypes' Have Been Described as Possible Markers for Drug Abuse Vulnerability

William G. Iacono and colleagues at the University of Minnesota have reported psychophysiological measures associated with increased risk for drug abuse. One example is based on "preception" -- ability to take advantage of the predictability of an aversive event to diminish its psychological impact; the second, on "antisaccades" -- the ability to generate a saccade in the direction opposite to an abrupt movement of tracking target. In the preception experiment, subjects watched the sweep hand of a clock and were told that a loud, unpleasant noise would be heard at infrequent times. Sometimes these blasts would be predictable by appearance of a warning stimulus; other times there would be no warning. Skin Conductance Responses (SCRs) and Heart Rates (HRs) were measures of how well the subjects made use of the warning information. Results showed that poor modulators -- individuals whose SCRs were higher for the predictable loud noises and whose HRs did not differentiate predictable from non-predictable -- had significantly more symptoms of alcohol and nicotine dependence. These results were interpreted as biologically based support for the theory that individuals at risk for substance dependence have poor inhibitory control related to a dysfunctional Behavioral Inhibition System (BIS). Taylor, J., Carlson, S.R., Iacono, W.G., Lykken, D.T., and McGue, M. Individual Differences in Electrodermal Responsivity to Predictable Aversive Stimuli and Substance Dependence. Psychophysiology, 36, pp. 1-6, 1998. In the antisaccade experiment, subjects are required to make an eye movement in the direction opposite to a moving target which is contrary to natural tendency. Those who are less successful are said to have a more faulty control on inhibitory mechanisms. The results showed a higher error rate in this task among "high risk" 17 year-old boys compared to "low risk" boys. (High and low risk are defined as to whether fathers did or did not have a diagnosis of illicit drug abuse or dependence with co-morbid antisocial personality disorder). Additionally MZ twins discordant for drug abuse/dependence were nevertheless concordant for high error rates, suggesting a genetically based susceptibility for this deficit independent of diagnosis. Iacono, W. G. Identifying Psychophysiolgical Risk for Psychopathology: Examples from Substance Abuse and Schizophrenia Research. Psychophysiology, 35, pp.1-17, 1998.

Lowered P300 Electrical Evoked Responses were Associated with Drug Abuse Vulnerability

Iacono and colleagues demonstrated that the commonly reported electrical evoked response potentials (ERP) -- P300 -- to rare stimuli had a major genetic component because the amplitude was correlated by as much as .87 between one hemisphere of a monozygotic twin to the other hemisphere of the co-twin. Several studies in Iacono's lab showed that a reduced amplitude of this ERP was found in individuals with substance abuse problems or those at risk. In one study, there were significantly more cases of alcohol, illicit drug, and nicotine dependence among individuals with small P300 amplitudes than among the group with large amplitudes. Secondly, lower P300 amplitudes were reported in men who had alcohol abuse either alone or co-morbid with antisocial personality disorder, drug dependence, or both (smallest amplitude). Lower amplitudes were also reported in 17 year-old boys whose fathers had these diagnoses. Finally, there were lower P300 amplitudes in 17 year-old boys who subsequently (3 years later) developed an illicit drug abuse/dependence or nicotine dependence. Iacono, W.G. Identifying Psychophysiolgical Risk for Psychopathology: Examples from Substance Abuse and Schizophrenia Research. Psychophysiology, 35, pp.1-17, 1998.

Drug Use in Sons of Fathers with Substance Use Disorders

In a study using the CEDAR cohort at the University of Pittsburgh to determine the relevance of preadolescent psycho-pathology and substance use for predicting early adolescent alcohol and cannabis involvement, sons of substance dependent fathers (High Risk or HR, n=102) and sons of fathers without lifetime substance use disorder diagnoses (Low Average Risk or LAR, n=164) were assessed at age 10-12 and again at ages 12-14 using similar semistructured interviews that obtained measures of psychopathology and substance use behavior. Preadolescent tobacco experimentation and early adolescent regular alcohol use were more prevalent in HR than in LAR subjects. Logistic regression analyses were conducted to evaluate the effects of preadolescent psychopathology and substance use behavior on early adolescent substance use behavior. Preadolescent conduct disorder and tobacco use were found to be highly predictive of early adolescent marijuana use. Preadolescent conduct disorder alone predicted adolescent alcohol use. Adolescent tobacco use was predicted by the presence of preadolescent oppositional defiant disorder. Preadolescent anxiety disorders appeared to protect against adolescent tobacco use. The association between early cigarette smoking in preadolescence and later adolescent smoking of marijuana found in this study suggests that reduction of childhood tobacco use may be a valuable goal for prevention programs that seek to forestall the developmental trajectory toward cannabis and other drug use behavior. Clark, D.B., Kirisci, L., Moss, H.B. Addictive Behaviors, 23, pp. 561-566, 1998.

