Bidirectional influences between maternal parenting and children's peer problems: a longitudinal monozygotic twin difference study

This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin difference scores revealed that authoritative parenting (the presence of consistent discipline and lack of harsh parenting) and peer problems simultaneously influenced each other. Authoritative parenting reduced peer problems, and peer problems increased authoritative parenting. Neither consistent discipline nor harsh parenting alone was associated with peer problems. These results suggest that maternal authoritative parenting works protectively in regard to children's peer problems, and peer problems can evoke such effective parenting.     

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.     

A genetically informed study of associations between family functioning and child psychosocial adjustment

Research has documented associations between family functioning and offspring psychosocial adjustment, but questions remain regarding whether these associations are partly due to confounding genetic factors and other environmental factors. The current study used a genetically informed approach, the Children of Twins design, to explore the associations between family functioning (family conflict, marital quality, and agreement about parenting) and offspring psychopathology. Participants were 867 twin pairs (388 monozygotic; 479 dizygotic) from the Twin and Offspring Study in Sweden, their spouses, and children (51.7% female; M = 15.75 years). The results suggested associations between exposure to family conflict (assessed by the mother, father, and child) and child adjustment were independent of genetic factors and other environmental factors. However, when family conflict was assessed using only children's reports, the results indicated that genetic factors also influenced these associations. In addition, the analyses indicated that exposure to low marital quality and agreement about parenting was associated with children's internalizing and externalizing problems and that genetic factors also contributed to the associations of marital quality and agreement about parenting with offspring externalizing problems.     

Genetic relationships between personality and eating attitudes and behaviors

Genetic and environmental factors underlying relationships between personality traits and disordered eating were examined in 256 female adolescent twin pairs (166 monozygotic, 90 dizygotic). Eating behaviors were assessed with the Total Score, Body Dissatisfaction, Weight Preoccupation, Binge Eating, and Compensatory Behavior subscales from the Minnesota Eating Disorders Inventory (M-EDI; K. L. Klump, M. McGue, & W. G. Iacono, 2000). Personality characteristics were assessed with the Negative Emotionality, Positive Emotionality, and Constraint scales from the Multidimensional Personality Questionnaire (MPQ; A. Tellegen, 1982). Model-fitting analyses indicated that although genetic factors were more likely to contribute to MPQ and M-EDI phenotypic associations than environmental factors, shared genetic variance between the 2 phenotypes was limited. MPQ personality characteristics may represent only some of several genetic risk factors for eating pathology.     

Negative Affect Shares Genetic and Environmental Influences with Symptoms of Childhood Internalizing and Externalizing Disorders

The co-occurrence of internalizing and externalizing disorders suggests that they may have common underlying vulnerability factors. Research has shown that negative affect is moderately positively correlated with both internalizing and externalizing disorders in children. The present study is the first to provide an examination of negative affect in relation to a wide spectrum of childhood internalizing and externalizing problems using a biometric model. This study extends prior findings of more narrowly focused associations by using a factor approach including multiple disorders. The sample for this study included families of 691 same-sex 7- to 13-year old twin pairs. A multifactorial independent pathway model was used to examine the genetic and environmental influences underlying the covariation of parent-reported negative affect, internalizing symptoms, and externalizing symptoms. Results of the current study suggest that negative affect shares genetic and environmental influences with both internalizing and externalizing disorders in childhood. These common influences may partially explain their comorbidity. Understanding that negative affect is at least one contributor to the covariation among these disorders may highlight avenues for early risk assessment, intervention, and perhaps prevention.     

Genetic and Environmental Pathways Underlying Personality Traits and Perceived Stress: Concurrent and Longitudinal Twin Studies

The present study examined the genetic and environmental etiology underlying the Big Five personality traits and perceived stress, concurrently and longitudinally. In study 1, we used the twin sample from the National Longitudinal Study of Adolescent to Adult Health (Add Health IV) data. The results indicated that about 70% of the association between the Big Five personality traits and perceived stress was due to genetic influences. In study 2, we used the twin sample from the Midlife in the United States Survey (MIDUS I and II) to examine the genetic and environmental influences underlying the longitudinal relations between the Big Five personality traits and perceived stress. The results suggested that continuity in perceived stress was primarily accounted for by genetic influences, and changes in perceived stress were mainly due to nonshared environmental influences. The continuity in the association between the five personality traits and perceived stress was largely accounted for by genetic factors, and nonshared environmental factors made greater contributions to changes in the association between personality traits and perceived stress. Among the Big Five personality traits, the genetic components in conscientiousness and neuroticism made substantial contributions to the genetic link between personality traits and perceived stress across both studies. Copyright © 2017 European Association of Personality Psychology     

Genetic and environmental contributions to the co-occurrence of depressive personality disorder and DSM-IV personality disorders

One of the main controversies with regard to depressive personality disorder (DPD) concerns the co-occurrence with the established DSM-IV personality disorders (PDs). The main aim of this study was to examine to what extent DPD and the DSM-IV PDs share genetic and environmental risk factors, using multivariate twin modeling. The DSM-IV Structured Interview for Personality was applied to 2,794 young adult twins. Paranoid PD from Cluster A, borderline PD from Cluster B, and all three PDs from Cluster C were independently and significantly associated with DPD in multiple regression analysis. The genetic correlations between DPD and the other PDs were strong (.53-.83), while the environmental correlations were moderate (.36-.40). Close to 50% of the total variance in DPD was disorder specific. However, only 5% was due to disorder-specific genetic factors, indicating that a substantial part of the genetic vulnerability to DPD also increases the vulnerability to other PDs.     

