Mediating pathways from childhood ADHD to adolescent tobacco and marijuana problems: roles of peer impairment, internalizing, adolescent ADHD symptoms, and gender.

BACKGROUND: We examined whether increased risk for adolescent tobacco and marijuana problems associated with childhood ADHD is explained by key intermediary influences during adolescence and differs by gender. METHODS: Longitudinal structural equation models examined mediating effects on problems with both substances (or each substance separately) through age-14 peer impairment, internalizing, and adolescent ADHD symptoms in two twin samples, prospectively assessed since age 11 (N = 2,164). Whether these mediators contributed beyond mediating effects of early-adolescent substance use was also considered. Twin difference analyses further illuminated which mediators might be potentially causal. RESULTS: Direct effects of childhood ADHD on age-17 tobacco and marijuana problems (i.e., independent of included mediators) as well as effects of adolescent ADHD symptoms were significant only for females. By contrast, mediation by peer impairment, evident particularly for marijuana, was relatively stronger for males than females. Depression and anxiety were not prospectively associated with age-17 substance problems when earlier substance problems were considered. Consistent with causal influence of early substance use on later problems, monozygotic twins with more severe tobacco or marijuana problems at age 14 than their co-twins were also more likely to have substance problems later in adolescence. CONCLUSIONS: Mediation through peer impairment, continued presence of ADHD symptoms, and early substance use may alter development so that childhood ADHD indirectly contributes to problems with tobacco and marijuana. Targeting gender-sensitive interventions prior to mid-adolescence, before these patterns become established, is essential.

The role of parental marital discord in the etiology of externalizing problems during childhood and adolescence.

Previous research has established that parental marital discord is associated with higher levels of offspring externalizing behaviors, but it is unclear how parental relationship functioning is associated with the genetic and environmental variance on a factor of externalizing problems. Thus, the current study assessed how parental marital discord moderates genetic and environmental variance on offspring externalizing problems at two different ages: childhood and late adolescence. That is, the magnitude of genetic and environmental influences on offspring externalizing at ages 11 and 17 was examined as a function of parental marital discord. Consistent with a diathesis-stress model of psychopathology, it was hypothesized that with increasing marital discord, genetic influences on externalizing would be more pronounced. Rather, results indicated that for the 11-year-old sample, nonshared environmental influences were greater when parental marital discord was low, and comparatively, shared environmental influences contributed more to the variance in externalizing problems when parental marital discord was high. No moderation was found for the 17-year-old cohort. In contrast to studies that do not find an effect of the shared environment, these results provide evidence that the common rearing environment has an impact on externalizing problems in preadolescent children.

Romantic Relationship Satisfaction Moderates the Etiology of Adult Personality.

The heritability of major normative domains of personality is well-established, with approximately half the proportion of variance attributed to genetic differences. In the current study, we examine the possibility of gene × environment interaction (G×E) for adult personality using the environmental context of intimate romantic relationship functioning. Personality and relationship satisfaction are significantly correlated phenotypically, but to date no research has examined how the genetic and environmental components of variance for personality differ as a function of romantic relationship satisfaction. Given the importance of personality for myriad outcomes from work productivity to psychopathology, it is vital to identify variables present in adulthood that may affect the etiology of personality. In the current study, quantitative models of G×E were used to determine whether the genetic and environmental influences on personality differ as a function of relationship satisfaction. We drew from a sample of now-adult twins followed longitudinally from adolescence through age 29. All participants completed the Multidimensional Personality Questionnaire (MPQ) and an abbreviated version of the Dyadic Adjustment Scale. Biometric moderation was found for eight of the eleven MPQ scales examined: well-being, social potency, negative emotionality, alienation, aggression, constraint, traditionalism, and absorption. The pattern of findings differed, suggesting that the ways in which relationship quality moderates the etiology of personality may depend on the personality trait.

The impact of attention-deficit/hyperactivity disorder on preadolescent adjustment may be greater for girls than for boys.