Familial and Nonfamilial Factors in the Prediction of Disruptive Behaviors in Boys at Risk of Substance Abuse

Researchers using the CEDAR cohort sought to identify (1) a core disruptive behavior disorder (DBD) postulated to presage a substance use disorder, and (2) the relative importance of parental DBD phenotypes, and familial and nonfamilial environmental factors in the determination of DBD in male children (aged 10-12 yrs). DBD symptom counts and measures of familial and nonfamilial environmental variables were collected from intact families ascertained through the presence (SA+) or absence (SA-) of substance dependence in fathers. DBD symptom counts for sons were based on symptoms of Conduct Disorder (CD), Oppositional Defiant Disorder (ODD), and Attention Deficit Hyperactivity Disorder (ADHD); counts for parents reflected historical CD and ODD and current Antisocial Personality Disorder (ASPD). Sons' psychiatric assessments were based on K-SADS-E interviews with sons supplemented by mothers' reports on their sons. Familial environmental factors reflected the shared environment including social and physical aspects of the neighborhood and the home, and nonfamilial environmental variables referred to similar factors impacting only individual family members. Multivariate analyses revealed that both behavioral symptoms and environmental measures were significant discriminators of the families. In SA+ families, the child's DBD score was best predicted by magnitudes of parental dyssocial behaviors and by familial environmental factors. However, in SA- families, only familial environmental factors were significant predictors of the child's DBD. These findings suggest that in addition to independent contributions of familial and nonfamilial factors, strong genotype-environment interactions may determine DBD in children and that may contribute to the liability for a substance use disorder. Majumder, P.P., Moss, H.B. Murrelle, L. Journal of Child Psychology & Psychiatry & Allied Disciplines. Vol. 39(2), pp. 203-213, 1998.

Family Values and Adolescent Problem Behaviors

This 18-year study explored the influence of early family values on adolescent problem behaviors in 199 conventional and nonconventional families. Many of the nonconventional parents in this study identified with and were involved in the countercultural movements of the 1960's. Children raised in such families were more likely to be exposed to multiple risks associated with counterculture lifestyles such as drug use. The longitudinal nature of this study offers a unique opportunity to investigate intergenerational values transmission in families who have been followed since their children were born. In addition, children with more serious problem behaviors, such as heavy drug users and dropouts who often are excluded from other studies, have been retained in this sample. Factor analyses of the values of the mothers at the first trimester of their pregnancy were replicated among the adolescents 18 years later and revealed two value dimensions: Traditional/achievement and humanistic/egalitarian. Mothers also reported the extent of their identification with and commitment to the 1960's counterculture. Adolescent problem behavior was indicated by drug use, delinquency, high school dropout, and sexual behavior. The longitudinal predictive path model was tested with latent variable structural equation models. Early maternal values predicted similar adolescent values. The positive and significant correlations between the values of mothers and their teenage children suggest intergenerational transmission of values rather than evidence of a generation "gap" in values. Teens, at an age when rebelling and questioning authority is common, did not develop substantially different values than their mothers. Traditional values of the mother and the adolescent protected the adolescents against problem behaviors. Adolescents higher in both traditional/achievement and humanistic/egalitarian values reported less delinquent behavior. Humanistic/egalitarian values increased drug use risk. However, maternal countercultural identity protected adolescents against hard drugs. Generally, a stronger commitment to values reduced the risk that adolescents would become involved in severe problem behaviors. An important finding of this study is that the greatest risk factor for problem behaviors was the lack of commitment to any set of meaningful values. Garnier, H.E., and Stein, J.A. Values and the Family: Risk and Protective Factors for Adolescent Problem Behaviors. Youth & Society, 30, pp. 89-120, 1998.