Normal and abnormal personality traits: evidence for genetic and environmental relationships in the Minnesota Study of Twins Reared Apart

ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI)—an index of abnormal personality—and the Multidimensional Personality Questionnaire (MPQ)—an index of normal personality—were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality.     

A behavior-genetic study of parenting quality, infant attachment security, and their covariation in a nationally representative sample

A number of relatively small-sample, genetically sensitive studies of infant attachment security have been published in the past several years that challenge the view that all psychological phenotypes are heritable and that environmental influences on child development--to the extent that they can be detected--serve to make siblings dissimilar. Using the twin subsample (N = 485 same-sex pairs) of the nationally representative Early Childhood Longitudinal Study-Birth Cohort, the authors provide evidence that parenting quality and infant attachment security observed at 24 months, as well as their covariation, are a product of shared and nonshared environmental (but not genetic) variation among children. In contrast, genetic differences between infants played a prominent role in explaining observations of temperamental dependency.     

Difficult temperament and negative parenting in early childhood: a genetically informed cross‐lagged analysis

A genetically informed longitudinal cross‐lagged model was applied to twin data to explore etiological links between difficult temperament and negative parenting in early childhood. The sample comprised 313 monozygotic (MZ) and dizygotic (DZ) twin pairs. Difficult temperament and negative parenting were assessed at ages 2 and 3 using parent ratings. Both constructs were interrelated within and across age (rs .34–.47) and showed substantial stability (rs .65–.68). Difficult temperament and negative parenting were influenced by genetic and environmental factors at ages 2 and 3. The genetic and nonshared environmental correlations (rs .21–.76) at both ages suggest overlap at the level of etiology between the phenotypes. Significant bidirectional associations between difficult temperament and negative parenting were found. The cross‐lagged association from difficult temperament at age 2 to negative parenting at age 3 and from negative parenting at age 2 and difficult temperament at age 3 were due to genetic, shared environmental, and nonshared environmental factors. Substantial novel genetic and nonshared environmental influences emerged at age 3 and suggest change in the etiology of these constructs over time.     

Understanding child-based effects on parenting: temperament as a moderator of genetic and environmental contributions to parenting

The degree to which child temperament moderates genetic and environmental contributions to parenting was examined. Participants were drawn from the Nonshared Environment and Adolescent Development project and included 720 sibling pairs, ages 13.5 + 2.0 years (Sibling 1) to 12.1 + 1.3 years (Sibling 2). The sample consisted of 6 sibling types: 93 monozygotic twin pairs, 99 dizygotic twin pairs, and 95 full sibling pairs from never-divorced families and 182 full-sibling, 109 half-sibling, and 130 unrelated-sibling pairs residing in stepfamilies. Composite child temperament ratings (negative emotionality, activity, shyness, and sociability) were derived from mothers' and fathers' reports. Composite parenting ratings (negativity, warmth) for mothers and fathers were generated from children's and parents' reports. Analyses indicated that at higher levels of negative emotionality and sociability, child-based genetic contributions to mothers' and fathers' negativity increased, whereas the contributions of environmental factors declined. The opposite pattern was observed for child shyness. These same characteristics had less impact on parental warmth. For fathers only, nonshared environmental contributions to fathers' warmth increased in the presence of high child activity and sociability but declined when children were very shy. Overall these findings indicate that child-based effects on negative parenting are enhanced when children demonstrate potentially challenging characteristics but are weaker in the absence of such characteristics.     

A Genetically Informed Study of the Covariation Between Childhood Anxiety Dimensions and Social Competence

We investigated the nature of latent shared etiological elements in 398 Italian twin pairs aged 8–17, explaining covariation between high levels of anxiety symptoms and low social competence. We found significant negative correlations between Child Behaviour Checklist/6–18 Social Competence Scale and three (Panic Anxiety, Separation Anxiety, Social Anxiety) out of five Screen for Child Anxiety Related Disorders anxiety subscales. Results from causal analysis seem to exclude the hypothesis that co-occurrence between Anxiety Symptoms and Social Competence could be due to a direct phenotypic effect of one trait upon the other. Multivariate analysis suggested that both genetic and shared environmental components contribute to the phenotypic correlation between Social Competence and Anxiety Subscales, whereas unique environmental factors have a negligible influence. This means that both common genetic and shared environmental causal factors contribute simultaneously to increase risk of having low Social Competence and high Anxiety scores. In particular, covariation with Social Competence seems to be influenced by both genetic and shared environmental causal components in Separation Anxiety and Social Anxiety, whereas environmental factors have an irrelevant influence for covariation with Panic/Somatic Anxiety Subscale. Our results support the adoption of a broader view of the relationships between psychopathology and diminished social competences in childhood for both clinicians and educators.     