Whether gender differences exist in the impairment associated with attention-deficit/hyperactivity disorder (ADHD) is still largely unknown, because most samples have few affected girls or include only one sex. The current study evaluated whether ADHD affects adjustment differently for girls than boys in a population-based cohort of 11-year-olds (520 girls, 478 boys). Those with a DSM-IV diagnosis of ADHD (predominantly inattentive, hyperactive-impulsive, or combined) were compared to those without ADHD on teacher, parent, and child reports of academics, peer relationships, self-concept, clinical symptoms, and treatment. Although boys and girls with ADHD experienced difficulties in all areas, girls with ADHD, especially the inattentive subtype, were more negatively affected in academics and peer relationships. Inattentive girls were less popular and more likely to be bullied than girls without ADHD, whereas inattentive boys were not. The social isolation experienced by many girls with ADHD deserves greater attention.

Associations Between Common Forms of Psychopathology and Fecundity: Evidence From a Prospective, Longitudinal Twin Study.

We examined associations between common psychiatric disorders and fecundity in a population-based cohort of 1252 twins prospectively assessed from adolescence into adulthood. Major depressive, anxiety, and alcohol use disorders were associated with lower likelihood of having children and having fewer children. Survival analyses yielded similar results accounting for timing/recurrence. Although both early- and adult-onset psychiatric disorders were associated with decreased fecundity, early-onset major depressive, anxiety (among boys), and alcohol use disorders (among girls) were associated with greater likelihood of having a child during adolescence. Among twin pairs discordant for psychiatric disorders, twins affected by anxiety and alcohol use, but not major depressive, disorders were less likely to have children than unaffected co-twins. However, unaffected twins with an affected co-twin were no more likely to have children than twins from unaffected twin pairs, inconsistent with the balancing selection hypothesis that increased fecundity in unaffected relatives accounts for persistence of psychiatric disorders.

Where Do Gambling Problems Fit in the Structure of Psychopathology During Emerging Adulthood?

Research suggests major mental disorders co-occur at higher than chance levels. In adult samples, a two factor structure emerges when modeling the higher order structure of psychopathology. Specifically, disorders tend to co-aggregate into two dimensions: Internalizing (depression and anxiety) and Externalizing (acting out, impulsive, and addictive) disorders. Despite this large body of evidence, few studies have integrated problem gambling into this overall model. We used confirmatory factor analysis to model how the symptom count of gambling fits into the structure of psychopathology in a large, community based young adult twin sample of men and women (age 24; N=1329). Twins were assessed via in-person, structured diagnostic interviews on disorders including: Major Depression, Phobias, Post-Traumatic Stress Disorder and Anxiety Disorders (internalizing) and Substance Use Disorders, Gambling Problems (self-report), and Antisocial Behaviors (externalizing). The data were fit to a two-factor structure, with gambling symptoms loading most highly on externalizing, rather than internalizing. The problem gambling loadings did not differ by sex. Implications of these findings suggest that during emerging adulthood gambling problems are best classified and conceptualized in the realm of externalizing disorders for both males and females. Results also suggest prevention and intervention efforts be aimed at young adults who exhibit commonly co-occurring psychopathology.

Differential implications of persistent, remitted, and late-onset ADHD symptoms for substance abuse in women and men: A twin study from ages 11 to 24.

BACKGROUND: Persistence and emergence of ADHD in adulthood are associated with substance problems. We investigate differential implications of ADHD course for tobacco, alcohol, or marijuana problems by sex, then whether substance misuse results from ADHD or contributes to it, through a twin differences design. METHODS: A population-based cohort of 998 twins (61 % monozygotic; 52 % female), born in Minnesota from 1988 to 1994, was prospectively assessed from ages 11-24. Childhood ADHD was oversampled. At age 24, 255 had a history of childhood-onset ADHD (160 persistent, 95 remitted); 93 had late-onset ADHD symptoms identified in late-adolescence/adulthood. Persistent, remitted, and late-onset groups were compared to those without ADHD (N = 459) on childhood characteristics and age-24 substance problems. RESULTS: Persistent and late-onset groups differed in childhood; twin concordances suggested greater genetic etiology for persistent ADHD. As adolescents, however, both groups were high in conduct problems; by adulthood, they were comparably high in substance problems. In particular, women whose ADHD persisted were 5 times more likely to develop tobacco use disorder than women without ADHD. Remitted ADHD was associated with less-increased risk, except for alcohol problems among women. Consistent with possible causality, monozygotic female twins with more age-17 ADHD symptoms than co-twins had more age-24 tobacco symptoms; a similar association was found for alcohol. CONCLUSIONS: Presence or emergence of ADHD in early adulthood increases substance problems to a greater degree for women than men. While effects of substances on later ADHD were not statistically significant, detection was limited by the relative rarity of late-adolescent substance symptoms.

