Genetic analyses of the stability of executive functioning during childhood

How does sensitivity influence early executive function? A critical review on hot and cool processes

There is compelling evidence that the quality of caregiver-child interactions during toddlerhood and the preschool years supports the development of executive function (EF) (Bernier et al., 2010; 2015; 2016; Fay-Stammbach et al., 2014; Geeraerts et al., 2021). Based on such findings, we make the case herein that sensitivity may be one of the most important dimensions of parenting contributing to early EF. In the present article, we will review empirical evidence, integrating findings from a wide range of scientific disciplines - cognitive psychology, neuroscience, and developmental psychopathology - and present theoretical ideas about how two contexts of sensitive caregiving - i.e. sensitivity to distress and non-distress cues - may be contributing differently to hot and cool EF development. Implications for future investigations on the environmental contributors of early EF, and its mechanisms, are discussed.

Executive function as a generalized determinant of psychopathology and functional outcome in school-aged autism spectrum disorder: a case-control study

BACKGROUND

Individuals with autism spectrum disorder (ASD) are challenged not only by the defining features of social-communication deficits and restricted repetitive behaviors, but also by a myriad of psychopathology varying in severity. Different cognitive deficits underpin these psychopathologies, which could be subjected to intervention to alter the course of the disorder. Understanding domain-specific mediating effects of cognition is essential for developing targeted intervention strategies. However, the high degree of inter-correlation among different cognitive functions hinders elucidation of individual effects.

METHODS

In the Philadelphia Neurodevelopmental Cohort, 218 individuals with ASD were matched with 872 non-ASD controls on sex, age, race, and socioeconomic status. Participants of this cohort were deeply and broadly phenotyped on neurocognitive abilities and dimensional psychopathology. Using structural equation modeling, inter-correlation among cognitive domains were adjusted before mediation analysis on outcomes of multi-domain psychopathology and functional level.

RESULTS

While social cognition, complex cognition, and memory each had a unique pattern of mediating effect on psychopathology domains in ASD, none had significant effects on the functional level. In contrast, executive function was the only cognitive domain that exerted a generalized negative impact on every psychopathology domain (p factor, anxious-misery, psychosis, fear, and externalizing), as well as functional level.

CONCLUSIONS

Executive function has a unique association with the severity of comorbid psychopathology in ASD, and could be a target of interventions. As executive dysfunction occurs variably in ASD, our result also supports the clinical utility of assessing executive function for prognostic purposes.

Early manifestations of intellectual performance: Evidence that genetic effects on later academic test performance are mediated through verbal performance in early childhood

Intellectual performance is highly heritable and robustly predicts lifelong health and success but the earliest manifestations of genetic effects on this asset are not well understood. This study examined whether early executive function (EF) or verbal performance mediate genetic influences on subsequent intellectual performance, in 561 U.S.-based adoptees (57% male) and their birth and adoptive parents (70% and 92% White, 13% and 4% African American, 7% and 2% Latinx, respectively), administered measures in 2003-2017. Genetic influences on children's academic performance at 7 years were mediated by verbal performance at 4.5 years (β = .22, 95% CI [0.08, 0.35], p = .002) and not via EF, indicating that verbal performance is an early manifestation of genetic propensity for intellectual performance.

Lifetime stressors, hair cortisol, and executive function: Age-related associations in childhood

Extant research is mixed regarding the relations among lifetime exposure to stressors, adrenocortical activity, and executive function (EF), particularly in children. Aggregate measures of adrenocortical activity like hair cortisol concentration (HCC), timing of stress exposure, and age at assessment may clarify these associations. This cross-sectional study examined the association among parent-reported exposure to stressors, hair cortisol concentration (HCC), and children's EF via a tablet task in a community sample (n = 318, 52.5% female) of children across a wide age range (4-13 years, M = 9.4, SD = 2.3). Path analyses revealed that parent-reported child lifetime exposure to stressors, but not past-year stressful life events, negatively predicted HCC. There was also a marginally significant moderation by age such that HCC was associated negatively with EF for younger children (age < 9.7 years) but not older children. HCC did not significantly mediate the association between lifetime exposure to stressors and EF. Findings are consistent with the proposition that chronically high cortisol production has a neurotoxic effect on brain regions supporting EF. However, lifetime exposure to stressors predicted relatively lower cumulative cortisol production, consistent with a stress inoculation effect in this normative-risk sample.

Effects of genetic variability of CYP2D6 on neural substrates of sustained attention during on-task activity

The polymorphic drug-metabolizing enzyme CYP2D6, which is responsible for the metabolism of most psychoactive compounds, is expressed not only in the liver, but also in the brain. The effects of its marked genetic polymorphism on the individual capacity to metabolize drugs are well known, but its role in metabolism of neural substrates affecting behavior personality or cognition, suggested by its CNS expression, is a long-standing unresolved issue. To verify earlier findings suggesting a potential effect on attentional processes, we collected functional imaging data, while N = 415 participants performed a simple task in which the reward for correct responses varied. CYP2D6 allelic variants predicting higher levels of enzymatic activity level were positively associated with cortical activity in occipito-parietal areas as well as in a right lateralized network known to be activated by spatial attentional tasks. Reward-related modulation of activity in cortical areas was more pronounced in poor metabolizers. In conjunction with effects on reaction times, our findings provide evidence for reduced cognitive efficiency in rapid metabolizers compared to poor metabolizers in on-task attentional processes manifested through differential recruitment of a specific neural substrate.

