Genetic and caregiving-based contributions to infant attachment: unique associations with distress reactivity and attachment security

Taking stock to move forward: Where the field of developmental psychopathology might be heading

In this paper, dedicated to Dante Cicchetti's contributions and enduring influence, we explore the prospective directions of developmental psychopathology. Our focus centers on key domains where Cicchetti's significant achievements have continually shaped our evolving thinking about psychological development. These domains include (a) the concepts of equifinality and multifinality, along with the challenges in predicting developmental trajectories, (b) the imperative to integrate wider sociocultural viewpoints into developmental psychopathology frameworks, (c) the interplay of genetic and environmental influences in developmental courses, (d) the significance of mental state language, and (e) the progress, or its absence, in the development of prevention and intervention tactics for children, adolescents, and their caregivers. While many of our forecasts regarding the future of developmental psychopathology may not materialize, we maintain optimistic that the essential ideas presented will influence the research agenda in this field and contribute to its growth over the next fifty years.

Genetics of adult attachment: An updated review of the literature

Attachment style, which has been theorized to be rooted in childhood bonding experiences, influences adult cognitive, emotional and interpersonal functioning. Despite its relationship with early experiences, research indicates that the continuity of attachment style across childhood and adulthood is only partial, being a malleable tendency that is shaped throughout development, with an increasing influence of genetics, as it occurs in other cognitive and behavioral phenotypes. Genetic research indicates that up to 45% of the variability in anxious and 39% in avoidant adult attachment style could be explained by genetic causes, but the precise mechanisms remain unclear. A narrative review is conducted analyzing the existing literature regarding the implication of candidate genes related to oxytocin, dopaminergic pathways, serotonergic pathways and brain-derived neurotrophic factor in adult attachment, with both vulnerability and differential susceptibility approaches, yielding mixed results. We highlight the lack of genome-wide studies and the scarcity of epigenetic investigation. Based on the existing data, we conclude that the genetics of adult attachment is an area that requires further research to clarify its etiological role and that it should be preferably approached as an interaction between nature and nurture.

Exploring Perinatal Indicators of Infant Social-Emotional Development: A Review of the Replicated Evidence

The importance of infant social-emotional development for outcomes across the lifecourse has been amply demonstrated. Despite this, most screening measures of social-emotional development are designed for children 18 months of age and over, with a clear gap in earlier infancy. No systematic review has yet harvested the evidence for candidate indicators in the perinatal window. This paper examines modifiable risk and protective factors for two seminal early markers of social-emotional development: attachment security and behavioral regulation mid-infancy. We searched meta-analytic and longitudinal studies of developmental relationships between modifiable exposures in the perinatal window (pregnancy to 10 months postpartum) and attachment and behavioral regulation status measured between 12 and 18 months. Six electronic databases were used: ERIC, PsycINFO, Medline Complete, Informit, Embase, and Scopus. Twelve meta-analytic reviews and 38 original studies found replicated evidence for 12 indicators across infant, caregiving, and contextual domains predictive of infant behavioral regulation and attachment status between 12 and 18 months. Key among these were caregiving responsiveness, maternal mental health, couple relationship, and SES as a contextual factor. Perinatal factors most proximal to the infant had the strongest associations with social-emotional status. Beyond very low birthweight and medical risk, evidence for infant-specific factors was weaker. Risk and protective relationships were related but not always inverse. Findings from this review have the potential to inform the development of reliable tools for early screening of infant social-emotional development for application in primary care and population health contexts.

