Personality Dimensions as Common and Broadband-Specific Features for Internalizing and Externalizing Disorders

Several researchers have suggested that the nature of the covariation between internalizing and externalizing disorders may be understood better by examining the associations between temperament or personality and these disorders. The present study examined neuroticism as a potential common feature underlying both internalizing and externalizing disorders and novelty seeking as a potential broad-band specific feature influencing externalizing disorders alone. Participants were 12- to 18-year-old twin pairs (635 monozygotic twin pairs and 691 dizygotic twin pairs; 48 % male and 52 % female) recruited from the Colorado Center for Antisocial Drug Dependence. Genetic and nonshared environmental influences shared in common with neuroticism influenced the covariation among distinct internalizing disorders, the covariation among distinct externalizing disorders, and the covariation between internalizing and externalizing disorders. Genetic influences shared in common with novelty seeking influenced the covariation among externalizing disorders and the covariation between major depressive disorder and externalizing disorders, but not the covariation among internalizing disorders or between anxiety disorders and externalizing disorders. Also, after accounting for genetic and environmental influences shared in common with neuroticism and novelty seeking, there were no significant common genetic or environmental influences among the disorders examined, suggesting that the covariance among the disorders is sufficiently explained by neuroticism and novelty seeking. We conclude that neuroticism is a heritable common feature of both internalizing disorders and externalizing disorders, and that novelty seeking is a heritable broad-band specific factor that distinguishes anxiety disorders from externalizing disorders.     

Structure and Etiology of Co-occurring Internalizing and Externalizing Disorders in Adolescents

Several studies suggest that a two-factor model positing internalizing and externalizing factors explains the interrelationships among psychiatric disorders. However, it is unclear whether the covariation between internalizing and externalizing disorders is due to common genetic or environmental influences. We examined whether a model positing two latent factors, internalizing and externalizing, explained the interrelationships among six psychiatric disorders (major depressive disorder, generalized anxiety disorder, separation anxiety disorder, attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder) in adolescents, and whether there are common genetic and environmental influences on internalizing and externalizing latent factors. Multivariate behavior genetic analyses of data from 1162 twin pairs and 426 siblings ascertained from the general population via the Colorado Center for Antisocial Drug Dependence (CADD) were conducted. We found support for a model positing two latent factors (internalizing and externalizing). These factors were moderately heritable and influenced by significant common genetic and nonshared environmental influences. These findings suggest that co-occurrence of internalizing and externalizing psychopathology in adolescents results from both genetic and environmental influences.     

A Common Genetic Factor Explains the Covariation Among ADHD ODD and CD Symptoms in 9–10 Year Old Boys and Girls

Previous studies examining the covariation among Attention Deficit Hyperactivity Disorder (ADHD), Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD) have yielded inconsistent results. Some studies have concluded that the covariation among these symptoms is due to common genetic influences, whereas others have found a common environmental overlap. The present study investigated the genetic and environmental correlations among these three childhood disorders, based on a sample of 1,219 twins, age 9–10 years. A latent externalizing behavior factor was found to explain the covariance among ADHD, ODD and CD symptoms. Genetic influences explained more than half of the variance in this externalizing factor in both boys and girls. There were also unique genetic and environmental influences in each set of symptoms, suggesting some etiological independence of the three disorders. Our findings have implications for molecular genetic studies trying to identify susceptibility genes for these disorders. This study was funded by NIMH (R01 MH58354). Catherine Tuvblad was supported by post-doctoral stipends from the Swedish Council for Working Life and Social Research (Project 2006-1501) and the Sweden-America Foundation. Adrian Raine was supported by NIMH (Independent Scientist Award K02 MH01114-08). We thank the Southern California Twin Project staff for their assistance in collecting data, and the twins and their families for their participation.     

Understanding the Covariation Among Childhood Externalizing Symptoms: Genetic and Environmental Influences on Conduct Disorder,Attention Deficit Hyperactivity Disorder,and Oppositional Defiant Disorder Symptoms

Conduct disorder (CD), attention deficit hyperactivity disorder (ADHD), and oppositional defiant disorder (ODD) are common childhood externalizing disorders that frequently co-occur. However, the causes of their comorbidity are not well understood. To address that question, we analyzed data from > 600 Finnish twin pairs, who completed standardized interviews at age 14. Behavior genetic methods were used to examine how genetic/environmental factors contribute to each disorders symptoms and to their covariation. We found significant genetic effects on each disorder with only modest evidence of shared environmental influences. Our data suggest the comorbidity among CD, ADHD, and ODD is primarily explained by shared genetic influences; however, each disorder was also under unique genetic influence, supporting the distinction of each disorder.     