Measurement of executive functioning with the National Institute of Health Toolbox and the association to anxiety/depressive symptomatology in childhood/adolescence

INTRODUCTION

Despite preliminary research, there remain inconsistent findings with regard to the role of executive functioning (EF) deficits in childhood anxiety and depression. This report examined the association of The National Institute of Health (NIH) Toolbox to clinical neuropsychological measures and to childhood, anxiety/depressive symptomatology. Methods: One-hundred eight children and adolescents completed the three EF measures from the NIH Toolbox (List Sorting Working Memory Test [LSWMT], Dimensional Change Card Sorting Test [DCCST], and Flanker Test of Attention and Inhibition [Flanker]) in an outpatient neuropsychology program. These tests were compared to established measures of EF in terms of linear correlations and detection of impairment. Heaton's Global Deficit Score (GDS) was utilized to calculate impairment. The Toolbox-EF measures were paired with parent-reported EF symptoms (Behavior Rating Inventory of Executive Function [BRIEF2]) to identify the role of EF in childhood anxiety/depressive symptomatology.

RESULTS

Toolbox-EF measures displayed medium sized correlations with their clinically comparable counterparts, and generally did not differ in their detection of impairment. Toolbox-GDS was associated with depression diagnosis and clinically significant child-reported anxiety and depressive symptoms. Together, Toolbox/BRIEF2 accounted for 26.8-30.9% of elevated depressive symptom variance, but only 13.2-14% of elevated anxiety symptom variance. Further, EF impairment was associated with depression across self report, parent report, and clinical diagnosis.

DISCUSSION

The NIH Toolbox-EF measures display comparable psychometric properties to clinically available EF measures in a pediatric (primarily psychiatric) neuropsychology setting. The Toolbox appears to display an appropriate ability to detect EF deficits secondary to self-reported depression in childhood.

Internalizing Problems and Attentional Control

Abstract. Individuals with internalizing problems differ in levels of attentional control (AC), and this heterogeneity could be associated with differences in autonomic arousal. The present study investigated whether AC moderated the effect of internalizing problems on self-reported experience and autonomic nervous system (ANS) responses after the induction of negative affect. Children aged 9–13 years were recruited into a patient group (29) and a healthy control group (25). AC was measured by the Early Adolescent Temperament Questionnaire. Heart rate, heart rate variability (HRV) and pre-ejection period (PEP) were recorded during baseline, a sad film clip and recovery, and analyzed using a marginal linear model. Children reported their experienced emotion, valence, and arousal in response to the film. A significant interaction effect showed increased HRV and longer PEP from baseline to recovery for patients with higher AC. Patients with lower AC showed increased HRV followed by a return to baseline values after the film clip and no significant changes in PEP. Healthy controls showed no significant changes in HRV or PEP independent of level of AC. There were no differences between groups in self-reported experience. The results indicate that AC moderated the effect of internalizing problems on ANS regulation. Increased HRV and longer PEP from baseline to recovery were uniquely associated with higher AC and internalizing problems. This physiological response might indicate a cognitive avoidance strategy. AC could be an important factor explaining heterogeneity in ANS activity among individuals with internalizing problems. Clinical implications of the present findings are discussed.

Single nucleotide polymorphism heritability and differential patterns of genetic overlap between inattention and four neurocognitive factors in youth

Theoretical models of attention-deficit/hyperactivity disorder implicate neurocognitive dysfunction, yet neurocognitive functioning covers a range of abilities that may not all be linked with inattention. This study (a) investigated the single nucleotide polymorphism (SNP) heritability (h2SNP) of inattention and aspects of neurocognitive efficiency (memory, social cognition, executive function, and complex cognition) based on additive genome-wide effects; (b) examined if there were shared genetic effects among inattention and each aspect of neurocognitive efficiency; and (c) conducted an exploratory genome-wide association study to identify genetic regions associated with inattention. The sample included 3,563 participants of the Philadelphia Neurodevelopmental Cohort, a general population sample aged 8-21 years who completed the Penn Neurocognitive Battery. Data on inattention was obtained with the Kiddie Schedule of Affective Disorders (adapted). Genomic relatedness matrix restricted maximum likelihood was implemented in genome-wide complex trait analysis. Analyses revealed significant h2SNP for inattention (20%, SE = 0.08), social cognition (13%, SE = 0.08), memory (17%, SE = 0.08), executive function (25%, SE = 0.08), and complex cognition (24%, SE = 0.08). There was a positive genetic correlation (0.67, SE = 0.37) and a negative residual covariance (-0.23, SE = 0.06) between inattention and social cognition. No SNPs reached genome-wide significance for inattention. Results suggest specificity in genetic overlap among inattention and different aspects of neurocognitive efficiency.