Disentangling genes, attachment, and environment: A systematic review of the developmental psychopathology literature on gene-environment interactions and attachment

The role of genetics in relation to attachment is of continued interest to developmental psychology. Recent research has attempted to disentangle genetic main effects, environmental effects, and gene and environment (G × E) interactions in the development of attachment security/insecurity and disorganization. We systematically reviewed associations between gene markers and attachment, including G × E interactions, identifying 27 eligible studies. Inconsistent results emerged for associations between both gene effects and G × E interactions on attachment organization. Where G × E interactions used attachment as the environmental factor in the interaction, we observed more consistent results for differential susceptibility of G × E interactions on offspring behavior. Small sample size and heterogeneity in measurement of environmental factors impacted on comparability of studies. From these results, we propose that the future of research into the role of genetic effects in attachment lies in further exploration of G × E interactions, particularly where attachment acts as an environmental factor impacting on other child developmental outcomes emerging from the caregiving environment, consistent with differential susceptibility approaches to developmental psychopathology. In addition, from a methodological perspective, establishing the role of gene markers in such models will require a shift toward contemporary genomics, including genome-wide analysis (including novel genes and chromosomal loci), and epigenetic individual variations.

Genes and environment in attachment

In the last two decades, there has been increasing research interest in disentangling the contribution of genetic and environmental factors to individual differences in attachment, and in identifying the genes involved in shaping attachment. Twin studies suggest that as attachment changes during the course of development, genetic factors may play a progressively more important role, while shared environmental effects might decrease. However, most of this literature is limited by low power, measurement issues, and cross-sectional design. The findings of molecular genetic studies are, overall, inconclusive. The literature on main genetic effects and gene-by-environment interactions on attachment is filled with inconsistent and unreplicated findings. Also, most studies are underpowered. Challenges for future research are to identify the unshared environmental mechanisms involved in shaping attachment, and to better elucidate the genes involved and their interaction with the environment. Some pioneer studies suggested that the incorporation of epigenetic processes into G × E interaction models might represent a promising future way for investigating the complex, dynamic interplay between genes, environment, and attachment.

A Diagnosis of Denial: How Mental Health Classification Systems Have Struggled to Recognise Family Violence as a Serious Risk Factor in the Development of Mental Health Issues for Infants, Children, Adolescents and Adults

Child and adolescent mental health services (CAMHS) routinely overlook assessing for, and providing treatment to, infants and children living with family violence, despite family violence being declared endemic across the globe. As contemporary neuro-developmental research recognises the harm of being exposed to early relational trauma, key international diagnostic texts such as the DSM-5 and ICD-10 struggle to acknowledge or appreciate the relational complexities inherent in addressing family violence and its impacts during childhood. These key texts directly influence thinking, funding and research imperatives in adult services as well as CAMHS, however, they rarely reference family violence. Their emphasis is to pathologise conditions over exploring causality which may be attributable to relational violence. Consequently, CAMHS can miss important indicators of family violence, misdiagnose disorders and unwittingly, not address unacceptable risks in the child's caregiving environment. Notwithstanding urgent safety concerns, ongoing exposure to family violence significantly heightens the development of mental illness amongst children. CAMHS providers cannot and should not rely on current diagnostic manuals alone. They need to act now to see family violence as a significant and important risk factor to mental health and to treat its impacts on children before these develop into enduring neurological difficulties.

Further evidence of the limited role of candidate genes in relation to infant-mother attachment outcomes

In this paper, we examine the associations between specific candidate genes (DRD2, DRD4, COMT, biallelic and tri-allelic 5HTTLPR, and OXTR) and infant attachment outcomes as main effects and in conjunction with maternal sensitivity. The sample included 200 infants (97 European American, 94 African-American, and 9 biracial) and their mothers. Maternal sensitivity and overtly negative maternal behavior were observed when infants were 6 months and 1 year old in distress-eliciting contexts, attachment was assessed via the Strange Situation at age 1, and DNA samples were collected when children were 2 years old. Consistent with recent research in large samples, there was little evidence that these genes are associated with attachment security, disorganization, or distress as main effects (in additive, dominant, and homozygous models) or in conjunction with maternal sensitivity or overtly negative behavior (primarily dominance models). Furthermore, there was little evidence that associations vary as a function of race.

The Association Between Breastfeeding Duration and Attachment: A Genetically Informed Analysis

INTRODUCTION

A growing body of research explores whether breastfeeding during infancy influences the development of attachment security in offspring. Studies to date have generally yielded inconsistent results, with some studies detecting an association between breastfeeding and attachment security, and others failing to do so. The purpose of this study is to empirically consider whether (1) any association between breastfeeding and offspring attachment security is robust to both familial and genetic confounding and (2) whether the breastfeeding-attachment relationship is significant for both male and female offspring.

