Maartje P.C.M. Luijk

IQ of Children Growing Up in Children's Homes: A Meta-Analysis on IQ Delays in Orphanages

In this meta-analysis of 75 studies on more than 3,888 children in 19 different countries, the intellectual development of children living in childrens homes (orphanages) was compared with that of children living with their (foster) families. Children growing up in childrens homes showed lower IQs than did children growing up in a family (trimmed d = 0.74). The age at placement in the childrens home, the age of the child at the time of assessment, and the developmental level of the country of residence were associated with the size of the delays. Children growing up in childrens homes show a substantial lower level of IQ (average IQ of 84) than their peers reared in (foster) families (average IQ of 104), and the difference amounted to 20 IQ points. More research is needed to detect the causes of the large IQ delays and to test ways of improving the intellectual development of millions of children in orphanages around the world.

Dopaminergic, Serotonergic, and Oxytonergic Candidate Genes Associated with Infant Attachment Security and Disorganization? In Search of Main and Interaction Effects.

BACKGROUND AND METHODS In two birth cohort studies with genetic, sensitive parenting, and attachment data of more than 1,000 infants in total, we tested main and interaction effects of candidate genes involved in the dopamine, serotonin, and oxytocin systems (DRD4, DRD2, COMT, 5-HTT, OXTR) on attachment security and disorganization. Parenting was assessed using observational rating scales for parental sensitivity (Ainsworth, Bell, & Stayton, 1974), and infant attachment was assessed with the Strange Situation Procedure. RESULTS We found no consistent additive genetic associations for attachment security and attachment disorganization. However, specific tests revealed evidence for a codominant risk model for COMT Val158Met, consistent across both samples. Children with the Val/Met genotype showed higher disorganization scores (combined effect size d = .22, CI = .10-.34, p < .001). Gene-by-environment interaction effects were not replicable across the two samples. CONCLUSIONS This unexpected finding might be explained by a broader range of plasticity in heterozygotes, which may increase susceptibility to environmental influences or to dysregulation of emotional arousal. This study is unique in combining the two largest attachment cohorts with molecular genetic and observed rearing environment data to date.

Breastfeeding and its relation to maternal sensitivity and infant attachment.

Objective: To examine the association of breastfeeding with maternal sensitive responsiveness and infant-mother attachment security and disorganization. Methods: We included 675 participants of a prospective cohort study. Questionnaires about breastfeeding practices were administered at 2 and 6 months postpartum. At 14 months, maternal sensitive responsiveness was assessed in a 13-minute laboratory procedure using Ainsworths sensitivity scales, and attachment quality was assessed with the Strange Situation Procedure. Mothers were genotyped for oxytocin receptor genes OXTR rs53576 and OXTR rs2254298. Linear regressions and analyses of covariance adjusted for various background variables were conducted. We tested for mediation and moderation by maternal sensitive responsiveness and maternal oxytocin receptor genotype. Results: Continuous analyses showed that longer duration of breastfeeding was associated with more maternal sensitive responsiveness (B = 0.11, 95% confidence interval [CI] 0.02; 0.20, p < .05), more attachment security (B = 0.24, 95% CI = 0.02; 0.46, p < .05), and less attachment disorganization (B = −0.20, 95% CI −0.36; −0.03, p < .05). Duration of breastfeeding was not related to the risk of insecure-avoidant or insecure-resistant versus secure attachment classification, but longer duration of breastfeeding predicted a lower risk of disorganized versus secure attachment classification (n = 151; odds ratio [OR] = 0.81, 95% CI 0.66 to 0.99, p = .04). Maternal sensitive responsiveness did not mediate the associations, and maternal oxytocin receptor genotype was not a significant moderator. Conclusions: Although duration of breastfeeding was not associated with differences in infant-mother attachment classifications, we found subtle positive associations between duration of breastfeeding and sensitive responsiveness, attachment security, and disorganization.