Attention and executive functioning in infancy: Links to childhood executive function and reading achievement

This study provides the first analyses connecting individual differences in infant attention to reading achievement through the development of executive functioning (EF) in infancy and early childhood. Five-month-old infants observed a video, and peak look duration and shift rate were video coded and assessed. At 10 months, as well as 3, 4, and 6 years, children completed age-appropriate EF tasks (A-not-B task, hand game, forward digit span, backwards digit span, and number Stroop). Children also completed a standardized reading assessment and a measure of verbal intelligence (IQ) at age 6. Path analyses on 157 participants showed that infant attention had a direct statistical predictive effect on EF at 10 months, with EF showing a continuous pattern of development from 10 months to 6 years. EF and verbal IQ at 6 years had a direct effect on reading achievement. Furthermore, EF at all time points mediated the relation between 5-month attention and reading achievement. These findings may inform reading interventions by suggesting earlier intervention time points and specific cognitive processes (i.e. 5-month attention).

Genetic overlap between executive functions and BMI in childhood

BACKGROUND

Executive functions (EFs) comprise a group of cognitive processes that selectively control and regulate attention. Inverse relations have been reported between EFs and BMI. However, the mechanisms underlying this association are not well understood.

OBJECTIVES

We aimed to decompose the inverse relation between EFs and BMI into genetic and environmental components.

METHODS

We employed a cross-sectional analysis of data from 869 twins aged 7-15 y from the Texas Twin Project, who completed a neuropsychological test battery measuring 4 EFs (switching, inhibitory control, working memory, and updating); academic achievement (reading and mathematics); and general cognitive abilities (general intelligence/intelligence quotient; crystallized and fluid intelligence; and processing speed). Participants also had their height and weight measured.

RESULTS

After controlling for age, sex, and race/ethnicity, BMI was inversely associated with a general EF factor representing the capacity to control and regulate goal-oriented behaviors (r = -0.125; P = 0.01; Q = 0.04). This inverse BMI-EF association was due to a significant overlap in genetic factors contributing to each phenotype (genetic correlation, rA, = -0.15; P < 0.001). Shared genetic influences accounted for 80% of the phenotypic association.

CONCLUSIONS

Children with higher general EF have lower BMIs, and this association is primarily attributable to shared genetic influences on both phenotypes. The results emphasize that higher weight associates not only with physical sequelae, but also with important cognitive attributes. This work adds to a growing body of research suggesting there are sets of genetic variants common across physical health and cognitive functioning.

Pediatric Eating Behaviors as the Intersection of Biology and Parenting: Lessons from the Birds and the Bees

PURPOSE OF REVIEW

Current feeding advice to prevent pediatric obesity focuses on caregiver feeding behaviors. This review integrates newer data showing that child appetitive traits also have a genetic component.

RECENT FINDINGS

Caregiver feeding behaviors robustly correlate with child eating behaviors; however, there is also a strong heritable component. The satiety cascade delineates the biological drive underlying hunger, satiation, and satiety. Innate individual differences exist for the components of the satiety cascade, which may explain the heritability of child eating behaviors. However, given the correlation of caregiver feeding behaviors with child eating behaviors, any etiological model should include both genetic/biological components and environmental. Integrating the biological etiology of child eating behaviors into the current environmental model has implications for tailoring feeding advice which needs to move from a "one size fits all" approach to one that is tailored to individual differences in children's biological drives to appetite.

CanDiD: A Framework for Linking Executive Function and Education

The close association between executive functions (EFs) and educational achievement has led to the idea that targeted EF training might facilitate learning and goal-directed behavior in the classroom. The evidence that training interventions have long-lasting and transferable effects is however decidedly mixed (Melby-Lervåg and Hulme, 2013; Simons et al., 2016). The goal of the current paper is to propose a new CanDiD framework for re-thinking EF and its links to education. Based on findings from basic EF research, the proposed CanDiD framework highlights dynamic and contextual influences on EF and emphasizes the importance of development and individual differences for understanding these effects. Implications for remedial interventions and curriculum design are discussed.

FATHER-CHILD INTERACTIONS AT 3 MONTHS AND 24 MONTHS: CONTRIBUTIONS TO CHILDREN'S COGNITIVE DEVELOPMENT AT 24 MONTHS

The quality of father–child interactions has become a focus of increasing research in the field of child development. We examined the potential contribution of father–child interactions at both 3 months and 24 months to children's cognitive development at 24 months. Observational measures of father–child interactions at 3 and 24 months were used to assess the quality of fathers’ parenting (n = 192). At 24 months, the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development, Second Edition (N. Bayley, 1993) measured cognitive functioning. The association between interactions and cognitive development was examined using multiple linear regression analyses, adjusting for paternal age, education and depression, infant age, and maternal sensitivity. Children whose fathers displayed more withdrawn and depressive behaviors in father–infant interactions at 3 months scored lower on the MDI at 24 months. At 24 months, children whose fathers were more engaged and sensitive as well as those whose fathers were less controlling in their interactions scored higher on the MDI. These findings were independent of the effects of maternal sensitivity. Results indicate that father–child interactions, even from a very young age (i.e., 3 months) may influence children's cognitive development. They highlight the potential significance of interventions to promote positive parenting by fathers and policies that encourage fathers to spend more time with their young children.