The Association Between Internalizing and Externalizing Behavior in Childhood and Early Adolescence: Genetic or Environmental Common Influences?

This study analyzed the genetic and environmental influences on internalizing and externalizing behavior problems and the nature of their cooccurrence in a national Norwegian twin sample. The sample comprised 526 identical and 389 fraternal same-sexed twin pairs from five birth cohorts, aged 5-6, 8-9, 12-13, 13-14, and 14-15 years. Behavior problems were assessed by parental ratings on the Child Behavior Checklist. A model of additive genetic, shared, and nonshared environmental influences was fitted to both internalizing and externalizing behavior in four sex and age groups. The considerable covariance,r = .51 to .58, between these traits is accounted for mainly by common environmental components; this effect was most marked in the 5 to 9-year olds. Concordance rates for children scoring above 1 standard deviation from the total sample mean on the internalizing scale only, externalizing scale only, or both indicated stronger genetic influences for internalizing or externalizing problems only than for combined problems.     

Common Etiological Sources of Anxiety,Depression, and Somatic Complaints in Adolescents: A Multiple Rater twin Study

Somatic complaints in children and adolescents may be considered part of a broader spectrum of internalizing disorders that include anxiety and depression. Previous research on the topic has focused mainly on the relationship between anxiety and depression without investigating how common somatic symptoms relate to an underlying factor and its etiology. Based on the classical twin design with monozygotic and dizygotic twins reared together, our study aimed to explore the extent to which the covariation between three phenotypes in adolescent girls and boys can be represented by a latent internalizing factor, with a focus on both common and specific etiological sources. A population-based sample of twins aged 12–18 years and their mothers and fathers (N?=?1394 families) responded to questionnaire items measuring the three phenotypes. Informants’ ratings were collapsed using full information maximum likelihood estimated factor scores. Multivariate genetic analyses were conducted to examine the etiological structure of concurrent symptoms. The best fitting model was an ACE common pathway model without sex limitation and with one substantially heritable (44 %) latent factor shared by the phenotypes. Concurrent symptoms also resulted from shared (25 %) and non-shared (31 %) environments. The factor loaded most on depression symptoms and least on somatic complaints. Trait-specific influences explained 44 % of depression variance, 59 % of anxiety variance, and 65 % of somatic variance. Our results suggest the presence of a general internalizing factor along which somatic complaints and mental distress can be modeled. However, specific influences make the symptom types distinguishable.     

Testing Models of Psychopathology in Preschool-aged Children Using a Structured Interview-based Assessment

A number of studies have found that broadband internalizing and externalizing factors provide a parsimonious framework for understanding the structure of psychopathology across childhood, adolescence, and adulthood. However, few of these studies have examined psychopathology in young children, and several recent studies have found support for alternative models, including a bi-factor model with common and specific factors. The present study used parents’ (typically mothers’) reports on a diagnostic interview in a community sample of 3-year old children (n?=?541; 53.9 % male) to compare the internalizing-externalizing latent factor model with a bi-factor model. The bi-factor model provided a better fit to the data. To test the concurrent validity of this solution, we examined associations between this model and paternal reports and laboratory observations of child temperament. The internalizing factor was associated with low levels of surgency and high levels of fear; the externalizing factor was associated with high levels of surgency and disinhibition and low levels of effortful control; and the common factor was associated with high levels of surgency and negative affect and low levels of effortful control. These results suggest that psychopathology in preschool-aged children may be explained by a single, common factor influencing nearly all disorders and unique internalizing and externalizing factors. These findings indicate that shared variance across internalizing and externalizing domains is substantial and are consistent with recent suggestions that emotion regulation difficulties may be a common vulnerability for a wide array of psychopathology.     

Sources of covariation among attention-deficit/hyperactivity disorder, oppositional defiant disorder, and conduct disorder: the importance of shared environment.

Research has documented high levels of covariation among childhood externalizing disorders, but the etiology of this covariation is unclear. To unravel the sources of covariation among attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD), the authors studied 11-year-old twins (N = 1,506) from the Minnesota Twin Family Study. Symptom counts for each of these disorders were obtained from interviews administered to the twins and their mothers. A model was fit that allowed the parsing of genetic, shared environmental (factors that make family members similar to each other), and nonshared environmental (factors that make family members different from each other) contributions to covariation. The results revealed that although each disorder was influenced by genetic and environmental factors, a single shared environmental factor made the largest contribution to the covariation among ADHD, ODD, and CD.     