FKBP5 and resistant attachment predict cortisol reactivity in infants: Gene—environment interaction

Quality of the parent-infant attachment relationship influences physiological stress regulation. Genetic factors also contribute to the stress regulatory HPA-axis. Quality of attachment as an index of the rearing environment (measured with the Strange Situation Procedure, SSP), and HPA-axis related SNPs (BclI, rs41423247; TthIIII, rs10052957; GR-9β, rs6198; N363S, rs6195; ER22/23EK, rs6189 and 6190; and FKBP5, rs1360780) were hypothesized to be related to cortisol reactivity in the stressful SSP. In this large population based sample, FKBP5 rs1360780, but not GR haplotype, was related to cortisol reactivity. Moreover, we found a significant interaction effect for insecure-resistant attachment and FKBP5 rs1360780, indicating a double-risk for heightened cortisol reactivity levels in infants with one or two T-alleles of the FKBP5 SNP and an insecure-resistant attachment relationship with their mother. Findings are discussed from the perspective of gene-environment interaction.

Infant Attachment, Parenting Stress, and Child Emotional and Behavioral Problems at Age 3 Years

SYNOPSIS Objective. To examine the role of infant attachment classification and parenting stress for toddler emotional and behavior problems. Design. Participants were 606 infant–mother dyads who took part in a population-based cohort study in the Netherlands. Infant–mother attachment classification was assessed using the Strange Situation Procedure when the children were 14 months old. At 18 months, parenting stress was measured with the Dutch version of the Parenting Stress Index. When the children were 3 years old, both mothers and fathers completed the Child Behavior Checklist. Results. Infant attachment moderated the effect of parenting stress on child emotional and behavior problems. Parenting stress was related to more aggression and attention problem behaviors in insecurely attached children, but not in securely attached children. Moreover, higher parenting stress was associated with more withdrawal problem behaviors in insecurely attached children, in particular in insecure-resistant and in disorganized children. Conclusion. In the presence of an insecure attachment relationship, more parenting stress is related to more (internalizing) withdrawal problem behavior and to more (externalizing) aggression and attention problems. Attachment security in infancy buffers the influence of parenting stress on child emotional and behavior problems.

Grandparental anxiety and depression predict young children's internalizing and externalizing problems: the generation R study.

BACKGROUND Family history is a major risk factor for child problem behaviour, yet few studies have examined the association between grandparental psychiatric disorder and child problem behaviour. Results are inconsistent as to whether the effect of grandparental depression on child problem behaviour is independent of parental psychopathology. METHODS Mothers and their children participated in an ethnically Dutch subcohort of a population-based prospective cohort in the Netherlands. N = 816 (66%) mothers and n = 691 fathers participated in the prenatal interviews. N = 687 (84%) mothers and children and n = 565 (82%) fathers participated three years postpartum. (Grand)parental psychopathology was assessed during pregnancy of the mothers with the Family Informant Schedule and Criteria (FISC), the Composite International Diagnostic Interview (CIDI) and the Brief Symptom Inventory (BSI). Child behaviour was assessed with the Child Behavior Checklist (CBCL) by mother and father when the child was three years old. RESULTS Grandparental anxiety disorder predicted maternal reports of childrens internalizing problems (OR = 1.98, 95% C.I. (1.20, 3.28), p-value<0.01) and externalizing problems (OR = 1.73, 95% C.I. (1.04, 2.87), p-value = 0.03), independent of parental psychopathology. Results were similar for grandparental depression; internalizing OR = 1.75, 95% C.I (1.11, 2.75), p-value = 0.02 and externalizing OR = 1.67, 95% C.I. (1.05, 2.64) p-value = 0.03. However, grandparental psychopathology was not associated with childrens problem behaviour as reported by the father. LIMITATIONS Information on grandparental lifetime psychiatric disorder was assessed through a parental interview which may have led to an underestimation of the prevalence rates. CONCLUSIONS These results confirm the importance of a family history including not only the parental but also the grandparental generations.

The association between parenting and attachment security is moderated by a polymorphism in the mineralocorticoid receptor gene: evidence for differential susceptibility.