Cognitive functioning in children with internalising, externalising and dysregulation problems: a population-based study

Psychiatric symptoms in childhood are closely related to neurocognitive deficits. However, it is unclear whether internalising and externalising symptoms are associated with general or distinct cognitive problems. We examined the relation between different types of psychiatric symptoms and neurocognitive functioning in a population-based sample of 1177 school-aged children. Internalising and externalising behaviour was studied both continuously and categorically. For continuous, variable-centred analyses, broadband scores of internalising and externalising symptoms were used. However, these measures are strongly correlated, which may prevent identification of distinct cognitive patterns. To distinguish groups of children with relatively homogeneous symptom patterns, a latent profile analysis of symptoms at age 6 yielded four exclusive groups of children: a class of children with predominantly internalising symptoms, a class with externalising symptoms, a class with co-occurring internalising and externalising symptoms, that resembles the CBCL dysregulation profile and a class with no problems. Five domains of neurocognitive ability were tested: attention/executive functioning, language, memory and learning, sensorimotor functioning, and visuospatial processing. Consistently, these two different modelling approaches demonstrated that children with internalising and externalising symptoms show distinct cognitive profiles. Children with more externalising symptoms performed lower in the attention/executive functioning domain, while children with more internalising symptoms showed impairment in verbal fluency and memory. In the most severely affected class of children with internalising and externalising symptoms, we found specific impairment in the sensorimotor domain. This study illustrates the specific interrelation of internalising and externalising symptoms and cognition in young children.

Executive Function Mediates the Relations between Parental Behaviors and Children's Early Academic Ability

The past decade has witnessed a growth of interest in parental influences on individual differences in children's executive function (EF) on the one hand and in the academic consequences of variation in children's EF on the other hand. The primary aim of this longitudinal study was to examine whether children's EF mediated the relation between three distinct aspects of parental behavior (i.e., parental scaffolding, negative parent-child interactions, and the provision of informal learning opportunities) and children's academic ability (as measured by standard tests of literacy and numeracy skills). Data were collected from 117 parent-child dyads (60 boys) at two time points ~1 year apart (M Age at Time 1 = 3.94 years, SD = 0.53; M Age at Time 2 = 5.11 years, SD = 0.54). At both time points children completed a battery of tasks designed to measure general cognitive ability (e.g., non-verbal reasoning) and EF (e.g., inhibition, cognitive flexibility, working memory). Our models revealed that children's EF (but not general cognitive ability) mediated the relations between parental scaffolding and negative parent-child interactions and children's early academic ability. In contrast, parental provision of opportunities for learning in the home environment was directly related to children's academic abilities. These results suggest that parental scaffolding and negative parent-child interactions influence children's academic ability by shaping children's emerging EF.

Longitudinal Associations Between the Quality of Mother-Infant Interactions and Brain Development Across Infancy

The aim of this study was to investigate if normative variations in parenting relate to brain development among typically developing children. A sample of 352 mother-infant dyads came to the laboratory when infants were 5, 10, and 24 months of age (final N = 215). At each visit, child resting electroencephalography (EEG) was recorded. Mother-infant interactions were videotaped at the 5-month visit. The results indicated that higher quality maternal behavior during mother-infant interactions predicted higher frontal resting EEG power at 10 and 24 months, as well as increases in power between 5 and 10 months, and between 10 and 24 months. These findings provide rare support for the hypothesis that normative variation in parenting quality may contribute to brain development among typically developing infants.

Neurocognitive Development After Pediatric Heart Surgery

OBJECTIVES

Children with congenital heart disease (CHD) often have neurocognitive deficits, sometimes with a detrimental impact on daily and school functioning. These deficits may increase through childhood. In this study, we investigated whether children with CHD, who underwent heart surgery as infants, show more neurocognitive deficits, especially in the executive functions, as they get older, compared with healthy controls.

METHODS

In this longitudinal follow-up study, 107 children with CHD and 77 healthy control children underwent extensive neurocognitive testing at 4 years of age. Ninety-three percent of the children (100 patients with CHDs and 72 controls) underwent a second neurocognitive testing 3 years later. Intelligence, visual-motor integration (VMI), alertness, motor coordination, executive functions, and psychosocial functioning were assessed.

RESULTS

IQ scores were consistently lower in the CHD group (P < .001); however, the difference of 11.7 IQ points between both groups at follow-up 1 decreased to 7 IQ points at follow-up 2 (P = .003). Inhibition reaction time had improved in both study groups at follow-up 2 (P < .001) and did not differ between both groups from follow-up 1 to follow-up 2 (P = .849). Deficits in VMI, alertness, motor coordination, and psychosocial functioning also did not worsen for patients with CHDs at follow-up 2, compared with healthy controls.

CONCLUSIONS

Children with CHD, who underwent heart surgery as infants, do not show an increase of neurocognitive deficits between the ages of 4 and 7 years, compared with healthy controls. Patients with CHDs keep deficits in intelligence, VMI, and psychosocial functioning, but seem to partially grow out of their deficits.