The enrichment study of the Minnesota twin family study: increasing the yield of twin families at high risk for externalizing psychopathology.

The Enrichment Study (ES) was designed to extend the Minnesota Twin Family Study (MTFS) by oversampling 11-year-old twins at especially high risk for substance use disorders by virtue of having a childhood disruptive disorder. The sample was ascertained from Minnesota birth records. To identify high-risk twins, we conducted telephone screening interviews for parent-reported symptoms of attention-deficit/hyperactivity disorder (ADHD) and conduct disorder (CD) as well as indications of academic disengagement. Twins who exceeded a predetermined threshold were invited to participate. To facilitate comparison with the previously ascertained MTFS participants, a random sample of 11-year-old twins was also recruited. As part of the ES study, 499 twin pairs, and their parents, visited the University of Minnesota, where each participant completed a clinical interview, psychophysiological evaluation, and thorough assessment of environmental risk. We were highly successful in recruiting at-risk twins; 52% of the screened male twins and 41% of the screened females met criteria for a diagnosis of ADHD, CD, or oppositional defiant disorder (ODD). At the pair level, 63% of the screened pairs had at least one member with a childhood disruptive disorder. This article provides an overview of the study design and includes a review of recent findings using this sample of twins.

Prospective effects of attention-deficit/hyperactivity disorder, conduct disorder, and sex on adolescent substance use and abuse.

CONTEXT: Attention-deficit/hyperactivity disorder (ADHD), an early manifestation of externalizing behavior, may identify children at high risk for later substance abuse. However, the ADHD-substance abuse relationship often disappears when co-occurring conduct disorder (CD) is considered. OBJECTIVE: To determine whether there is a prospective relationship between ADHD and the initiation of substance use and disorders, and whether this relationship depends on the ADHD subtype (hyperactive/impulsive or inattentive), CD, or sex. DESIGN, SETTING, AND PARTICIPANTS: Dimensional and categorical measures of ADHD and CD were examined via logistic regression analyses in relation to subsequent initiation of tobacco, alcohol, and illicit drug use by 14 years of age and onset of substance use disorders by 18 years of age in a population-based sample of 11-year-old twins (760 female and 752 male twins) from the Minnesota Twin Family Study. MAIN OUTCOME MEASURES: Structured interviews were administered to adolescents and their mothers regarding substance use and to generate diagnoses. RESULTS: For boys and girls, hyperactivity/impulsivity predicted initiation of all types of substance use, nicotine dependence, and cannabis abuse/dependence (for all, P < .05), even when controlling for CD at 2 time points. By contrast, relationships between inattention and substance outcomes disappeared when hyperactivity/impulsivity and CD were controlled for, with the possible exception of nicotine dependence. A categorical diagnosis of ADHD significantly predicted tobacco and illicit drug use only (adjusted odds ratios, 2.01 and 2.82, respectively). A diagnosis of CD between 11 and 14 years of age was a powerful predictor of substance disorders by 18 years of age (all odds ratios, > 4.27). CONCLUSIONS: Hyperactivity/impulsivity predicts later substance problems, even after growth in later-emerging CD is considered, whereas inattention alone poses less risk. Even a single symptom of ADHD or CD is associated with increased risk. Failure in previous research to consistently observe relationships between ADHD and substance use and abuse outcomes could be due to reliance on less-sensitive categorical diagnoses.

The relationship between subjective well-being and mortality within discordant twin pairs from two independent samples.