Genetic and Environmental Risk Factors in Cannabis Use, Abuse, and Dependence: A Study of Female Twins

This study examined the role of genetic and environmental risk factors in the development of cannabis use, abuse and dependence. Analyses of interviews with 485 monozygotic and 335 dizygotic female twin pairs demonstrated that both genetic and familial-environmental factors explained liability to cannabis use, while heavy use, abuse, and dependence symptoms were solely related to genetic factors, with heritabilities ranging from 62%-79%. Thus, while family and social factors play a key role influencing the risk to initiate cannabis use, heredity appears to determine the progression to abuse and dependence. These findings in women are consistent with other studies of genetic factors in drug abuse liability in men. Kendler, K.S., Prescott, C.A. Amer. J. of Psychiatry, 155(8), pp. 1016-1022, 1998.

Genetic and Environmental Risk Factors in Cocaine Use, Abuse, and Dependence: A Study of Female Twins

A study of cocaine use in monozygotic and dizygotic female twin pairs found that both genetic and environmental factors accounted for twin resemblance in liability to cocaine use, while resemblance for cocaine abuse and dependence symptoms was due solely to genetic factors. Heritability for cocaine abuse was estimated at 0.79. These findings are consistent with those of other studies of male veterans, adoptees, animals, and other drugs, and highlight substantial individual variation in liability to cocaine abuse and dependence. Family and social factors, toward which interventions might be targeted, are most salient to issues of drug initiation. Kendler, K.S. and Prescott, C.A. British Journal of Psychiatry, 173, pp. 345-350, 1998.

Social Context Effects in Development of Adolescent Substance Use

This article demonstrates a latent growth curve methodology for analyzing longitudinal data of adolescent substance use. Hypotheses concerning the form of growth in alcohol, cigarette, and marijuana use, and covariates influencing the form of growth, were tested. Participants were male and female adolescents (N=664) assessed at three time points. A common trajectory existed across the developmental period with significant increases in all three substances. Second-order multivariate extensions of the basic latent growth modeling framework suggested that associations among the individual differences parameters, representing growth or change in various substance use behaviors, could be adequately modeled by a higher-order substance use construct. Inept parental monitoring, parent-child conflict, peer deviance, academic failure, gender, and age, were significant predictors of initial levels and the trajectory of substance use. Duncan, S.C., Duncan, T.E., Biglan, A., and Ary, D.V. Contributions of the Social Context to the Development of Adolescent Substance Use: A Multivariate Latent Growth Modeling Approach. Drug and Alcohol Dependence, 50, pp. 57-71, 1998.

Progressions of Alcohol, Cigarette, and Marijuana Use in Adolescence

A study at the Oregon Research Institute examined the progression of alcohol, cigarette and marijuana use among adolescents based on level of use as well as dichotomous use or nonuse. The investigators applied latent growth curve analysis to study the relative impact of level of use of prior substances on use of target substances in the following year and development of use over a 4-year period. Subjects were 374 males and 389 females with a mean age of 13.23 yrs. at first assessment. They and their parents completed a series of self-report questionnaires. The study examined three models to determine (1) the effect of prior cigarette use on alcohol use and development and the relationship between change in cigarette use and the development of alcohol use (N=115), (2) the effect of prior alcohol use on cigarette use and development and the relationship between change in alcohol use and the development of cigarette use (N=199); and (3) the effect of prior alcohol and cigarette use on marijuana use and development, and the relationship between change in alcohol use and cigarette use and the development of marijuana use (N=287). Results showed that level of cigarette use predicted subsequent levels of alcohol use 1 year later among previous nonusers of alcohol and that, over the 4-year period, those who increased their cigarette use developed faster in their use of alcohol. Marijuana use was predicted better by cigarette use than alcohol use, and higher users of cigarettes at T1 were not only more likely to be higher users of marijuana at T2 but also to increase more rapidly in their use of marijuana over the next 4 years. Duncan, S.C., Duncan, T.E., & Hops, H. Journal of Behavioral Medicine, 21, pp. 375-388, 1998.