Stability and change in executive function abilities from late adolescence to early adulthood: A longitudinal twin study

Executive functions (EFs)-the higher level cognitive abilities that enable us to control our own thoughts and actions-continue to develop into early adulthood, yet no longitudinal study has examined their stability during the important life transition from late adolescence to young adulthood. In this twin study (total N = 840 individuals from 424 families), we examined the stability of individual differences in 3 EF components across a 6-year period, from approximately age 17 years (Wave 1) to 23 years (Wave 2). Specifically, we address the following questions: (a) How stable are individual differences in multiple EFs across this time period? and (b) What (genetic and/or environmental) influences affect stability and change in EFs? Results indicated that individual differences in EFs are quite stable across this 6-year period (phenotypic latent variable correlations ranged from 0.86 to 1.0). However, there was evidence for change, particularly in the factor common to multiple EFs (Common EF). Multivariate twin models suggested that stability was due almost entirely to high genetic correlations across time; there was no new genetic variance at Wave 2. Change in Common EF was due to small but significant nonshared environmental influences at Wave 2 (15%). The results suggest that individual differences in EFs are quite heritable and stable by late adolescence, yet are still sensitive to environmental influences.

Executive functions in early childhood: the role of maternal and paternal parenting practices

We investigated the association between mothers' and fathers' harsh parenting and sensitive parenting practices and child's executive functions (EF) in early childhood in 607 families. We focused on three broad dimensions of child EF: Emergent metacognition, inhibitory self-control, and flexibility measured with the parent-reported Behavior Rating Inventory of Executive Function-Preschool Version. Less sensitive parenting of the mother and harsher parenting of the father were related to lower scores of emergent metacognition and inhibitory self-control. Parenting was not associated with child flexibility. This study extends previous research on the association between parenting and EF by the focus on the role of the father and demonstrates independent effects of mother and father on child EF.

The role of age in association analyses of ADHD and related neurocognitive functioning: A proof of concept for dopaminergic and serotonergic genes

Elucidating genetic mechanisms involved in Attention-Deficit/Hyperactivity Disorder (ADHD) has been challenging. Relatively unexplored is the fact that genetic mechanisms can differ with age. The current study explored the association between dopaminergic and serotonergic genes, ADHD symptoms, and neurocognitive functioning in relation to age. Associations of three genetic ADHD risk factors, DAT1, DRD4, and 5-HTT with symptoms and six neurocognitive measures were explored in two samples of the NeuroIMAGE study: 756 children, adolescents, and young adults with ADHD, their siblings, and controls (M age 17 years, SD 3.2), and 393 parents with and without ADHD (M age 48 years, SD 4.8). Association analyses were performed in both samples, and effects were compared to address dichotomous age effects. Gene*age interactions were examined to address continuous age effects. Moderating effects of age were found for DRD4-7R carriership and ADHD symptoms in the adult group only; in the adolescents the 5-HTT LL genotype was differentially associated with inhibition and with motor timing at different ages, and to inhibition in adults; DAT1 10-6 haplotype carriership showed differential working memory performance depending on age. None of our effects survived correction for multiple comparisons. Our results are preliminary, but may point to differential genotype-phenotype associations at different ages. This can be seen as a proof of concept for the importance of age in dopaminergic and serotonergic genetic association analyses. Our findings are consistent with the idea that genetic and neurocognitive mechanisms underlying ADHD may change throughout life. © 2015 Wiley Periodicals, Inc.

Continuity of genetic and environmental influences on cognition across the life span: a meta-analysis of longitudinal twin and adoption studies

The longitudinal rank-order stability of cognitive ability increases dramatically over the life span. Theoretical perspectives differ in their emphasis on genetic mechanisms in explaining the longitudinal stability of cognition and how stability changes with development. However, the patterns of stability of genetic and environmental influences on cognition over the life span remain poorly understood. We searched for longitudinal studies of cognition that reported raw genetically informative longitudinal correlations or parameter estimates from longitudinal behavior genetic models. We identified 150 combinations of time points and measures from 15 independent longitudinal samples. In total, longitudinal data came from 4,548 monozygotic twin pairs raised together, 7,777 dizygotic twin pairs raised together, 34 monozygotic twin pairs raised apart, 78 dizygotic twin pairs raised apart, 141 adoptive sibling pairs, and 143 nonadoptive sibling pairs, ranging in age from infancy through late adulthood. At all ages, cross-time genetic correlations and shared environmental correlations were substantially larger than cross-time nonshared environmental correlations. Cross-time correlations for genetic and shared environmental components were, respectively, low and moderate during early childhood, increased sharply over child development, and remained high from adolescence through late adulthood. Cross-time correlations for nonshared environmental components were low across childhood and gradually increased to moderate magnitudes in adulthood. Increasing phenotypic stability over child development was almost entirely mediated by genetic factors. Time-based decay of genetic and shared environmental stability was more pronounced earlier in child development. Results are interpreted in reference to theories of gene-environment correlation and interaction.

Executive function in MCDD and PDD-NOS: a study of inhibitory control, attention regulation and behavioral adaptivity

A proportion of children within the autism spectrum is at risk for severe deregulation of thought, emotion and behaviour resulting in (symptoms of) psychotic disorders over the course of development. In an attempt to identify this subgroup, children with PDD-NOS, subtype MCDD (n = 24) were compared to children with PDD-NOS (n = 23) on executive function (EF) skills. Significant differences emerged, always to the disadvantage of the children with PDD-NOS, subtype MCDD on various EF measures. The findings suggest compromised attention regulation and impaired inhibitory control in children with MCDD, which may help explain high levels of thought problems which are frequently observed in these children. Our findings provide evidence for recognizing a PDD subcategory of MCDD that is of specific interest with regard to long-term developmental risks involved.