MATERIALS AND METHODS

The present study uses data from the Early Childhood Longitudinal Study: Birth Cohort (ECLS-B) to examine whether twins who differ in their extent of exposure to breastfeeding exhibit different attachment patterns by the time they reach toddlerhood.

RESULTS

The results suggest that, independent of genetic and shared environmental influences, breastfeeding duration increases the security of attachment in offspring, but only among females.

CONCLUSIONS

A longer duration of breastfeeding may help to facilitate a secure attachment among female offspring.

Epigenetic marks as the link between environment and development: examination of the associations between attachment, socioeconomic status, and methylation of the SLC6A4 gene

BACKGROUND

Epigenetic processes act as a link between environment and individual development. This pilot study examined the association between socioeconomic status (SES), attachment, and methylation of the promoter region of the serotonin transporter gene (SLC6A4).

METHODS

Attachment classification and SLC6A4 methylation was determined in 100 late adolescents. We hypothesized that (1) SES would interact with methylation to predict higher unresolved loss (UL) or trauma scores on the Adult Attachment Interview; (2) across SES, participants with unresolved attachment would have lower levels of methylation than organized or secure participants; and (3) within the unresolved classification, SES would predict methylation.

RESULTS

Results showed that lower methylation and low-SES were associated with higher UL, and higher methylation and low-SES were associated with higher unresolved trauma. Across SES, unresolved participants had lower levels of methylation than organized participants. Within the unresolved category, low-SES unresolved participants had higher levels of methylation than mid/upper-SES participants. SES was unrelated to methylation within the secure and organized categories.

CONCLUSIONS

These results suggest that the quality of attachment relationships may impact epigenetic processes.

Shedding light on the specificity of school-aged children's attachment narratives

A prominent research tradition within the field of attachment involves analyzing relationship narratives for qualities thought to reveal important information regarding the organization of attachment, and the different ways in which attachment insecurity presents. Researchers increasingly use this method to assess attachment in middle childhood, but further work needs to be conducted with respect to the divergent validity of attachment narratives in this age range. Thus, the current study examined differential associations between children's discursive style and linguistic behavior when completing an attachment interview (Child Attachment Interview [CAI]) and Non-Relational Interview (NRI). In addition, the discriminant validity of attachment narratives was assessed in predicting children's physiological reactivity to a relational challenge. Children (N = 125) completed the NRI and the CAI at Time 1. A subset of the original sample (n = 64) completed another assessment 1.5 years later involving simulated non-relational and relational challenges. While narrative coherence was moderately associated across the two interviews, CAI narrative coherence uniquely predicted reactivity to a relational probe. We discuss implications for understanding children's narrative styles across discourse topics as well as the significance of the results for using attachment interviews in this age range.

Attachment and Temperament Revisited: Infant Distress, Attachment Disorganization, and the Serotonin Transporter Polymorphism

OBJECTIVE

This study's aim was to evaluate whether infant disorganized attachment and infant proneness to distress exhibited differential relations to infant genetic factors as indexed by the serotonin transporter polymorphism.

BACKGROUND

The role of the short allele of the serotonin transporter polymorphism (5-HTTLPR) in enhancing sensitivity to fearful and negative affect has been well-established (Canli & Lesch, 2007). In the current study, we used this known property of the short allele to provide a test of an important postulate of attachment theory, namely that infant attachment security or disorganization is not a function of the infant's proneness to distress.

METHODS

Participants were 39 parents and infants assessed between 12 and 18 months in the Strange Situation procedure. Genotype categories for the 5-HTTLPR (and rs25531) were created by both the original and the reclassified grouping system; infant proneness to distress was assessed directly in the Strange Situation Procedure. We also assessed maternal behavior at 18 months to evaluate whether any observed genetic effect indicated a passive effect through the mother.

