Biomedical subjects

Duncan B Clark

Publications and source records attributed to Duncan B Clark.

At least 19 recordsLinked to original sources

PubMed2006

Testosterone levels and sexual maturation predict substance use disorders in adolescent boys: a prospective study.

BACKGROUND: This investigation determined whether testosterone level and sexual maturation in boys biased development of socially nonnormative behavior culminating in a substance use disorder (SUD). METHODS: The subjects were 179 boys recruited in late childhood through a high-risk paradigm. Path analysis was used to evaluate the influence of testosterone level and sexual maturation in early adolescence (age 12-14) on attitudes toward antisociality, affiliation with deviant peers, and social potency in middle adolescence (age 16), illicit drug use by late adolescence (age 19), and SUD in young adulthood (age 22). RESULTS: Testosterone level predicted social potency and approval of aggressive/antisocial behavior. Sexual maturation mediated the relation between testosterone level in early adolescence and later affiliation with deviant peers. Social potency, approval of aggressive/antisocial behavior, and deviant peer affiliations predicted illicit drug use by late adolescence that in turn predicted SUD in young adulthood. CONCLUSIONS: This study demonstrated that pubertal processes in early adolescence influence the risk for SUD via effects on psychosocial functioning.

Adolescent↗

PubMed2006

Early age of first sexual intercourse and affiliation with deviant peers predict development of SUD: a prospective longitudinal study.

OBJECTIVE: A recent study has reported that early sexual behavior predicts the development of substance use disorders (SUD). However, that relationship was considered by its authors to be only tentative, because it was based on cross-sectional data rather than longitudinal data. Another recent study reported that deviant activities of peers predict development of SUD, although that relationship has not yet been confirmed. The objective of this study was to assess whether early onset of sexual intercourse and affiliation with deviant peers serve as predictors of the development of SUD, using a prospective longitudinal study design. METHOD: We conducted a prospective longitudinal study of adolescents. These subjects were recruited at the age of 10-12years, with follow-up evaluations at ages 14, 16, 19, 22, and 25. The sample included 136 male subjects. Cox regression analyses were performed, with age of first intercourse, neurobehavioral disinhibition, exposure to drugs in the neighborhood, and deviant activities of peers as factors in the analyses. RESULTS: Earlier age at first intercourse and deviant activities of peers each predicted a significantly higher risk of subsequently developing a SUD (Wald=8.3, df=1, p=0.004; Wald=7.5, df=1, p=0.006, respectively). CONCLUSIONS: The results of this study confirm that early onset of sexual intercourse and affiliation with deviant peers predict the early development of substance use disorders, using a prospective longitudinal study design.

Adolescent↗

PubMed2006

Different lengths of times for progressions in adolescent substance involvement.

The present study examined Lengths Of Times for important transitions in substance involvement from Initiation to Regular use (LOTIR), first Problem from drug use (LOTIP), and first experience of Dependence (LOTID) for alcohol, tobacco, cannabis, cocaine, and opiates. Data were from a longitudinal study of 590 children (22.2% female) at different levels of risk for substance use disorders based on their fathers' substance use-related diagnoses. Participants' substance involvement was assessed at four ages: 10-12, and follow-ups at two, five, and eight years later. Results suggested that faster transitions were more due to drug-related constructs (including possible social milieus of different drug classes and interactions between drug class and neurophysiology) than intrapersonal constructs. The shortest transition times (and greatest addictive liabilities) were for opiates followed respectively by cocaine, cannabis, tobacco, and alcohol. Females had shorter transition times, though gender differences were small. Some evidence was found for a familial influence on transition times above what was accounted for by differences between substances.

Adolescent↗

PubMed2006

Substance use disorder trajectory classes: diachronic integration of onset age, severity, and course.