Genetic and environmental influences on individual differences in emotion regulation and its relation to working memory in toddlerhood

This is the first study to explore genetic and environmental contributions to individual differences in emotion regulation in toddlers, and the first to examine the genetic and environmental etiology underlying the association between emotion regulation and working memory. In a sample of 304 same-sex twin pairs (140 MZ, 164 DZ) at age 3, emotion regulation was assessed using the Behavior Rating Scale of the Bayley Scales of Infant Development (BRS; Bayley, 1993), and working memory was measured by the visually cued recall (VCR) task (Zelazo, Jacques, Burack, & Frye, 2002) and several memory tasks from the Mental Scale of the BSID. Based on model-fitting analyses, both emotion regulation and working memory were significantly influenced by genetic and nonshared environmental factors. Shared environmental effects were significant for working memory, but not for emotion regulation. Only genetic factors significantly contributed to the covariation between emotion regulation and working memory.

Using an adoption design to separate genetic, prenatal, and temperament influences on toddler executive function

Poor executive functioning has been implicated in children's concurrent and future behavioral difficulties, making work aimed at understanding processes related to the development of early executive function (EF) critical for models of developmental psychopathology. Deficits in EF have been associated with adverse prenatal experiences, genetic influences, and temperament characteristics. However, our ability to disentangle the predictive and independent effects of these influences has been limited by a dearth of genetically informed research designs that also consider prenatal influences. The present study examined EF and language development in a sample of 361 toddlers who were adopted at birth and reared in nonrelative adoptive families. Predictors included genetic influences (as inherited from birth mothers), prenatal risk, and growth in child negative emotionality. Structural equation modeling indicated that the effect of prenatal risk on toddler effortful attention at age 27 months became nonsignificant once genetic influences were considered in the model. In addition, genetic influences had unique effects on toddler effortful attention. Latent growth modeling indicated that increases in toddler negative emotionality from 9 to 27 months were associated with poorer delay of gratification and poorer language development. Similar results were obtained in models incorporating birth father data. Mechanisms of intergenerational transmission of EF deficits are discussed.

Speed isn't everything: complex processing speed measures mask individual differences and developmental changes in executive control

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of 'processing speed' may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive control and resulting in overestimation of processing speed contributions to cognition. This concern may apply particularly to studies of developmental change, as even seemingly simple processing speed measures may require executive processes to keep children and older adults on task. We report two new studies and a re-analysis of a published study, testing predictions about how different processing speed measures influence conclusions about executive control across the lifespan. We find that the choice of processing speed measure affects the relationship observed between processing speed and executive control, in a manner that changes with age, and that choice of processing speed measure affects conclusions about development and the relationship among executive control measures. Implications for understanding processing speed, executive control, and their development are discussed.

The Young Netherlands Twin Register (YNTR): longitudinal twin and family studies in over 70,000 children

The Netherlands Twin Register (NTR) began in 1987 with data collection in twins and their families, including families with newborn twins and triplets. Twenty-five years later, the NTR has collected at least one survey for 70,784 children, born after 1985. For the majority of twins, longitudinal data collection has been done by age-specific surveys. Shortly after giving birth, mothers receive a first survey with items on pregnancy and birth. At age 2, a survey on growth and achievement of milestones is sent. At ages 3, 7, 9/10, and 12 parents and teachers receive a series of surveys that are targeted at the development of emotional and behavior problems. From age 14 years onward, adolescent twins and their siblings report on their behavior problems, health, and lifestyle. When the twins are 18 years and older, parents are also invited to take part in survey studies. In sub-groups of different ages, in-depth phenotyping was done for IQ, electroencephalography , MRI, growth, hormones, neuropsychological assessments, and cardiovascular measures. DNA and biological samples have also been collected and large numbers of twin pairs and parents have been genotyped for zygosity by either micro-satellites or sets of short nucleotide polymorphisms and repeat polymorphisms in candidate genes. Subject recruitment and data collection is still ongoing and the longitudinal database is growing. Data collection by record linkage in the Netherlands is beginning and we expect these combined longitudinal data to provide increased insights into the genetic etiology of development of mental and physical health in children and adolescents.

Attention-deficit/hyperactivity disorder genomics: update for clinicians

Attention deficit, hyperactivity disorder (ADHD) is familial and highly heritable. Several candidate genes involved in neurotransmission have been identified, however these confer minimal risk, suggesting that for the most part, ADHD is not caused by single common genetic variants. Advances in genotyping enabling investigation at the level of the genome have led to the discovery of rare structural variants suggesting that ADHD is a genomic disorder, with potentially thousands of variants, and common neuronal pathways disrupted by numerous rare variants resulting in similar ADHD phenotypes. Heritability studies in humans also indicate the importance of epigenetic factors, and animal studies are deciphering some of the processes that confer risk during gestation and throughout the post-natal period. These and future discoveries will lead to improved diagnosis, individualized treatment, cures, and prevention. These advances also highlight ethical and legal issues requiring management and interpretation of genetic data and ensuring privacy and protection from misuse.