RESULTS

Consistent with previous findings, the 5-HTTLPR short allele was significantly related to the infant's wariness and distress, but was not related to attachment security or attachment disorganization. In addition, maternal disrupted interaction with the infant was not related to infant genotype or infant distress.

CONCLUSION

Results support the concept that infant proneness to distress is associated with serotonergic factors while infant attachment security or disorganization is not a function of either 5-HTTLPR or behaviorally rated proneness to distress.

Continuities and changes in infant attachment patterns across two generations

This study examined the intergenerational continuities and changes in infant attachment patterns within a higher-risk longitudinal sample of 55 female participants born into poverty. Infant attachment was assessed using the Strange Situation when participants were 12 and 18 months as well as several decades later with participants' children. Paralleling earlier findings from this sample on the stability of attachment patterns from infancy to young adulthood, results provided evidence for intergenerational continuities in attachment disorganization but not security. Children of adults with histories of infant attachment disorganization were at an increased risk of forming disorganized attachments. Although changes in infant attachment patterns across the two generations were not correlated with individuals' caregiving experiences or interpersonal stresses and supports during childhood and adolescence, higher quality social support during adulthood was associated with intergenerational changes from insecure to secure infant-caregiver attachment relationships.

Social stress regulation in 4-month-old infants: contribution of maternal social engagement and infants' 5-HTTLPR genotype

BACKGROUND

Maternal behavior and infant 5-HTTLPR polymorphism have been linked to infants' social stress reactivity and recovery at different ages. Nonetheless, Gene×Environment (G×E) studies focusing on early infancy are rare and have led to mixed results.

AIM

To investigate the contribution of maternal social engagement and infants' 5-HTTLPR polymorphism in predicting infants' negative emotionality in response to a social stressor, namely maternal unresponsiveness.

STUDY DESIGN

Cross-sectional, G×E study.

SUBJECTS

73 4-month-old infants and their mothers took part to the Face-to-Face Still-Face (FFSF) procedure.

OUTCOME MEASURES

A micro-analytical coding of negative emotionality was adopted to measure infants' reactivity to social stress (Still-Face episode) and infants' recovery after social stress (Reunion episode). Maternal contribution was measured as maternal social engagement during the Play episode. Infants were genotyped as S-carriers or L-homozygotes.

RESULTS

The interplay between maternal social engagement and infants' genotype was found to be predictive of infants' negative emotionality during both Still-Face and Reunion episodes of the FFSF paradigm. The interaction highlighted that maternal social engagement predicted minor negative emotionality during Still-Face and Reunion episodes for S-carrier infants, but not for L-homozygotes.

CONCLUSIONS

Findings extend previous results on adults and children, highlighting that maternal behavior might be a protective factor for stress reactivity and regulation, especially for S-carrier infants who are at risk for heightened stress susceptibility.

Genetic contributions to continuity and change in attachment security: a prospective, longitudinal investigation from infancy to young adulthood

BACKGROUND

Longitudinal research has demonstrated that individual differences in attachment security show only modest continuity from infancy to adulthood. Recent findings based on retrospective reports suggest that individuals' genetic variation may moderate the developmental associations between early attachment-relevant relationship experiences and adult attachment security. The purpose of this study was to use a prospective, longitudinal design to investigate genetic contributions to continuity and changes in attachment security from infancy to young adulthood in a higher risk sample.

METHODS

Infant attachment security was assessed using the Strange Situation Procedure at 12 and 18 months. Adults' general attachment representations were assessed using the Adult Attachment Interview at ages 19 and 26. Romantic attachment representations were assessed with the Current Relationship Interview (CRI) at ages 20-21 and ages 26-28. Individuals were genotyped for variants within the oxytocin receptor (OXTR), dopamine D4 receptor (DRD4), and serotonin transporter linked polymorphic region (5-HTTLPR).