The Association between Positive Parenting and Externalizing Behavior

The present study examined the role of positive parenting on externalizing behaviors in a longitudinal, genetically informative sample. It often is assumed that positive parenting prevents behavior problems in children via an environmentally mediated process. Alternatively, the association may be due to either an evocative gene-environment correlation, in which parents react to children's genetically-influenced behavior in a positive way, or a passive gene-environment correlation, where parents passively transmit a risk environment and the genetic risk factor for the behavioral outcome to their children. The present study estimated the contribution of these processes in the association between positive parenting and children's externalizing behavior. Positive parenting was assessed via observations at ages 7, 9, 14, 24, and 36 months and externalizing behaviors were assessed through parent report at ages 4, 5, 7, 9, 10, 11, and 12 years. The significant association between positive parenting and externalizing behavior was negative, with children of mothers who showed significantly more positive parenting during toddlerhood having lower levels of externalizing behavior in childhood; however, there was not adequate power to distinguish whether this covariation was due to genetic, shared environmental, or nonshared environmental influences.     

Etiological Contributions to the Covariation Between Children’s Perceptions of Inter-Parental Conflict and Child Behavioral Problems

Prior work has suggested that inter-parental conflict likely plays an etiological role in child behavior problems. However, family-level measurement of inter-parental conflict in most traditional child twin studies has made it difficult to tease apart the specific causal mechanisms underlying this association. The Children’s Perception of Inter-parental Conflict scale (CPIC) provides a child-specific measurement tool for examining these questions, as its subscales tap multiple dimensions of conflict assessed from the child’s (rather than the parent’s) perspective. The current study examined (1) the degree of genetic and environmental influence on each of the CPIC subscales, and (2) etiological contributions to the covariation between the CPIC scales and parental reports of child behavioral problems. The CPIC was completed by 1,200 child twins (aged 6–11 years) from the Michigan State University Twin Registry (MSUTR). Parents completed the Child Behavior Checklist (CBCL) to assess child internalizing and externalizing behavior problems. Multivariate models were examined to evaluate the relative contributions of genetic and environmental factors to both the CPIC scales and to their overlap with child behavioral outcomes. Modeling results indicated no significant moderation of sex or age. Significant environmental overlap emerged between the CPIC conflict properties scale and child internalizing and externalizing problems. By contrast, significant genetic correlations emerged between the CPIC self-blame scale and externalizing problems as well as between the CPIC threat scale and internalizing problems. Overall, findings suggest that the subscales of the CPIC are somewhat etiologically diverse and may provide a useful tool for future investigations of possible gene-environment interplay.     

Seesaw Discipline: The Interactive Effect of Harsh and Lax Discipline on Youth Psychological Adjustment

Although extant research documents the negative consequences of harsh and lax discipline for youth, little empirical attention has been devoted to understanding the impact when parents utilize both strategies. As such, the current study was designed to explore the interaction of harsh and lax discipline on youth internalizing and externalizing symptoms in three developmental periods (early childhood, middle childhood, and adolescence). Participants were 615 parents (55 % female) and one of their 3–17 year old children (45 % female). Parents provided reports of their harsh and lax parenting tactics as well as offspring internalizing and externalizing symptoms. Multiple linear regression analyses were utilized to examine the relations between the interaction of harsh and lax parenting on youth symptoms. The interaction between harsh and lax discipline was significantly related to youth internalizing, but not externalizing, problems in the both the young and middle childhood samples and marginally significant in the adolescence sample: seesaw discipline—a novel construct indicative of high levels of both harsh and lax discipline—was associated with the highest levels of youth internalizing problems. Parents who engage in seesaw parenting have children and adolescents who are more likely to evidence internalizing symptoms. Such findings may inform prevention and intervention efforts that target dysfunctional discipline.     

Family Conflict Moderates the Relation Between Negative Mood and Youth Internalizing and Externalizing Symptoms

Higher negative (or lower positive) mood is associated with internalizing and externalizing problems among some, but not all youth, suggesting that contextual factors may influence these temperament-symptom relations. Family conflict also is associated with internalizing and externalizing problems, although it is unclear whether family conflict influences the relation between negative mood and symptoms. To address this gap, we examined whether family conflict moderates the relations between temperamental negative mood and internalizing and externalizing symptoms. Participants were 775 youth (69?% male, 76?% Caucasian). Mothers and youth completed questionnaires when youth were ages 10–12 (time 1) and 12–14 (time 2). When exposed to higher family conflict at time 1, children higher in negative mood experienced higher time 2 internalizing and externalizing problems than children lower in negative mood. When exposed to lower family conflict, children’s internalizing and externalizing symptom levels were similar regardless of their levels of negative mood. Findings suggest that interventions aimed at reducing youth’s risk for internalizing and externalizing symptoms should address conflictual interactions within the larger family system, particularly among youth with higher negative mood.     