BACKGROUND: Substance use disorders (SUDs) may be characterized by onset age, severity, substance type, course, and outcomes. SUD phenotypes in the literature typically consider each of these features in isolation. Conceptual frameworks and data collection procedures for assessing SUD phenotypes are increasingly "diachronic" in approach, providing for characterizations "throughout time". The recent availability of statistical procedures for the identification of latent classes offers the possibility of developing SUD phenotypes integrating these developmental features. This article illustrates the utilization of SAS-TRAJ mixture modeling to characterize variations in SUD symptom trajectories to define phenotypes. METHODS: The subjects were 332 adult males with SUDs. Their course of symptoms from early adolescence through middle adulthood was retrospectively determined. Symptom trajectories were defined by the number of DSM-IV SUD symptoms by year of age. SAS-TRAJ mixture models identified trajectory classes. Model development, evaluation, and selection using this approach are discussed. RESULTS: Among these men with SUDs, six trajectory classes were identified, including groups characterized by early-onset and severe SUD symptoms persisting into adulthood, an early-onset group similar in adolescence but improving in adulthood, and other groups with symptoms emerging later with varying degrees of severity and persistence. The SUD trajectory classes were significantly different on comorbid psychopathology, particularly childhood disruptive behavior disorders. CONCLUSION: The results present a new method for the comprehensive depiction of heterogeneity in SUD symptoms. Future studies may determine the extent to which SUDs phenotypes based on the course of symptom development inform etiology, prevention and treatment research.

Adolescent↗

PubMed2006

Diary study of substance use and unsafe sex among adolescents with substance use disorders.

PURPOSE: This study tested event-level associations between substance use and condom use, as well as potential covariates, among adolescents with substance use disorders (SUDs). METHODS: A total of 134 adolescents (age, 15-21 y), 72% with SUDs, participated in telephone diary data collection of sexual events over a 6-week period. Effects on condom use of event-level substance use, partner type, salience of costs associated with unprotected sex, and subject-level SUD and sensation-seeking were tested in random intercept logistic regression models. A total of 637 sexual events were available for analysis. RESULTS: Event-level alcohol and drug use as well as subject-level SUD and sensation-seeking were not associated with condom use in multivariate models. However, all other event-level measures were significant, including an interaction between partner type and salience of preventing acquired immune deficiency syndrome (AIDS). The importance of preventing AIDS was associated only with condom use with regular partners. Prevention of pregnancy was associated with condom use independent of partner type. CONCLUSIONS: As in other event-level studies, substance use was not related to condom use in our study. Novel results in our study showed that the salience of preventing negative outcomes is a significant predictor of condom use even in the context of event-level substance use and partner type. These results suggest that prevention efforts for substance-using youth should not focus on preventing substance use as a way to prevent unsafe sex, but should emphasize the potential costs of unsafe sex even with known partners.

Adolescent↗

PubMed2006

Analyzing milestones in smoking cessation: illustration in a nicotine patch trial in adult smokers.

Tests of addiction treatments seldom reveal where treatment exercises its effect (i.e., promoting initial abstinence, preventing lapses, and/or impeding progression from lapse to relapse). The authors illustrate analyses distinguishing effects on these milestones in a randomized trial of high-dose nicotine patch (35 mg; n = 188) versus placebo (n = 136) in adult smokers, who used electronic diaries to monitor smoking in real time during 5 weeks of treatment. High-dose patch promoted initial abstinence (hazard ratio [HR] = 1.3) and decreased the risk of lapsing among those who achieved abstinence (HR = 1.6). The biggest effect of treatment was to prevent progression to relapse among those who had lapsed (HR = 7.1). Analysis of effects by milestones may enhance understanding of cessation treatments and their mechanisms of action.

Administration, Cutaneous↗

PubMed2006

Alcohol and drug use and related disorders: An underrecognized health issue among adolescents and young adults attending sexually transmitted disease clinics.

