Association of positive and negative parenting behavior with childhood ADHD: interactions with offspring monoamine oxidase A (MAO-A) genotype

Antecedents and Consequences of Child Externalizing Problems: Differences in Dynamic Parent-Child Processes

Given that noncompliance is the most common externalizing problem during middle childhood and reliably predicts significant conduct problems, innovations in elucidating its etiology are sorely needed. Evaluation of in-the-moment antecedents and consequences of child noncompliance improves traction on this goal, given that multiple theories contend that child noncompliance and parent behavior mutually influence each other through negative reciprocation as well as contingent praise processes. Among a sample of 140 families (child age: 6-10 years; 32.1% female), the present study capitalized on intensive repeated measures of observed child noncompliance and parent negative talk and praise objectively coded during three unique tasks. We employed dynamic structural equation modeling to evaluate within-dyad parent-child behavioral dynamics and between-dyad differences therein. Results provided mixed support for hypotheses and suggested that antecedents and consequences of child noncompliance differed according to task demands and child ADHD symptoms. Contrary to models of coercive cycles, during child-led play, parent negative talk was more likely following prior child noncompliance, but child noncompliance was less likely following prior parent negative talk. As expected, during parent-led play, parent praise was less likely following prior child noncompliance, which was also less likely following prior parent praise. Relative to youth with fewer symptoms, for children with elevated ADHD symptoms, during a challenging clean-up task, child noncompliance was less stable and less contingent on prior parent negative talk. Results are discussed in terms of their implications of real-time parent-child interactions for typical and atypical development of externalizing problems.

Parental rejection in early adolescence predicts a persistent ADHD symptom trajectory across adolescence

Despite a general decrease of attention-deficit/hyperactivity disorder (ADHD) symptoms during adolescence, these may persist in some individuals but not in others. Prior cross-sectional studies have shown that parenting style and their interaction with candidate genes are associated with ADHD symptoms. However, there is a lack of longitudinal research examining the independent and interactive effects of parenting and plasticity genes in predicting the course of attention-deficit/hyperactivity disorder (ADHD) symptoms across adolescence. Here, we investigated how children perceived their parents' parenting style (i.e., rejection, overprotection, and emotional warmth) at the age of 11, and their interaction with DRD4, MAOA, and 5-HTTLPR genotypes on parent-reported ADHD symptoms at three time points (mean ages 11.1, 13.4, and 16.2 years) in 1730 adolescents from the TRacking Adolescents' Individual Lives Survey (TRAILS). Growth Mixture Modeling in Mplus identified four ADHD symptom trajectories: low, moderate stable, high decreasing, and high persistent. Perceived parental rejection predicted class membership in the high persistent trajectory compared to the other classes (p < 0.001, odds ratios between 2.14 and 3.74). Gene-environment interactions were not significantly related to class membership. Our results indicate a role of perceived parental rejection in the persistence of ADHD symptoms. Perceived parental rejection should, therefore, be taken into consideration during prevention and treatment of ADHD in young adolescents.

Explaining the Prospective Association of Positive and Negative Parenting Behaviors and Child ADHD Symptoms: Pathways Through Child Executive Function and Reward Responsivity

Objective: Parenting behavior is a well-established correlate of offspring ADHD. However, little is known about how parenting exerts its effects on offspring ADHD symptomatology. We examined whether prospective associations between positive and negative parenting behaviors and child ADHD symptoms are mediated by deficits in child executive function (EF) and reward responsivity (RR). Method: One hundred and thirty-five children with and without ADHD were assessed across two Waves, when children were mean ages 6 and 8 respectively. Children completed tasks on EF, and parents completed questionnaires about their parenting behaviors and their children's RR and ADHD symptoms. Results: Negative parenting behavior at Wave 1 was indirectly associated with offspring ADHD symptoms at Wave 2 via offspring EF. Conclusion: Individual differences in EF, but not RR, during early childhood may constitute a potential pathway by which negative parenting behaviors exerts its effects on subsequent offspring ADHD symptomatology. Treatment implications are discussed.