Examining Alternative Explanations of the Covariation of ADHD and Anxiety Symptoms in Children: A Community Study

Attention-deficit hyperactivity disorder (ADHD) is comorbid with a range of other disorders, including anxiety disorders. The aim was to examine different explanations for the covariation of these symptom domains in children according to the framework provided by (Lilienfeld, S. O. Comorbidity between and within childhood externalizing and internalizing disorders: Reflections and directions. Journal of Abnormal Child Psychology, 2003). The covariation of ADHD symptoms and anxiety symptoms were examined over a 12-month period in a community sample of 499 children aged 8-13; 91% were retained at 12-month follow-up. Dimensional assessments were conducted using questionnaires given to children, parents and teachers, with results analyzed via structural equation modeling. Positive associations between ADHD and anxiety symptoms were linked with inattention symptoms, were particularly pronounced for girls, and were linked via temperament and behavioral problems. No support for the hypothesis that ADHD symptoms predicted the development of anxiety symptoms over time or vice versa. ADHD symptoms (particularly inattention) and anxiety symptoms are covarying phenomena that are linked with an irritable temperament and disruptive behavior.     

Differential risks of covarying and pure components in mother and teacher reports of externalizing and internalizing behavior across ages 5 to 14

In a sample of 585 children assessed in kindergarten through 8th grade, we fit a confirmatory factor model to both mother- and teacher-reported symptoms on the Achenbach checklists (CBCL, TRF) and determined that a covariation factor of externalizing and internalizing behaviors existed, in addition to the pure-form factors of externalizing and internalizing for each reporter. In 3 structural equation models, between 8 and 67% of the variance in these 6 latent factors was accounted for by a set of antecedent child, sociocultural, parenting, and peer risk variables. Each of the 6 latent factors, taken 2 at a time, was predicted by a unique set of risk variables; however, there were some patterns that held for both mother- and teacher-report symptom factors: Child temperamental unadaptability and female gender were predictors of higher internalizing symptoms; child temperamental resistance to control, parental harsh punishment, male gender, low SES, and peer rejection were related to higher externalizing symptoms whereas child temperamental unadaptability was related to lower externalizing symptoms; and peer rejection and family stress were also related to the covarying, externalizing-plus-internalizing component of both mother and teacher reports.     

母亲抑郁和惩罚对儿童早期问题行为的影响及父亲的保护作用

儿童早期是母亲消极情绪和行为的易感期,母亲抑郁和消极的教养行为可能导致儿童早期多方面的发展问题,而父亲的积极教养则可能对孩子的健康发展起到保护作用。本研究以184名学前儿童的父亲和母亲为被试,考察母亲抑郁情绪和惩罚行为对儿童问题行为的影响及作用机制,以及父亲积极鼓励在其中的调节作用。结果发现:(1)母亲抑郁显著预测儿童的内向问题行为,母亲惩罚显著预测内向和外向问题行为;(2)母亲抑郁完全通过其惩罚行为影响儿童的外向问题行为,部分通过惩罚影响儿童的内向问题行为;(3)父亲积极鼓励显著调节母亲抑郁对外向问题行为的影响,边缘显著调节母亲抑郁对内向问题行为的影响;父亲积极鼓励对母亲惩罚与内、外向问题行为之间的关系的调节不显著,表明积极的父亲鼓励可以缓冲母亲抑郁对儿童问题行为的影响。     

Comorbidity between and within childhood externalizing and internalizing disorders: reflections and directions

The term and concept of lcomorbidity has been mired in controversy, although there is little question that the existence of covariation among psychiatric diagnoses poses significant challenges to current models of psychiatric classification and diagnosis. The papers in this Special Section underscore a number of important issues relevant to the comorbidity between and within childhood externalizing and internalizing disorders, and illustrate both methodological and substantive reasons for such comorbidity. Weiss, Susser, and Catron's distinction among common, broad-band specific, and narrow-band specific features provides a helpful framework for understanding the comorbidity of childhood externalizing and internalizing disorders (B, Weiss, K. Susser, & T. Catron, 1998). Hierarchical models of psychopathology help to dissolve the distinction between splitters and lumpers and point to variables that may elucidate the etiology of externalizing and internalizing disorders.     