Prior research has shown robust associations between greater subjective well-being (SWB) and reduced mortality. Whether this observed association is causal in nature or due instead to confounding genetic or environmental factors affecting both SWB and mortality is not well understood. We used a combined sample of 6,802 twins drawn from two cohorts: the Longitudinal Study of Middle-Aged Danish Twins (MADT; N = 2,815, baseline age between 45 and 69 years, M = 56.8, SD = 6.4) and the Longitudinal Study of Aging Danish Twins (LSADT; N = 3,987, baseline age between 70 and 97 years, M = 76.6, SD = 4.9). The relationship between SWB, encompassing measures of life satisfaction and affect, and all-cause mortality was evaluated using survival analyses at both the individual level and within twin pairs. Twin difference analyses were completed within 1,053 monozygotic (MZ) twin pairs and 1,143 dizygotic (DZ) twin pairs to control for genetic and shared environmental confounding. As expected, the individual-level results showed that higher levels of SWB were associated with reduced mortality: affect hazard ratio (HR) = .90, 95% confidence interval (CI) [.87, .94]; life satisfaction HR = .88, 95% CI [.84, .92]. The effect of SWB on reduced mortality remained significant within both MZ and DZ pairs, suggesting that the association is independent of genetic and nonshared environmental confounding factors. These findings, which generalized across both younger (MADT) and older (LSADT) cohorts of adults, remained significant when accounting for demographic factors, physical health, and cognitive functioning. (PsycINFO Database Record

Maladaptive personality traits and romantic relationship satisfaction: A monozygotic co-twin control analysis.

The recent inclusion of an alternative model for personality disorders in the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5; American Psychiatric Association, 2013a) highlights the importance of extreme variants of personality for psychopathology. The maladaptive personality traits described in the alternative model comprise 5 higher-order domains and 25 lower-order facets that capture pathological levels of personality. The present report adds to a growing body of research on the implications of maladaptive personality traits for functioning by demonstrating significant associations between each of the higher-order domains (Negative Affect, Detachment, Antagonism, Disinhibition, and Psychoticism) and most of the lower-order facets and lower romantic relationship satisfaction in a population-based sample of 284 monozygotic (MZ) adult twins. We further capitalized upon co-twin differences in levels of personality pathology in a causally informative approach, the MZ co-twin control study design. Co-twin control analyses indicated that higher levels of Negative Affect, Detachment, Disinhibition, and Psychoticism, as well as several lower-order facets, were associated with lower romantic relationship satisfaction even after accounting for the genetic and environmental factors shared by twins that confer liability toward personality pathology and psychosocial dysfunction. The present results lend support to the potentially causal implications of personality pathology for interpersonal functioning, even in a community sample unlikely to be evidencing clinical levels of pathology, by suggesting that extreme variants of personality, manifested by comparably extreme deviations in thinking, feeling, behaving, and interacting with others, may lead to impaired functioning in important domains. (PsycINFO Database Record

Associations between childhood ADHD, gender, and adolescent alcohol and marijuana involvement: A causally informative design.

BACKGROUND: We report whether the etiology underlying associations of childhood ADHD with adolescent alcohol and marijuana involvement is consistent with causal relationships or shared predispositions, and whether it differs by gender. METHODS: In three population-based twin samples (N = 3762; 64% monozygotic), including one oversampling females with ADHD, regressions were conducted with childhood inattentive or hyperactive-impulsive symptoms predicting alcohol and marijuana outcomes by age 17. To determine whether ADHD effects were consistent with causality, twin difference analyses divided effects into those shared between twins in the pair and those differing within pairs. RESULTS: Adolescents with more severe childhood ADHD were more likely to initiate alcohol and marijuana use earlier, escalate to frequent or heavy use, and develop symptoms. While risks were similar across genders, females with more hyperactivity-impulsivity had higher alcohol consumption and progressed further toward daily marijuana use than did males. Monozygotic twins with more severe ADHD than their co-twins did not differ significantly on alcohol or marijuana outcomes, however, suggesting a non-causal relationship. When co-occurring use of other substances and conduct/oppositional defiant disorders were considered, hyperactivity-impulsivity remained significantly associated with both substances, as did inattention with marijuana, but not alcohol. CONCLUSIONS: Childhood ADHD predicts when alcohol and marijuana use are initiated and how quickly use escalates. Shared familial environment and genetics, rather than causal influences, primarily account for these associations. Stronger relationships between hyperactivity-impulsivity and heavy drinking/frequent marijuana use among adolescent females than males, as well as the greater salience of inattention for marijuana, merit further investigation.