OBJECTIVES: The objectives of this study were to describe patterns of alcohol and drug use disorders among young persons attending a public sexually transmitted disease (STD) clinic and to determine their associations with sexual risk behaviors and STDs. STUDY DESIGN: Four hundred forty-eight men and women aged 15 to 24 who were attending an urban STD clinic completed an interviewer-administered questionnaire that assessed a broad range of substance use in general and for alcohol and marijuana use disorders. RESULTS: Overall, 42.9% had an alcohol or marijuana use disorder (51.6% of males and 34.2% of females), whereas 30.6% had a confirmed STD. Participants with a substance use disorder were significantly more likely to have multiple sexual partners (odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.5-3.4), to be inconsistent condom users (OR = 3.1; 95% CI = 1.5-6.3), and to have an STD (OR = 1.7; 95% CI = 1.1-2.6). CONCLUSIONS: Among young STD clinic attendees, substance use disorders were more common than confirmed STDs. STD clinics may be an appropriate setting to screen for and address substance use disorders in young persons.

Adolescent↗

PubMed2006

Predicting risky drinking outcomes longitudinally: what kind of advance notice can we get?

This paper summarizes the proceedings of a symposium presented at the 2005 Research Society on Alcoholism meeting in Santa Barbara, California, that spans the interval from toddlerhood to early middle adulthood and addresses questions about how far ahead developmentally we can anticipate alcohol problems and related substance use disorder and how such work informs our understanding of the causes and course of alcohol problems and alcohol use disorder. The context of these questions both historically and developmentally is set by Robert Zucker in an introductory section. Next, Maria Wong and colleagues describe the developmental trajectories of behavioral and affective control from preschool to early adolescence in a high risk for alcoholism longitudinal study and demonstrate their ability to predict alcohol and drug outcomes in adolescence. Duncan Clark and Jack Cornelius follow with a report on the predictive utility of parental disruptive behavior disorders in predicting onset of alcohol problems in their adolescent offspring in late adolescence. Next, Kenneth Leonard and Gregory Homish report on adult development study findings relating baseline individual, spouse, and peer network drinking indicators at marriage onset that distinguish different patterns of stability and change in alcohol problems over the first 2 years of marriage. In the final paper, John Schulenberg and colleagues, utilizing national panel data from the Monitoring the Future Study, which cover the 18- to 35-year age span, show how trajectories of alcohol use in early adulthood predict differential alcohol abuse and dependence outcomes at age 35. Finally, Robert Zucker examines the degree to which the core symposium questions are answered and comments on next step research and clinical practice changes that are called for by these findings.

Adolescent↗

PubMed2006

Predictors of marijuana use in adolescents before and after licit drug use: examination of the gateway hypothesis.

OBJECTIVE: The authors investigated whether the transition from licit drug use to marijuana use is determined by particular risk factors, as specified by the gateway hypothesis. They also evaluated the accuracy of the "gateway sequence" (illicit drug use following licit drugs) for predicting a diagnosis of substance use disorder. METHOD: Boys who consumed licit drugs only (N=99), boys who consumed licit drugs and then transitioned to marijuana use (gateway sequence) (N=97), and boys who used marijuana before using licit substances (alternative sequence) (N=28) were prospectively studied from ages 10-12 years through 22 years to determine whether specific factors were associated with each drug use pattern. The groups were compared on 35 variables measuring psychological, family, peer, school, and neighborhood characteristics. In addition, the utility of the gateway and alternative sequences in predicting substance use disorder was compared to assess their clinical informativeness. RESULTS: Twenty-eight (22.4%) of the participants who used marijuana did not exhibit the gateway sequence, thereby demonstrating that this pattern is not invariant in drug-using youths. Among youths who did exhibit the gateway pattern, only delinquency was more strongly related to marijuana use than licit drug use. Specific risk factors associated with transition from licit to illicit drugs were not revealed. The alternative sequence had the same accuracy for predicting substance use disorder as the gateway sequence. CONCLUSIONS: Proneness to deviancy and drug availability in the neighborhood promote marijuana use. These findings support the common liability model of substance use behavior and substance use disorder.

Adolescent↗

PubMed2005

Supervisory neglect and adolescent alcohol use disorders: effects on AUD onset and treatment outcome.