The dopamine receptor D4 7-repeat allele influences neurocognitive functioning, but this effect is moderated by age and ADHD status: an exploratory study

OBJECTIVES

Evidence suggests the involvement of the dopamine D4 receptor gene (DRD4) in the pathogenesis of ADHD, but the exact mechanism is not well understood. Earlier reports on the effects of DRD4 polymorphisms on neurocognitive and neuroimaging measures are inconsistent. This study investigated the functional consequences of the 7-repeat allele of DRD4 on neurocognitive endophenotypes of ADHD in the Dutch subsample of the International Multicenter ADHD Genetics study.

METHODS

Participants were 350 children (5-11.5 years) and adolescents (11.6-19 years) with ADHD and their 195 non-affected siblings. An overall measure of neuropsychological functioning was derived by principal component analysis from five neurocognitive and five motor tasks. The effects of DRD4 and age were examined using Linear Mixed Model analyses.

RESULTS

The analyses were stratified for affected and non-affected participants after finding a significant three-way interaction between ADHD status, age and the 7-repeat allele. Apart from a main effect of age, a significant interaction effect of age and DRD4 was found in non-affected but not in affected participants, with non-affected adolescent carriers of the 7-repeat allele showing worse neuropsychological performance. In addition, carrying the 7-repeat allele of DRD4 was related to a significantly worse performance on verbal working memory in non-affected siblings, independent of age.

CONCLUSIONS

These results might indicate that the effect of the DRD4 7-repeat allele on neuropsychological functioning is dependent on age and ADHD status.

Social factors in the development of early executive functioning: a closer look at the caregiving environment

This study investigated prospective links between quality of the early caregiving environment and children's subsequent executive functioning (EF). Sixty-two families were met on five occasions, allowing for assessment of maternal interactive behavior, paternal interactive behavior, and child attachment security between 1 and 2 years of age, and child EF at 2 and 3 years. The results suggested that composite scores of parental behavior and child attachment were related to child performance on EF tasks entailing strong working memory and cognitive flexibility components (conflict-EF). In particular, child attachment security was related to conflict-EF performance at 3 years above and beyond what was explained by a combination of all other social antecedents of child EF identified thus far: child verbal ability and prior EF, family SES, and parenting behavior. Attachment security may thus play a meaningful role in young children's development of executive control.

Developmental trajectories in toddlers' self-restraint predict individual differences in executive functions 14 years later: a behavioral genetic analysis

We examined whether self-restraint in early childhood predicted individual differences in 3 executive functions (EFs; inhibiting prepotent responses, updating working memory, and shifting task sets) in late adolescence in a sample of approximately 950 twins. At ages 14, 20, 24, and 36 months, the children were shown an attractive toy and told not to touch it for 30 s. Latency to touch the toy increased with age, and latent class growth modeling distinguished 2 groups of children that differed in their latencies to touch the toy at all 4 time points. Using confirmatory factor analysis, we decomposed the 3 EFs (measured with latent variables at age 17 years) into a Common EF factor (isomorphic to response inhibition ability) and 2 factors specific to updating and shifting. Less-restrained children had significantly lower scores on the Common EF factor, equivalent scores on the Updating-Specific factor, and higher scores on the Shifting-Specific factor than did the more-restrained children. The less-restrained group also had lower IQ scores, but this effect was entirely mediated by the EF components. Twin models indicated that the associations were primarily genetic in origin for the Common EF variable but split between genetics and nonshared environment for the Shifting-Specific variable. These results suggest a biological relation between individual differences in self-restraint and EFs, one that begins early in life and persists into late adolescence.

Misattribution of facial expressions of emotion in adolescents at increased risk of psychosis: the role of inhibitory control

BACKGROUND

By studying behavior, cognitive abilities and brain functioning in adolescents at high risk for psychosis, we can gain an insight into the vulnerability markers or protective factors in the development of psychotic symptoms. Although many high-risk studies have focused on impairments in neurocognitive functions, such as memory and attention, very few studies have investigated problems in processing social cues such as facial expressions as a possible vulnerability marker for psychosis.

METHOD

Thirty-six adolescents at ultra-high risk (UHR) for psychosis and 21 non-clinical controls completed a face recognition test, a facial affect labeling test and an inhibitory control test. Schizotypal traits and schizophrenia symptoms were assessed using a schizotypy questionnaire and the Positive and Negative Syndrome Scale (PANSS).

RESULTS

The UHR group showed impairments in labeling facial expressions of others, in addition to a spared ability to recognize facial identity. More specifically, the UHR group made more errors in labeling neutral expressions compared to the controls, and an analysis of error types indicated that neutral faces were misattributed as being angry. The degree of misattribution of neutral-as-angry faces correlated significantly with reduced inhibitory control.

CONCLUSIONS

Our findings suggest that misattributing social cues might contribute to vulnerability for psychosis. This social cognitive deficit may be related to problems in inhibitory control, which potentially plays an important role in the selection of appropriate social meaning. These findings may have relevance for understanding the mechanisms underlying prodromal social dysfunction, which should be targeted in future remediation interventions.