Increased Risk of Smoking in Female Adolescents Who Had Childhood ADHD.

OBJECTIVE: This study examined the effects of childhood attention deficit hyperactivity disorder (ADHD) symptoms, both inattention and hyperactivity-impulsivity, on the development of smoking in male and female adolescents. METHOD: Twin difference methods were used to control for shared genetic and environmental confounders in three population-based, same-sex twin samples (N=3,762; 64% monozygotic). One cohort oversampled female adolescents with ADHD beginning in childhood. Regressions of childhood inattentive and hyperactive-impulsive symptoms were conducted to predict smoking outcomes by age 17. ADHD effects were divided into those shared between twins in the pair and those nonshared, or different within pairs. RESULTS: Adolescents who had more severe ADHD symptoms as children were more likely to initiate smoking and to start smoking younger. The association of ADHD symptoms with daily smoking, number of cigarettes per day, and nicotine dependence was greater in females than in males. Monozygotic female twins with greater attentional problems than their co-twins had greater nicotine involvement, consistent with possible causal influence. These effects remained when co-occurring externalizing behaviors and stimulant medication were considered. Hyperactivity-impulsivity, while also more strongly related to smoking for female adolescents, appeared primarily noncausal. CONCLUSIONS: Smoking initiation and escalation are affected differentially by ADHD subtype and gender. The association of inattention with smoking in female adolescents may be causal, whereas hyperactivity-impulsivity appears to act indirectly, through shared propensities for both ADHD and smoking.

Parent-Offspring Resemblance for Drinking Behaviors in a Longitudinal Twin Sample.

OBJECTIVE: The purpose of the current study was to evaluate parent-offspring resemblance for alcohol consumption and dependence symptoms, including sex-specific effects, and how these patterns change across adolescence and early adulthood. METHOD: Three cohorts of twins were assessed longitudinally at five time points between ages 14 and 29 years, with parents directly assessed at intake, using structured interviews. Twin offspring and parents from the population-based Minnesota Twin Family Study were included for a total sample size of 3,762 offspring (52% female) and their parents. Alcohol use was measured using an index based on drinking quantity, frequency, maximum drinks, and number of intoxications. Alcohol dependence symptom counts were also used. RESULTS: Parent-offspring correlations for alcohol consumption increased from age 14 (r = .12) to age 17 (r = .25), remained stable from ages 17 through 24, and then decreased slightly by age 29 (r = .19). Familial resemblance for symptoms of alcohol dependence peaked at age 17 (r = .18) then decreased through age 29 (r = .11). Parent-offspring correlations of both measures did not vary significantly by sex of offspring or sex of parent. CONCLUSIONS: Overall, parent-offspring resemblance for alcohol use and problems is relatively stable after early adulthood, with resemblance for alcohol use at higher magnitudes across offspring development. Evidence for differential resemblance based on sex of offspring or parents was lacking.

Personality traits and the development of nicotine, alcohol, and illicit drug disorders: prospective links from adolescence to young adulthood.

The personality traits constraint (CN) and negative emotionality (NE) have been more (CN) or less (NE) consistently associated with alcoholism. The authors examined the association of personality at age 17 with timing of onset and with prospective prediction of nicotine, alcohol, and illicit drug disorders 3 years later in a twin sample (569 females; 432 males). Earlier onset of alcohol and drug disorders (by age 17) was related to significantly lower CN compared with later onsets (by age 20); high NE was related to either onset. NE, as well as CN, uniquely predicted new onsets of all 3 types of substance use disorders by follow-up, with preexisting substance disorders taken into account. Personality traits confer generalized risk for developing any substance disorder, though some traits are more strongly linked with some substance disorders than with others.

High School Sports Involvement Diminishes the Association Between Childhood Conduct Disorder and Adult Antisocial Behavior.