Individual differences in sensitivity to positive home environment among children "at risk" for attention-deficit/hyperactivity disorder: A review

Although the evidence for the genetic basis of attention-deficit/hyperactivity disorder (ADHD) is strong, environmental factors, such as the quality of parenting or the home environment, may moderate such genetic liability. The plausible negative effect of a low-quality home environment and negative parenting on child outcomes is well-established; however, the positive effect of a high-quality environment and positive parenting remained largely uninvestigated. Due to the presence of genetic, temperamental, or physiological factors, children who were traditionally considered at-risk for ADHD may be more sensitive to aspects of their environment compared to children who are not at such risk. Therefore, they would be more affected by their environmental experience, either for good or bad. Under supportive environmental conditions, such at-risk individuals might actually outperform their non-vulnerable peers, suggesting that these individual factors might be considered susceptibility factors rather than risk factors. Little is known regarding the positive effect of the environment in the ADHD literature, but it has been demonstrated in cognitive functions that are closely associated with ADHD, such as executive functions (EF). We review this literature and examine the extant empirical support for sensitivity to aspects of the home environment and parenting in the case of ADHD and EF. Moreover, we review factors that could help identify the specific aspects of the home environment and parenting that these children might be more susceptible to. Such knowledge could be valuable when designing preventive interventions and identifying those children that are especially sensitive and could benefit from such interventions. Recommendations for future studies are discussed as well.

ADHD co-morbidities: A review of implication of gene × environment effects with dopamine-related genes

ADHD is a major burden in adulthood, where co-morbid conditions such as depression, substance use disorder and obesity often dominate the clinical picture. ADHD has substantial shared heritability with other mental disorders, contributing to comorbidity. However, environmental risk factors exist but their interaction with genetic makeup, especially in relation to comorbid disorders, remains elusive. This review for the first time summarizes present knowledge on gene x environment (GxE) interactions regarding the dopamine system. Hitherto, mainly candidate (GxE) studies were performed, focusing on the genes DRD4, DAT1 and MAOA. Some evidence suggest that the variable number tandem repeats in DRD4 and MAOA may mediate GxE interactions in ADHD generally, and comorbid conditions specifically. Nevertheless, even for these genes, common variants are bound to suggest risk only in the context of gender and specific environments. For other polymorphisms, evidence is contradictory and less convincing. Particularly lacking are longitudinal studies testing the interaction of well-defined environmental with polygenic risk scores reflecting the dopamine system in its entirety.

A Gene-Environment Interaction Study of Polygenic Scores and Maltreatment on Childhood ADHD

This study explored whether maltreatment moderates the association of polygenic risk for ADHD. Because individuals with low polygenic scores (PGS) for ADHD were previously shown to have better than expected functional outcomes (i.e., cognitive, mental health, social-emotional) than individuals with middle or high ADHD PGS, we hypothesized low ADHD PGS may confer a protective effect from maltreatment in the development of ADHD. Data were from participants with phenotypic and genotypic data in the National Longitudinal Study of Adolescent to Adult Health (Add Health; n = 4,722). ADHD PGS were generated from the most recent genome-wide association study on ADHD and categorized into three groups (i.e., low, medium, high) using empirically determined cut-points. A maltreatment factor score was derived from five forms of self-reported maltreatment experiences prior to age 18. ADHD PGS and maltreatment were positively associated with ADHD symptoms, as expected. However, no interaction between ADHD PGS and maltreatment on ADHD symptoms was detected. Despite the increase in predictive power afforded by PGS, the lack of an interaction between ADHD PGS and maltreatment on ADHD symptoms converges with an emerging body of PGS studies that have also failed to detect PGS-environment interplay in mental disorders. We discuss possible reasons for this pattern of results and offer alternative methods for future research in understanding gene-environment interactions.

Childhood parenting and adolescent internalizing and externalizing symptoms: Moderation by multilocus hypothalamic-pituitary-adrenal axis-related genetic variation