The relation between ADHD symptoms and fine motor control: a genetic study

Previous research has shown that fine motor control (MC) performance, measured with a computerized task, was less accurate in children with ADHD and in their unaffected siblings, compared to healthy children. This might indicate a shared genetic etiology between MC and ADHD; it was therefore suggested that MC could serve as endophenotype for ADHD. We examined the association between ADHD symptoms (AS) and MC in a genetically informative design that can distinguish between a genetic and a nongenetic familial etiology for the association. Participants were 12-year-old twins and their siblings (N = 409). AS were rated on a continuous scale with the Strengths and Weaknesses of ADHD and Normal behavior scale (SWAN). MC accuracy and stability was measured with the computerized pursuit task of the Amsterdam Neuropsychological Tasks (ANT). Analyses were performed with Structural Equation Modelling. AS were weakly associated with MC accuracy of the left and right hand (r = -.10/-.10). No association with MC stability was found (r = -.01/-.03). AS were highly heritable (75%), while MC accuracy of the right hand and MC stability showed no genetic influences. For MC accuracy of the left hand, variance was explained by genetic (10%), common environmental (23%), and unique environmental variances. The association between MC accuracy of the left hand and AS was explained by a shared genetic influence but the genetic correlation was low (r = -.14). The phenotypic and genetic associations between AS and computerized MC were weak, suggesting that fine MC is not a proper endophenotype for ADHD.

Emotional Faces Capture Spatial Attention in 5-Year-Old Children

Emotional facial expressions are important social cues that convey salient affective information. Infants, younger children, and adults all appear to orient spatial attention to emotional faces with a particularly strong bias to fearful faces. Yet in young children it is unclear whether or not both happy and fearful faces extract attention. Given that the processing of emotional faces is believed by some to serve an evolutionarily adaptive purpose, attentional biases to both fearful and happy expressions would be expected in younger children. However, the extent to which this ability is present in young children and whether or not this ability is genetically mediated is untested. Therefore, the aims of the current study were to assess the spatial-attentional properties of emotional faces in young children, with a preliminary test of whether this effect was influenced by genetics. Five-year-old twin pairs performed a dot-probe task. The results suggest that children preferentially direct spatial attention to emotional faces, particularly right visual field faces. The results provide support for the notion that the direction of spatial attention to emotional faces serves an evolutionarily adaptive function and may be mediated by genetic mechanisms.

Genetic covariance structure of the four main features of borderline personality disorder

The patient population of borderline personality disorder (BPD) is heterogeneous; many different combinations of BPD symptoms can lead to a BPD diagnosis. We investigated to what extent the covariance among four main components of BPD is explained by shared genetic and environmental factors. Using an extended twin design, multivariate genetic models were applied to the scales of the PAI-BOR, a self-report questionnaire tapping four main features of BPD (affective instability, identity problems, negative relationships, and self-harm). Data on the four BPD scales were available for 5,533 twins and 1,202 siblings from the Netherlands, Belgium, and Australia. The correlations among the scales ranged from 0.23 to 0.50 and were best explained by a genetic common pathway model. This model specifies that genes and environment influence the covariance between four main features of BPD in qualitatively similar ways, through a single latent factor representing the BPD construct. The heritability of the latent BPD factor was 51% and the remainder of its variance was explained by unique environmental influences. For each BPD scale, except self-harm, around 50% of its variance was explained by the latent BPD factor. The remaining variance for each of the four scales was explained by genetic (4% for affective instability to 20% for self-harm) and environmental (38% for negative relationships to 67% for self-harm) factors that were specific to each scale.

Survivors of pediatric posterior fossa tumors: cognitive outcome, intervention, and risk-based care

Adolescent and young adult survivors of posterior fossa tumors face a wide variety of functional challenges following treatment. The concept of survival needs to include plans to regularly monitor and effectively respond to those patients considered at risk for continued morbidities associated with cancer and its treatment. The nature of impairment experienced by survivors is discussed, including predominant patient- and treatment-related risk factors. A model to respond to the cognitive needs of survivors, including risk-based evaluation and intervention, is proposed. It is imperative for the success of the survivor that a team approach is taken to care. This approach must include improving the awareness and education of teachers and other education specialists who interact with this population of survivors. There is also an obligation to put forth effort in developing and validating efficacious intervention programs.

Neurocognitive function profile in HIV-infected school-age children

OBJECTIVES

Evaluation of neurocognitive function of school-age children with HIV.

DESIGN

Cross-sectional observational study.

METHODS

Twenty-two children (median age 9.46 years) with perinatally acquired HIV infection were administered a global intelligence test and tests from the Amsterdam Neuropsychological Tasks (ANT) program. The relationship between various patient-, disease- and treatment factors and neurocognitive outcome variables was examined.

RESULTS

Compared with age-appropriate norms, mean IQ of the HIV-infected children was in the average range. However, the HIV-infected children performed poorer on several neuropsychological tests compared with age-appropriate norms. Executive function (attentional flexibility, visuospatial working memory) and processing speed emerged as the most sensitive cognitive measures in relation to HIV disease. The correlational analyses resulted in only two significant outcomes, showing that higher CD4% at initiation of highly active antiretroviral therapy (HAART) and longer treatment duration were associated with better working memory function and attentional control, respectively.

CONCLUSIONS

These exploratory data suggest that subtle neurocognitive impairments may exist in HIV-infected school-age children, in particular characterized by compromised executive function and slowed information processing. Further research with larger sample sizes is needed to confirm these findings.