Effect of Father Involvement on Adolescent Substance Use

This study examined the effects of family process, father involvement, and family structure on 679 urban African-American adolescents, 14-17 year olds (50% female). Findings revealed that involvement of fathers, whether or not they live with their adolescent child, was associated with less substance use and psychological distress. Father effects were mediated by parental support and family conflict. Family structure was not related to any drug use or psychosocial outcome. The results challenge the assumption that nonresident fathers are absent from urban African-American youth's lives and that living in single mother households has adverse effects on youths' development. These findings, which replicate those in another sample, suggest single mother households do not automatically translate into absent fathers, and that interventions that focus on fathers in particular may be a useful approach for drug prevention programs. Salem, D.A., Zimmerman, M.A., Notaro, P.C. Family Relations, 47, pp. 331-341, 1998.

Prospective Study of Tobacco Smoking and Substance Dependencies Among Samples of ADHD and Non-ADHD Participants

This study focused on a group of young adults who as children had attention deficit/hyperactivity disorder (ADHD). The study participants were part of a longitudinal study of the life histories of 492 children, one third who were identified as hyperactive in 1974 and whose childhood symptom ratings and medical histories were used to establish the Diagnostic and Statistical Manual of Mental Disorders (3rd edition., revised DSM-III-R) ADHD diagnoses. The objectives of the study centered on describing (a) develop- mental history of tobacco use among ADHD and non-ADHD participants in a longitudinal sample, (b) the characteristic adult patterns of tobacco use from early adolescence through early adulthood, and (c) the relationship between ADHD status and tobacco and substance dependence outcomes. Adult data were obtained for 81% of the original 492 participants. Lifetime and current tobacco use were assessed from child, adolescent, and adult data, yielding eight measures of smoking status. The study showed that participants with and without ADHD did not differ in age of initiation to smoking, but there was a significant difference in the age smoking regularly began. By age 17, 46% of all participants with ADHD, as contrasted with 24% of the age-mate controls, reported smoking cigarettes daily. In adulthood, the proportion of participants with ADHD who were current smokers (42%) continued to exceed that of the age-mate controls. There were significantly different lifetime tobacco dependence rates - 40% compared to 19% for age mate controls. The rates for cocaine dependence were 21% for participants with ADHD and 10% for age mate controls. The rates for stimulants were 20% for participants with ADHD and 11% for age mate controls. Results were interpreted to support a possible link between ADHD treatment histories, and levels of tobacco smoking and tobacco dependence in adulthood. Lambert, N. and Hartsough, C. Prospective Study of Tobacco Smoking and Substance Dependencies Among Samples of ADHD and Non-ADHD Participants. Journal of Learning Disabilities. 31(6), pp. 533 Ð544, 1998.

Marijuana Use and Academic Achievement in Mexican American Students

This study sought to examine the relationship between academic achievement (as measured by standardized achievement scores), substance use, and related psychosocial factors among Mexican American school-age students. Surveys were conducted with 2,165 middle school students who identified themselves as Mexican American. Survey items asked about use of marijuana in the last year, as well as indices of student characteristics (susceptibility to peer influence, dysphoria, school satisfaction, self-esteem, academic achievement). Results of the analyses revealed a complex relationship among risk factors, marijuana use, academic achievement, and gender. One risk factor in particular, peer susceptibility, distinguished marijuana users from non-users, regardless of level of academic achievement for both males and females. In addition, a higher percentage of males than females were found to smoke marijuana, suggesting that, even among students who were academically talented, males were more susceptible to marijuana use than females. The findings suggest that prevention and mediation programs should focus their efforts on risk factors that may be applicable for all students (such as peer susceptibility) in addition to targeting risk factors that are more significant for identified subgroups, such as males and females. In this way, the complex issue of substance use and abuse among our young can be addressed more effectively. Codina, G.E., Yin, Z., Katims, D.S., and Zapata, J.T. Marijuana Use and Academic Achievement Among Mexican American School-Age Students: Underlying Psychosocial and Behavioral Characteristics. J. Child & Adolescent Substance Abuse, 7(3), pp. 79-96, 1998.