RESULTS

The continuity of attachment security from infancy into young adulthood was consistently moderated by OXTR genetic variation. Infant attachment security predicted the security of adults' general and romantic attachment representations only for individuals with the OXTR G/G genotype. This interaction was significant when predicting adult attachment security as measured by the Adult Attachment Interview at ages 19 and 26 and the CRI at ages 26-28. Dopamine D4 receptor and 5-HTTLPR genetic variation did not consistently moderate the longitudinal associations between attachment security during infancy and adulthood.

CONCLUSIONS

This study provides initial longitudinal evidence for genetic contributions to continuity and change in attachment security from infancy to young adulthood. Genetic variation related to the oxytocin system may moderate the stability of attachment security across development.

Contributions of attachment theory and research: a framework for future research, translation, and policy

Attachment theory has been generating creative and impactful research for almost half a century. In this article we focus on the documented antecedents and consequences of individual differences in infant attachment patterns, suggesting topics for further theoretical clarification, research, clinical interventions, and policy applications. We pay particular attention to the concept of cognitive "working models" and to neural and physiological mechanisms through which early attachment experiences contribute to later functioning. We consider adult caregiving behavior that predicts infant attachment patterns, and the still-mysterious "transmission gap" between parental Adult Attachment Interview classifications and infant Strange Situation classifications. We also review connections between attachment and (a) child psychopathology; (b) neurobiology; (c) health and immune function; (d) empathy, compassion, and altruism; (e) school readiness; and (f) culture. We conclude with clinical-translational and public policy applications of attachment research that could reduce the occurrence and maintenance of insecure attachment during infancy and beyond. Our goal is to inspire researchers to continue advancing the field by finding new ways to tackle long-standing questions and by generating and testing novel hypotheses.

"He who sees things grow from the beginning will have the finest view of them" a systematic review of genetic studies on psychological traits in infancy

This paper reviews the studies that have aimed to identify genes influencing psychological traits in infancy (from birth to age 12 months). The review also addresses why genetic research in infancy is worthwhile and what genetic approaches such as genome-wide association studies and next generation sequencing could offer infant genetics. The results revealed that: (a) all studies (N=26) have employed a candidate gene association design; (b) existing studies have most commonly focused on the Dopamine receptor D4 (DRD4) and the Serotonin transporter promoter (5-HTTLPR) gene polymorphisms; (c) phenotypes that have been assessed are temperament, attachment, and attention. Two further studies included both temperament and electrophysiological markers; (d) among many unreplicated findings, the most promising result appeared to be an association between the long DRD4 polymorphism and several "positive" temperament characteristics from birth to 4-months of age and at 12-months of age. It is concluded that, to date, there are limited, and mixed, findings regarding the possible association of genes with psychological phenotypes in infancy.

Molecular-genetic correlates of infant attachment: a cautionary tale

This paper advises caution in relation to the increasing interest in molecular-genetic association studies in developmental psychology based on a set of empirical examples from the NICHD Study of Early Child Care and Youth Development (SECCYD) that highlight the fragility of effects reported in the literature on the molecular-genetic correlates of infant attachment. Specifically, this paper updates and provides three extensions to results reported in Luijk et al. (2011), which recently failed to replicate evidence from smaller-sample studies that a set of dopaminergic, serotonergic, and oxytonergic markers are significantly associated with infant attachment security or disorganization. First, we report here that the average effect of "usual suspect" polymorphisms on infant attachment security and disorganization in the SECCYD is approximately zero. Second, because Luijk et al. (2011) reported data based exclusively on the White infants in the SECCYD, this paper reveals that the average effect of polymorphisms featured in this literature is also of trivial magnitude in the non-White sub-sample (cf. Chen, Barth, Johnson, Gotlib, & Johnson, 2011). Third, this paper attempts, but fails, to replicate a recent finding by Raby et al. (2012) suggesting that, although molecular-genetic polymorphisms might not be implicated in security versus insecurity, the serotonin transporter gene contributes to variation in emotional distress during the Strange Situation Procedure. Implications for future research on the genetics of developmental phenotypes in general and attachment in particular are discussed, with a focus on statistical power and model-based theory testing.