BACKGROUND: While parental supervision has been demonstrated to influence adolescent alcohol involvement, lack of a threshold defining inadequate supervision and little study of DSM defined alcohol use disorders (AUDs) have limited clinical applications. Utilizing a four-item supervision scale, this study identified adolescents with inadequate supervision, and examined effects on AUD development and treatment outcome. METHODS: Two groups of adolescent subjects (ages 14-17) were recruited: (1) a representative community sample of adolescents (n = 170) and (2) adolescents with AUDs from drug and alcohol or psychiatric treatment programs (n = 194). Supervision was determined by the adolescent's responses to items inquiring whether parents typically had knowledge of the adolescent's activities away from home, including with whom, where, when, and communication items. Adolescents with unusually low parental supervision (i.e., Supervisory Neglect) were identified by scale distributions. Follow-up assessments were conducted 1, 3, and 5 years after the initial assessment. RESULTS: Among community subjects, adolescents with inadequate supervision were significantly more likely to drink alcohol in a variety of situations, were more likely to have AUDs at the initial assessment and, among those without AUDs, were more likely to develop AUDs in the follow-up period. Among adolescents receiving treatment for AUDs, those with inadequate supervision were less likely to be free of AUD symptoms over a 1-year follow-up period. CONCLUSIONS: These results indicate that the described method was a straightforward and potentially clinically applicable approach to identifying adolescents with inadequate parental supervision.

Adolescent↗

PubMed2005

The drinking situations of adolescents treated for alcohol use disorders: a psychometric and alcohol-related outcomes investigation.

Psychometric properties of the Inventory of Drinking Situations (IDS) were examined using a sample of adolescents with Alcohol Use Disorders (AUDs; N = 352; mean age=16.6; 65.6% boys). Relations of drinking situations to alcohol-related outcomes 1 and 3 years following treatment also were investigated. Consistent with the higher-order structure of the IDS reported in adult samples, findings indicated that a 3 factor solution provided the best fit to the data: Negative (alpha = .98), Social (alpha = .95), and Temptation (alpha = .84) Situations. With regard to convergent and discriminate validity, evidence suggested that the Negative Situations subscale was related more strongly to an indicator of negative emotionality than to an indicator behavioral undercontrol. Conversely, the Social Situations subscale was associated more strongly with an indicator of behavioral undercontrol than an indicator of negative emotionality. Social and temptation drinking situations were associated with alcohol-related outcomes 1 year following treatment, but this was generally not the case 3 years following treatment. These results indicate that the IDS is a reliable and valid measure for use with adolescents receiving treatment for alcohol-related problems.

Adolescent↗

PubMed2005

Acute phase and five-year follow-up study of fluoxetine in adolescents with major depression and a comorbid substance use disorder: a review.

This paper reviews the results of an acute phase trial and a five-year follow-up study of fluoxetine in adolescents with major depression and a substance use disorder (SUD). This study included a 12-week open label acute phase study of 13 comorbid adolescents, followed by comprehensive assessments conducted 1, 3, and 5 years after entry into an acute phase fluoxetine trial. The results of the acute phase study and of the 1, 3, and 5-year follow-up assessments have already been published in four papers. The current paper was designed to cover the results of the study across the entire 5-year time spectrum of the study, and to summarize the clinical results across that entire time period. The data from this pilot study suggest that the long-term (5-year) clinical course for the Alcohol Dependence, Cannabis Dependence, and academic functioning of comorbid adolescents following acute phase treatment with SSRIs is generally good. However, the long-term clinical course for the Major Depression of that comorbid adolescent population is surprisingly poor.

Adolescent↗

PubMed2005

Adolescent alcohol use disorders predict adult borderline personality.