Patterns of Cigarette Smoking in Late Childhood

Early initiation of cigarette smoking so strongly predicts future smoking that several investigators have advocated delaying the age of initiation as a prevention strategy. To complement retrospective studies of early initiation, this study assessed prospectively patterns of smoking behavior in a sample of 401 children who were surveyed in the 4th, 5th and 6th grades. The principal findings were: (1) modeling of smoking by parents and friends is sufficient to influence children to initiate smoking, particularly when children also have low behavioral self-control, and (2) when modeling occurs in combination with poor adjustment to school, low parental monitoring, easy access to cigarettes, and other risk attributes, early initiators are significantly more likely to continue smoking. Jackson, C. et al., A Longitudinal Study Predicting Patterns of Cigarette Smoking in Late Childhood. Health Education and Behavior, 25(4), pp. 436-447, 1998.

Childhood Maltreatment and Pathology among Adult Substance Abusers

The purpose of this study was to examine predictive relationships between types of childhood maltreatment and personality disorders in a substance-abusing population. 339 drug- or alcohol-dependent patients completed a retrospective measure of childhood trauma, the Childhood Trauma Questionnaire (CTQ), and a self-report inventory assessing DSM-III-R personality disorders, the PDQ-R. Structural equation models revealed several significant paths between types of childhood maltreatment and personality disorder clusters and subclusters. Physical abuse and physical neglect were related to a subcluster of "psychopathic" personality disorders, consisting of childhood and adult antisocial personality traits and sadistic traits. Emotional abuse emerged as a broad risk factor for personality disorders within Clusters A, B, and C. Emotional neglect was related to the trait of schizoid personality disorder, which formed its own separate factor. Sexual abuse, which had been expected to predict borderline personality disorder traits, was not significantly related to any disorder cluster. This particular result may be due to the preponderance of males in the sample. These findings support the view that child maltreatment contributes to the high prevalence of co-morbid personality disorders in addicted populations. Bernstein, D., Stein, J.A., and Handelsman, L. Predicting Personality Pathology Among Adult Patients with Substance Use Disorders: Effects of Childhood Maltreatment. Addictive Behaviors, 23, pp. 855-868, 1998.

Role of Fetal Alcohol Exposure in Adult Substance Dependence: Adoption Design

This study used data from a previous adoption study to examine differences in substance use disorder outcomes between adoptees with fetal alcohol exposure and those without. Historical records were used to define fetal alcohol exposure. Results demonstrated that adoptees exposed to alcohol in utero reported higher symptom counts for alcohol, drug and nicotine dependence, and that these relationships held even when several confounding genetic and environmental variables were controlled for. Data was not available to assess the confounding roles of nicotine exposure or other prenatal variables, which may play a role in this relationship. Nonetheless, this study highlights the potential important role of in utero alcohol exposure in the development of later substance abuse and dependence. Yates, W.R., Cadoret, R.J., Troughton, E.P., Stewart, M., Guinta, T.S. Alcoholism: Clinical and Experimental Research, 22(4), pp. 914-920, 1998.

Parental Substance Use Disorder, Mediating Variables and Adolescent Drug Use

Investigators at the National Opinion Research Center conducted a study to develop and test a non-recursive model that examines the effects of parental psychoactive substance use disorder (PSUD) on the reciprocal relationships among stressful life events, family attachment, peer drug use and adolescent drug use. A 3 yr. prospective cohort study followed 777 10-16 yr-olds who belonged to 3 types of families: 214 who belonged to families in which a parent was diagnosed with PSUD, 181 who belonged to families in which a parent was diagnosed with an affective disorder (but no comorbid PSUD), and 382 who belonged to families in which both parents were free of any diagnosable disorder. Two follow-up interviews of subjects were used to measure stressful life events via the junior High Life Experiences Survey, family attachment via FACES-III (D. H. Olson et al, 1989) and a child-parent strain index, peer drug use, and 2 self-reported drug use scales designed to measure past-year alcohol use and illicit drug use. Findings show that subjects from PSUD families were at heightened risk of stressful life events, peer drug use, attenuated family attachments, and drug use during the 1st follow-up period. In turn, peer drug use was strongly associated with drug use during the 2nd follow-up period. Findings support the non-recursive model. Hoffmann, J.P, Su, S.S. Parental Substance Use Disorder, Mediating Variables and Adolescent Drug Use: A Non-Recursive Model. Addiction, 93(9), pp. 1351-1364, 1998.

