Whereas socialization influences in early childhood have been linked to children's emerging internalizing problems and prosocial behavior, relatively few studies have examined how NE might moderate such associations in both advantageous and maladaptive ways. Furthermore, more research is needed to evaluate the impact of sibling relationships as an…

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…

Prior studies have indicated that the relationship between parent-child conflict and adolescent antisocial behavior is at least partially shared environmental in origin. However, all available research on this topic (to our knowledge) relies exclusively on parent and/or adolescent informant-reports, both of which are subject to various forms of…

Endophenotypes or intermediate phenotypes are of great interest in neuropsychiatric genetics because of their potential for facilitating gene discovery. We evaluated response inhibition, latency and variability measures derived from the stop task as endophenotypes of ADHD by testing whether they were related to ADHD traits in the general…

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…

It has recently been argued that shared environmental influences are moderate, identifiable, and persistent sources of individual differences in most forms of child and adolescent psychopathology, including antisocial behavior. Unfortunately, prior studies examining the stability of shared environmental influences over time were limited by…

Behaviors characteristic of autism and ADHD emerge in early childhood, yet research investigating their comorbidity has focused on older children. This study aimed to explore the nature of the relationship between autistic-like traits and ADHD behaviors in a community sample of 2-year-olds. Twins from the Boston University Twin Project (N = 312…

The study presents a quasi-experimental analysis of data on 9,194 offspring (ages 4-11 years old) of women from a nationally representative U.S. sample of households to test the causal hypotheses about the association between family income and childhood conduct problems (CPs). Comparison of unrelated individuals in the sample indicated a robust…

Using an accelerated longitudinal design, the development of externalizing problems from age 2 to 5 years was investigated in relation to maternal psychopathology, maternal parenting, gender, child temperament, and the presence of siblings. The sample consisted of 150 children selected at age 2-3 years for having high levels of externalizing…

We aimed to assess which comorbid problems (oppositional defiant behaviors, anxiety, autistic traits, motor coordination problems, and reading problems) were most associated with Attention-Deficit/Hyperactivity Disorder (ADHD); to determine whether these comorbid problems shared executive and motor problems on an endophenotype level with ADHD; and…

Structural equation modeling (SEM) was used to examine the development of intellectual functioning in 145 school-age pairs of siblings. Each pair included one child with Fragile X syndrome (FXS) and one unaffected sibling. All pairs of children were evaluated on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) at time 1 and 80…

This study investigated the quality of sibling relationships and sibling deviancy in a sample of children at-risk for substance use and antisocial behavior. Based on a history of empirical and theoretical models suggesting strong associations between children's development in the context of relationships and the emergence of delinquency and drug…

The aims of this study were to investigate whether subtle PDD symptoms in the context of ADHD are transmitted in families independent of ADHD, and whether PDD symptom familiality is influenced by gender and age. The sample consisted of 256 sibling pairs with at least one child with ADHD and 147 healthy controls, aged 5-19 years. Children who…

Few studies have examined the impact of children with genetic disorders and their unaffected siblings on family functioning. In this study, the reciprocal causal links between problem behaviors and maternal distress were investigated in 150 families containing a child with fragile X syndrome (FXS) and an unaffected sibling. Both children's…

Few genetically-informative studies have attempted to explicitly identify the "shared environmental" (i.e., those environmental influences that contribute to sibling similarity) factors now known to contribute to adolescent delinquency. The current study therefore examined whether the parent-child relationship served as one source of these shared…