Examining pathways linking maternal depressive symptoms in infancy to children’s behavior problems: The role of maternal unresponsiveness and negative behaviors

The extent to which maternal depressive symptoms in the first 6 months of life is linked with internalizing and externalizing behaviors in childhood through specific insensitive maternal behaviors (unresponsive and overtly negative behaviors) was examined in a sample of 259 mother-infant dyads. In addition, the extent to which these paths were moderated by infant negative emotionality was also examined. Maternal depressive symptoms were assessed prenatally and when infants were 6 months and 2 years old. Maternal unresponsive and overtly negative behaviors and infant negative emotionality were observed when infants were 6 months old. Mothers reported on infant’s internalizing and externalizing behaviors when infants were 2 years old. Maternal depressive symptoms were directly associated with higher internalizing behaviors; this path was not mediated by maternal behaviors. Depressive symptoms were unrelated to externalizing symptoms. Infant negative emotionality did not moderate these effects, but was related positively to overtly negative maternal behaviors, and temperament interacted with maternal depressive symptoms to predict unresponsive maternal behaviors. Results suggest that early maternal depressive symptoms, infant negative emotionality, and negative maternal behavior pose risk for infants’ later internalizing behaviors, but the proposed moderated mediation model was not supported.     

Do Genetic Factors Explain the Links Between Callous-Unemotional,Attention Hyperactivity and Oppositional Defiant Problems in Toddlers?

Research demonstrates that callous-unemotional (CU) behaviors, Attention Deficit Hyperactivity Disorder (ADHD) and Oppositional Defiant Problems (ODD) are related, but little is known about the sources of covariation among the three externalizing behaviors. The present study looked at genetic and environmental links between all three behavioral domains in twins at ages 2 and 3 years (MZ = 145, DZ = 169), a time when CU behaviors are beginning to emerge. CU, ADHD, and ODD behaviors as assessed using the Child Behavior Checklist 1.5–5 (Achenbach and Rescorla 2000) were strongly interrelated at both ages. Genetic factors primarily explained the covariation among the three behavioral domains via a common externalizing factor; however, there were also genetic factors unique to each behavior. Furthermore, the majority of nonshared environmental influences on each externalizing behavior were behavior-specific. The heritable externalizing factor was highly stable across age, largely due to genetic factors shared across ages 2 and 3 years. Despite their extensive phenotypic and genetic overlap, CU, ADHD, and ODD behaviors have unique genetic and nonshared environmental influences as early as toddlerhood. This supports phenotypic research showing that the three are related but distinct constructs in very young children.     

Distress tolerance and early adolescent externalizing and internalizing symptoms: The moderating role of gender and ethnicity

A large body of research has examined the development of internalizing and externalizing symptoms in childhood and early adolescence. Notably, there is significant concomitant impairment associated with early adolescent symptomatology, as well as association of these symptoms with future development of psychopathology, poor physical health, self-destructive thoughts and behaviors, criminal behavior, and HIV risk behaviors. Drawing on negative reinforcement theory, the current study sought to examine the potential role of distress tolerance, defined as the ability to persist in goal-directed activity while experiencing emotional distress, as a potential mechanism that may underlie both internalizing and externalizing symptoms among 231 Caucasian and African American youth (M age = 10.9 years; 45.5% female; 54.5% Caucasian ethnicity). A series of regressions resulted in significant moderated relationships, such that low distress tolerance conferred increased risk for alcohol use among Caucasians, delinquent behavior among African Americans, and internalizing symptoms among females. Clinical implications, including the potential role of negative reinforcement models in early intervention with young adolescents, are discussed.     

Personality-based latent classes of posttraumatic psychopathology: personality disorders and the internalizing/externalizing model

Prior research using the Brief Form of the Multidimensional Personality Questionnaire (MPQ-BF; Patrick, Curtin, & Tellegen, 2002) has shown evidence of 3 temperament-based subtypes--termed internalizing, externalizing, and simple PTSD--among individuals with symptoms of posttraumatic stress disorder (PTSD; Miller, Greif, & Smith, 2003). This study sought to replicate and extend research in this area by conducting a latent profile analysis of higher order temperament scales from the MPQ-BF using a new sample of 208 veterans with symptoms of PTSD. Results suggest that a 3-class solution reflecting internalizing, externalizing, and simple subtypes of posttraumatic psychopathology provided the best fit to the data. The externalizing subtype was characterized by features of antisocial, borderline, histrionic, and narcissistic personality disorders on the International Personality Disorder Examination (Loranger, 1999) as well as low levels of constraint and high levels of negative emotionality on the MPQ-BF. In contrast, individuals in the internalizing class exhibited features of schizoid and avoidant personality disorders, low levels of positive emotionality, and high levels of negative emotionality. The simple subtype was defined by low levels of comorbid personality disorder features and relatively normal personality profiles. Findings support the reliability of this typology and support the relevance of the internalizing and externalizing model to the structure of personality disorders.