PURPOSE: Life course-persistent antisocial behavior manifests as a display of aggressive and antisocial behavior beginning in childhood (conduct disorder [CD]) and lasting through adulthood (adult antisocial personality disorder). This study aimed to build on prior research by evaluating whether involvement in high school sports helped attenuate the association between CD and subsequent adult antisocial behavior (AAB). METHODS: A prospective sample of 967 male and female adolescents (56% adopted) was used. Structured interviews were used to assess CD (symptoms before the age of 15 years), involvement in sports during high school, and past-year adult antisocial personality disorder symptoms in young adulthood (M age = 22.4 years). RESULTS: As expected, the association between CD and AAB was significantly less for those involved in sports (ß = .28; p < .001) compared with those not involved in sports (ß = .49; p < .001), χ(2)(1) = 4.13; p = .04. This difference remained after including known covariates of antisocial behavior in the model (age, gender, adoption status), and results were consistent across males and females. Involvement in other extracurricular activities (e.g., student government, plays, clubs) did not significantly moderate the relationship between CD and AAB. CONCLUSIONS: Although selection effects were evident (those with more CD symptoms were less likely to be involved in sports), findings nevertheless suggest high school sports involvement may be a notable factor related to disrupting persistent antisocial behavior beginning in childhood and adolescence and lasting through young adulthood. Implications are discussed.

The effect of parental alcohol and drug disorders on adolescent personality.

OBJECTIVE: The relationship of parental alcohol or drug diagnosis to offspring personality was examined in a population-based sample of 17-year-old twins (568 girls and 479 boys) participating in the Minnesota Twin Family Study. Whether offspring personality characteristics 1) are specific to the type of substance use disorder in parents (alcohol versus drug) and 2) are found in high-risk offspring without substance use disorders as well as in offspring with substance use disorders was investigated. METHOD: Personality was assessed with the Multidimensional Personality Questionnaire; substance use disorders were assessed in person through diagnostic interviews. RESULTS: In both male and female offspring, parental history of alcohol dependence was associated with greater negative emotionality, aggression, stress reaction, and alienation but lower well-being; parental history of drug disorders was associated with lower constraint, control, harm avoidance, and traditionalism but higher social potency. Excluding offspring with a substance use disorder had virtually no effect on the statistical significance of these findings. CONCLUSIONS: In contrast to findings in some adult samples, personality characteristics associated with a family history of substance use disorders are found even in adolescent offspring who have not yet developed these disorders themselves, suggesting that personality might be one indicator of familial risk for substance use disorders during this developmental stage. Personality profiles of offspring of parents with substance use disorders also show some diagnostic specificity, with constraint associated with parental drug abuse and negative emotionality with parental alcoholism.

The mental health of US adolescents adopted in infancy.

OBJECTIVE: To determine whether adopted adolescents are at excess risk for clinically relevant behavioral and emotional problems. DESIGN: We examined whether adopted and nonadopted adolescents differed on quantitative indicators of mental health and the prevalence of childhood disorders and whether differences exist between internationally and domestically placed adoptees. SETTING: Assessments occurred at the University of Minnesota from December 11, 1998, to June 4, 2004. PARTICIPANTS: Adolescents adopted in infancy were systematically ascertained from records of 3 large Minnesota adoption agencies; nonadopted adolescents were ascertained from Minnesota birth records. The final sample included these adolescents with their rearing parents. Main Exposure The main exposure was adoptive status: nonadopted (n = 540), international adoptive placement (n = 514), or domestic adoptive placement (n = 178). OUTCOME MEASURES: Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) clinical assessments based on child and parent reports of attention-deficit/hyperactivity, oppositional defiant, conduct, major depressive, and separation anxiety disorders; teacher reports of psychological health; and contact with mental health professionals. RESULTS: Adoptees scored only moderately higher than nonadoptees on quantitative measures of mental health. Nevertheless, being adopted approximately doubled the odds of having contact with a mental health professional (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.48-2.84) and of having a disruptive behavior disorder (OR, 2.34; 95% CI, 1.72-3.19). Relative to international adoptees, domestic adoptees had higher odds of having an externalizing disorder (OR, 2.60; 95% CI, 1.67-4.04). CONCLUSIONS: Moderate mean differences in quantitative indicators of mental health can lead to substantial differences in disorder prevalence. Although most adopted adolescents are psychologically healthy, they may be at elevated risk for some externalizing disorders, especially among those domestically placed.