BACKGROUND: This study investigated adolescent alcohol use disorders (AUDs) and other characteristics as predictors of adult borderline personality disorder (BPD) symptoms. METHODS: Adolescents with AUDs (n = 355) were recruited from clinical treatment sources and adolescents without AUDs (n = 169) were recruited from the community. During an adolescent assessment (age 16+/-1.3), childhood physical and/or sexual abuse history, AUDs and associated psychiatric disorders were measured via semi-structured interviews. Symptoms of BPD were measured in a young adult follow-up assessment (age 22+/-2.4). Latent class analysis was utilized to classify individuals into four categories based upon BPD symptom profiles. RESULTS: Multinomial regression models indicated that adolescent AUDs and other psychiatric disorders mediated the relationship between child physical and/or sexual abuse and adult BPD latent class. CONCLUSIONS: Results were consistent with a developmental conceptualization of BPD, with AUDs and other adolescent psychopathology antecedents representing developmentally relevant forms of dysregulation, and in their more severe forms culminating in borderline symptomatology.

Adolescent↗

PubMed2005

Multidimensional assessment of nicotine dependence in adolescents.

Despite the critical importance of adolescent smoking, the assessment of nicotine dependence during this developmental period has been the subject of relatively little research. In this study, 301 adolescents (ages 12 through 18 years) reporting daily smoking were recruited for a project on alcohol use disorders (AUDs). The sample included 140 females and 161 males, 251 subjects from clinical and 50 from community sources, and 176 subjects with AUDs at the baseline assessment. Subjects were evaluated with the Nicotine Dependence Syndrome Scale (NDSS), the Fagerstrom Test for Nicotine Dependence (FTND) and a determination of average number of cigarettes per day (cigarettes/day). A varimax factor analysis of 27 NDSS items revealed four factors: (1) Drive/Tolerance (13 items; Cronbach alpha = 0.91); (2) Continuity (five items; Cronbach alpha = 0.67); (3) Priority (three items; Cronbach alpha = 0.64); (4) Stereotypy (five items; Cronbach alpha = 0.66). The NDSS total score, refined by the removal of four items, was also examined (23 items; Cronbach alpha = 0.90). Predicting cigarettes/day at follow-up, initial smoking rate was the best predictor, with the FTND and NDSS Total score showing significant and similar predictive validity. The NDSS Total showed incremental validity in the prediction of smoking progression in a model including demographic characteristics, initial smoking rate and FTND. The findings suggest that the NDSS has acceptable psychometric properties when applied to adolescents, complementing smoking rate and FTND in a multidimensional smoking assessment.

Adolescent↗

PubMed2005

Childhood risk categories for adolescent substance involvement: a general liability typology.

Childhood risks for adolescent substance involvement include parental substance use disorders (SUDs), psychological dysregulation and early tobacco and alcohol experimentation. This study was designed to identify childhood risk categories predicting accelerated adolescent substance involvement across drug types and stages. The index subjects were 560 children recruited from high risk (n = 266) or low risk (n = 294) families based on fathers' SUDs. Assessments were conducted at approximately ages 11 (baseline), 13, 16, and 19 years. Childhood predictors included parent SUDs, early tobacco or alcohol use (i.e., substance use), and neurobehavior disinhibition (ND) as determined by indicators of cognitive, affective and behavioral disinhibition. A cluster analysis defined five risk categories based on baseline characteristics as follows: (1) High (n = 31; 100% had both parents with SUDs, 100% had early substance use, and the mean ND score = 58.9); (2) Intermediate-High (n = 76; 45% had one parent with SUD, 100% early substance use and ND = 51.9); (3) Intermediate (n = 76; 100% both parents with SUDs, 0% early substance use and ND = 51.4); (4) Intermediate-Low (n = 161; 100% with one SUD parent; 0% early substance use and ND = 49.9) and; (5) Low (n = 216; no parental SUD, no early substance use and ND = 47.5). Compared with all other groups, children in the High risk group had significantly accelerated substance involvement across all substance types and stages. The ordering of risk categories from low to high was also consistent for all substance involvement outcomes. The findings indicate that these five risk categories constitute general liability classes for adolescent substance involvement, and may identify homogeneous groups of children requiring distinct preventive interventions.