Developmental Variations in Factors Related to Initial and Increased Levels of Adolescent Drug Involvement

This study was designed to examine the impact of maternal and adolescent factors on initial and increased levels of adolescent drug use in two groups of adolescents: younger adolescents (ages 12-14 at initial assessment) and older adolescents (ages 15-18). The adolescents and their mothers were interviewed at 2 points in time, 3 years apart. The results indicated that adolescent unconventionality is a crucial determinant for both initial and increased levels of drug use for both age groups, but intrapsychic distress is more important for the younger adolescent's initial use. Lack of maternal attachment and poor control techniques were associated with initial levels of drug use for both groups. However, the mother-child relationship and models of the mother's unconventionality had a greater impact on the older than on the younger group's increased involvement. Interactive results suggest that adolescents from both age groups who are well adjusted can offset the potential risks of maternal models of drug use. Brook, J.S., Jaeger, L., and Cohen, P. Developmental Variations in Factors Related to Initial and Increased Levels of Adolescent Drug Involvement. Journal of Genetic Psychology, 159(2), pp. 179-194, 1998.

Self and Peer Perceptions in Aggressive and Nonaggressive Boys

In order to examine self and peer perceptions in aggressive and nonaggressive boys during preadolescence and early adolescence, subjects completed differential ratings of themselves and of their peer partners following two brief dyadic discussion tasks with competitive directions and a game-playing task with a cooperative induction. Subjects also rated their expectations for self and peer behavior prior to the two competitive interaction tasks. Researchers later rated videotapes of the interactions. Aggressive boys had more distorted perceptions of dyadic behavior as they overperceived aggression in their partners and underperceived their own aggressiveness. These distorted perceptions of aggression carried over for aggressive boys into the third interactive task with a cooperative induction, indicating these boys' difficulty in modulating these perceptions when the overt demand for conflict is no longer present in the situation. Results also indicated that aggressive boys' perceptions of their own behavior after the first interaction task is substantially affected by their prior expectations, in comparison to nonaggressive boys who rely more on their actual behavior to form their perceptions. Lochman, J.E. and Dodge, K.A. Distorted Perceptions in Dyadic Interactions of Aggressive and Nonaggressive Boys: Effect of Prior Expectations, Context and Boys' Age. Development and Psychopathology, 10, pp. 495-512, 1998.

Pathways to Marijuana Use Among Adolescents: Cultural/Ecological, Family, Peer, and Personality Influences

This study examines the linkages, cultural/ecological factors, and major psychosocial risk factors as they relate to drug use in a sample from Colombia, South America. The participants were 1,687 adolescents living in mixed urban-rural communities in Colombia, South America. An individual interview was administered to youths in their homes by Colombian interviewers. The scales used were grouped into the following risk categories: (1) adolescent personality, (2) family traits, (3) peer factors, and (4) cultural/ecological variables. Results show that each of the domains was related to adolescent marijuana use, with some notable gender differences. Supporting a family interactional theory, the domains of family, personality, and peer factors were found to have a direct effect on the adolescents' marijuana use. Brook, J.S., Brook, D.W., De La Rosa, M., Duque, L.F., Rodriguez, E., Montoya, I.D., and Whiteman, M. Pathways to Marijuana Use Among Adolescents: Cultural/Ecological, Family, Peer, and Personality Influences. Journal of the American Academy of Child and Adolescent Psychiatry, 37(7), pp. 759-766, 1998.

Violence-Related Behaviors of Adolescents

This study examined the relations between two dimensions of parenting behavior and violence-related behaviors in 1,221 9th and 10th grade adolescents participating in Kids First. The higher the perceived responsiveness and demandingness of fathers and mothers, the lower the likelihood that adolescents had hit peers, beat peers, threatened a peer with a weapon or carried a weapon to school. Adolescents who perceived low levels of parental responsiveness and demandingness were two to three times as likely to report violence-related behaviors. This effect was stronger in females than males. Jackson, C. and Foshee, V.A. Violence-Related Behaviors of Adolescents: Relations with Responsiveness and Demanding Parenting. Journal of Adolescent Research, 13, pp. 343-359, 1998.