Self‐rated personality and intelligence: a multivariate genetic analysis

The present study investigated the phenotypic, genetic, and environmental correlations between personality factors and measured intelligence. Twin pairs (92 monozygotic and 50 same sex dizygotic) completed 20 sets of personality adjectives in self‐report form as well as a group administered intelligence test, measuring general intelligence and verbal and performance composite scales. The personality adjectives were found to fit a five factor model. Personality aggregates were also created based on multiple regression analyses and used to predict each intelligence dimension. Triangular decompositions were computed to estimate the degree to which the phenotypic personality and intelligence relations were attributable to common genetic and/or environmental factors. Results of these analyses found small to moderate genetic and environmental correlations between intelligence and the personality factors, and moderate to high genetic correlations between intelligence and the personality aggregates, suggesting that intelligence is related to some personality traits at both the phenotypic and the genetic level. Copyright © 1999 John Wiley & Sons, Ltd.     

General and supplementary factors of personality in genetic and environmental correlation matrices

Genetic and environmental correlation matrices among 7 personality scales were estimated, using samples of adult and young adult twins from Australia (2081 and 1178 pairs, respectively). A general factor of personality and two supplemental factors were obtained in each. The supplemental factors were tentatively identified as Social conformity and Other-dependence. Factors from the genetic and environmental correlations replicated well across samples, and they were similar in both the genetic and environmental covariation. It was concluded that the structure of personality is inherent in the evolved phenotype, and is not the immediate consequence of either genetic or environmental organizing factors.     

Modeling Rater Disagreement for ADHD: Are Parents or Teachers Biased?

The present study is the first to utilize twin modeling to examine whether parent-teacher disagreement for ADHD ratings is due to parent or teacher bias, or due to raters observing different but valid ADHD behaviors. A joint analysis was conducted with 106 twin pairs, including twins selected for ADHD and control twin pairs. Total ADHD scores were analyzed using multiple rater models that estimate genetic and environmental contributions common to both raters and unique to each rater. Results suggest that 1) disagreement in ADHD ratings is strongly due to parents and teachers observing different ADHD behaviors, some of which is valid and some of which is due to bias, and 2) parents may be more biased than teachers in their ADHD ratings.     

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.     

Early childhood cognitive development and parental cognitive stimulation: evidence for reciprocal gene-environment transactions

Parenting is traditionally conceptualized as an exogenous environment that affects child development. However, children can also influence the quality of parenting that they receive. Using longitudinal data from 650 identical and fraternal twin pairs, we found that, controlling for cognitive ability at age 2 years, cognitive stimulation by parents (coded from video recorded behaviors during a dyadic task) at 2 years predicted subsequent reading ability at age 4 years. Moreover, controlling for cognitive stimulation at 2 years, children's cognitive ability at 2 years predicted the quality of stimulation received from their parents at 4 years. Genetic and environmental factors differentially contributed to these effects. Parenting influenced subsequent cognitive development through a family-level environmental pathway, whereas children's cognitive ability influenced subsequent parenting through a genetic pathway. These results suggest that genetic influences on cognitive development occur through a transactional process, in which genetic predispositions lead children to evoke cognitively stimulating experiences from their environments.     

Genetic effects explain the stability of psychopathic personality from mid- to late adolescence

This study examined the importance of genetic and environmental influence for the stability of psychopathic personality between mid- and late adolescence. The target sample consisted of all 1,480 male and female twin pairs born in Sweden between 1985 and 1986. Psychopathic personality was measured with the Youth Psychopathic Traits Inventory (YPI; H. Andershed, M. Kerr, M. Stattin, & S. Levander, 2002) when the participants were 16 and 19 years old. Results showed that the 3 psychopathic personality dimensions were stable at different levels of analysis and linked to a stable higher order general factor (i.e., psychopathic personality factor). Genetic factors contributed substantially to the stability of this general higher order factor, whereas environmental factors were of little importance. However, the authors also found specific genetic stability in the Callous/unemotional and Impulsive/irresponsible dimension. Thus, the model provides evidence for etiologic generality and etiologic specificity for the stability of psychopathic personality between mid- and late adolescence.     

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.     

Nonshared environmental processes in social‐emotional development: an observational study of identical twin differences in the preschool period

Differences in mothers’ parenting behaviors toward their identical twin preschoolers were examined to identify nonshared environmental processes in social‐emotional development. The study included 62 pairs of 3½‐year‐old same‐sex identical twins. Indicators of each child’s social‐emotional development (temperament, prosocial behavior, behavior problems and noncompliance) and parenting environment (warmth and negativity, positive and negative control, responsiveness) were assessed using observers’, interviewers’, and parents’ ratings. Mothers treated their identical twins differently, and this differential treatment covaried in expected ways with identical twin differences in social‐emotional adjustment. The twin who received more supportive and less punitive forms of parenting was also higher in positive mood and prosocial behaviors and lower in negative mood and behavior problems when compared to her or his twin.