Adolescent↗

PubMed2005

Treatment of co-occurring alcohol, drug, and psychiatric disorders.

Comorbid psychiatric disorders and drug use disorders (DUDs) are common among adolescents with alcohol use disorders (AUDs). These comorbid disorders have a large potential significance on the clinical course of the AUDs among adolescents, and can predict a shorter time to relapse of alcohol use. The use of medication for treatment of the various comorbid adolescent populations has increased dramatically in recent years, despite the lack of double-blind, placebo-controlled studies that demonstrate their safety and efficacy. Consequently, to date, no empirically proven treatment exists for most of these comorbid disorders. This chapter reviews the state of the art regarding the treatment of comorbid adolescents. This chapter also identifies gaps in knowledge regarding the treatment of comorbid adolescents, and outlines directions for future research in this field.

Adolescent↗

PubMed2005

Fluoxetine in adolescents with comorbid major depression and an alcohol use disorder: a 3-year follow-up study.

The goal of this 3-year follow-up evaluation was to determine whether the decreases in drinking and in depressive symptoms that were noted during our acute phase study with fluoxetine in comorbid adolescents persisted at a 3-year follow-up evaluation. At the 3-year follow-up evaluation, the group continued to demonstrate significantly fewer DSM criteria for an AUD and fewer BDI depressive symptoms and also consumed fewer standard drinks than they had demonstrated at the baseline of the acute phase study. However, 7 of the 10 participants demonstrated MDD at the 3-year follow-up assessment, and 4 demonstrated an AUD. The presence of a MDD was significantly correlated with the presence of an AUD at both the 1-year and the 3-year follow-up assessments. Four of the participants restarted SSRI medications during the follow-up period. Half of the subjects graduated from college during the 3-year assessment period, despite their residual depressive symptoms and drinking. We conclude that the long-term therapeutic effects of an acute phase trial of fluoxetine plus psychotherapy slowly decrease but did not disappear when fluoxetine is discontinued shortly after the acute phase trial. The high rate of MDD at follow-up suggests that longer term antidepressant medication treatment may be needed for at least some comorbid adolescents.

Adolescent↗

PubMed2005

Prefrontal cortex, thalamus, and cerebellar volumes in adolescents and young adults with adolescent-onset alcohol use disorders and comorbid mental disorders.

BACKGROUND: In adults, prefrontal, thalamic, and cerebellar brain injury is associated with excessive ethanol intake. As these brain structures are actively maturing during adolescence, we hypothesized that subjects with adolescent-onset alcohol use disorders, compared with control subjects, would have smaller brain volumes in these areas. Thus, we compared prefrontal-thalamic-cerebellar measures of adolescents and young adults with adolescent-onset alcohol use disorders (AUD, defined as DSM-IV alcohol dependence or abuse) with those of sociodemographically similar control subjects. METHODS: Magnetic resonance imaging was used to measure prefrontal cortex, thalamic, and cerebellar volumes in 14 subjects (eight males, six females) with an AUD (mean age, 17.0+/-2.1 years) and 28 control subjects (16 males, 12 females; 16.9+/-2.3 years). All AUD subjects were recruited from substance abuse treatment programs and had comorbid mental disorders. RESULTS: Subjects with alcohol use disorders had smaller prefrontal cortex and prefrontal cortex white matter volumes compared with control subjects. Right, left, and total thalamic, pons/brainstem, right and left cerebellar hemispheric, total cerebellar, and cerebellar vermis volumes did not differ between groups. There was a significant sex-by-group effect, indicating that males with an adolescent-onset AUD compared with control males had smaller cerebellar volumes, whereas the two female groups did not differ in cerebellar volumes. Prefrontal cortex volume variables significantly correlated with measures of alcohol consumption. CONCLUSIONS: These findings suggest that a smaller prefrontal cortex is associated with early-onset drinking in individuals with comorbid mental disorders. Further studies are warranted to examine if a smaller prefrontal cortex represents a vulnerability to, or a consequence of, early-onset drinking.

Adolescent↗