Maternal sensitive responsiveness and extreme insensitivity only partly explain the variance in attachment security. Differences in attachment security may well be rooted in the interplay of genetic variations and environmental factors. The association between parenting (observed sensitive responsiveness and extreme insensitivity) and attachment security (assessed with the Strange Situation Procedure) was hypothesized to be moderated by genes involved in the regulation of the stress response: the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) genes. A significant G×E interaction was found: infants carrying the minor MR allele (G) were significantly more securely attached if their mothers showed more sensitive responsiveness and significantly less securely attached if their mothers showed more extremely insensitive behaviors. These associations were not significant for carriers of the AA genotype of MR. Findings are discussed from a differential susceptibility perspective.

Attachment insecurity predicts child active resistance to parental requests in a compliance task

AIM We studied the effects of early mother-child relationship quality and child temperament on the development of child compliance and active resistance in a large population-based cohort study (n = 534). BACKGROUND Parenting and the quality of the parent-child relationship can either hamper or support the development of child compliance directly or in interplay with child temperament. METHODS Mother-infant dyads were observed at 14 and 36 months and maternal and child behaviours were independently coded. The quality of compliance was assessed at 36 months in a clean-up task. Child behaviour was coded using a system differentiating between two dimensions: Compliance and Active Resistance. RESULTS Controlling for concurrent maternal sensitivity, child temperament, and gender children with a more insecure attachment relationship showed higher levels of active resistance during Clean-Up than more securely attached children. The effect was stronger for boys than for girls and mainly driven by attachment avoidance. CONCLUSIONS Early attachment is an important contributor to child socialization of moral behaviour.

Hours in non-parental child care are related to language development in a longitudinal cohort study

BACKGROUND The effects of child care services on several domains of child development have been extensively investigated, but evidence regarding the effects of child care on language development remains inconclusive. METHODS Within a large-scale population-based study, we examined the longitudinal associations between non-parental child care and language development from 1 to 6 years (n = 5375). RESULTS Results showed that more hours in non-parental child care were associated with better language abilities. However, more hours in care in the first year of life were associated with less language proficiency at ages 1 to 1.5. At later ages, this effect disappeared and language proficiency increased. Furthermore, children who spent more hours in centre-based care had better language scores than children in home-based care. Ethnicity, socio-economic status, gender or parity did not change these results. CONCLUSIONS This large, multi-ethnic study demonstrates beneficial effects of non-parental child care, particularly centre-based care, on language proficiency later in childhood.

Ethnic differences in prevalence and determinants of mother-child bed-sharing in early childhood.

BACKGROUND To date few studies have examined how multiple layers of influences shape the emergence of bed-sharing practices in the first 2 years postpartum. In our report, we examined bed-sharing in a large multiethnic sample, exploring the influences of three broad classes of influence on bed-sharing at single time points and across time: (1) sociodemographic and (2) contextual factors such as breastfeeding, maternal mental health and stress, and (3) child temperament and sleep habits. METHODS Frequencies of bed-sharing were assessed at two time points, 2 and 24 months, in a population-based multiethnic (Dutch, Turkish or Moroccan, and Caribbean) sample of 6309 children born in the Netherlands. RESULTS In Dutch mothers, the majority of mothers did not share their beds with their child, and bed-sharing rates decreased from 2 to 24 months. Other ethnic groups showed higher bed-sharing rates, typified by both increases in bed-sharing (the Turkish and Moroccan group) and persistence of bed-sharing over time (the Caribbean group). There were few family and child characteristics associated with bed-sharing in the non-Dutch ethnic groups. In contrast, bed-sharing in Dutch mothers was associated with child temperament and sleeping problems, maternal depression, and sociodemographic variables like crowding and maternal education. CONCLUSIONS Our results suggest that mothers with a Turkish and Moroccan or Caribbean background were more influenced by cultural values, whereas bed-sharing practices were more reactive in the Dutch group.