Genetic variants that regulate hypothalamic-pituitary-adrenal (HPA) axis function have been demonstrated to moderate the association between parenting and mental health. However, extant research has focused primarily on (i) effects of individual genes or (ii) maternal as opposed to paternal parenting. Using a multilocus genetic profile score (MGPS) approach, the current study is the first to examine the moderation effect of multilocus HPA-axis related genetic variants on the association of both maternal and paternal parenting with adolescent internalizing and externalizing symptoms. In a sample of 772 Chinese Han adolescents (Mage = 16.48 ± 1.40 years; 50.1% girls), a theory-driven MGPS was calculated using six polymorphisms within HPA-axis related genes (CRHR1, NR3C1, NR3C2, FKBP5, COMT, and HT1RA). Results showed that the MGPS interacted with both maternal and paternal parenting in the association with adolescent internalizing symptoms, but not externalizing symptoms. Consistent with the differential susceptibility model, adolescents with high versus low MGPS exhibited not only more internalizing symptoms when exposed to low quality of parenting but also less internalizing symptoms when exposed to high quality of parenting. The current findings highlight the potential value of using a multilocus approach to understanding gene-by-environment interaction (G×E) effects underlying mental health. Within such G×E effects, not only maternal but also paternal parenting should be addressed.

Review of rodent models of attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a polygenic neurodevelopmental disorder that affects 8-12 % of children and >4 % of adults. Environmental factors are believed to interact with genetic predispositions to increase susceptibility to ADHD. No existing rodent model captures all aspects of ADHD, but several show promise. The main genetic models are the spontaneous hypertensive rat, dopamine transporter knock-out (KO) mice, dopamine receptor subtype KO mice, Snap-25 KO mice, guanylyl cyclase-c KO mice, and latrophilin-3 KO mice and rats. Environmental factors thought to contribute to ADHD include ethanol, nicotine, PCBs, lead (Pb), ionizing irradiation, 6-hydroxydopamine, neonatal hypoxia, some pesticides, and organic pollutants. Model validation criteria are outlined, and current genetic models evaluated against these criteria. Future research should explore induced multiple gene KOs given that ADHD is polygenic and epigenetic contributions. Furthermore, genetic models should be combined with environmental agents to test for interactions.

A systematic review and meta-analysis examining the interrelationships between chemical and non-chemical stressors and inherent characteristics in children with ADHD

Children may be more vulnerable to the combined interactions of chemical and non-chemical stressors from their built, natural, and social environments when compared to adults. Attention deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed childhood neurodevelopmental disorder and is considered a major public health issue, as 75% of childhood cases persist into adulthood. ADHD is characterized by developmentally inappropriate levels of hyperactivity, impulsivity, and inattention, with the neurotransmitter serotonin regulating these symptoms. Monoamine oxidase A (MAOA) aids in serotonin uptake and is often implicated in behavioral and emotional disorders, including ADHD. When children are exposed to cigarette smoke, bisphenol A (BPA), or organophosphate pesticides, MAOA activity is inhibited. Non-chemical stressors, such as traumatic childhood experiences, and lifestyle factors, complicate the relationship between genotype and exposures to chemical stressors. But the co-occurrence among outcomes between exposures to chemical stressors, non-chemical stressors, and the low activity MAOA genotype suggest that mental illness in children may be influenced by multiple interacting factors. In this systematic review, we examine the existing literature that combines exposures to chemical and non-chemical stressors (specifically childhood trauma), MAOA characteristics, and ADHD diagnosis to investigate the interrelationships present. We observe that chemical (lead [Pb], phthalates/plasticizers, persistent organic pollutants, and cigarette smoke) exposure is significantly related to ADHD in children. We also observed that existing literature examining the interaction between MAOA, exposures to chemical stressors, and traumatic experiences and their effect on ADHD outcomes is sparse. We recommend that future studies investigating childhood ADHD include chemical and non-chemical stressors and inherent characteristics to gain a holistic understanding of childhood mental health outcomes.

Children's Reward and Punishment Sensitivity Moderates the Association of Negative and Positive Parenting Behaviors in Child ADHD Symptoms

Atypical reward processing, including abnormal reward responsivity and sensitivity to punishment, has long been implicated in the etiology of ADHD. However, little is known about how these facets of behavior interact with positive (e.g., warmth, praise) and negative (e.g., hostility, harsh discipline) parenting behavior in the early expression of ADHD symptoms in young children. Understanding the interplay between children's reward processing and parenting may be crucial for identifying specific treatment targets in psychosocial interventions for ADHD, especially given that not all children benefit from contingency-based treatments (e.g., parent management training). The study consisted of a sample of kindergarten children (N = 201, 55% male) and their parents, who completed questionnaires about their parenting practices, their child's behaviors and participated in an observed parent-child play task in the laboratory. Children's reward responsivity and sensitivity to punishment were positively associated with child ADHD symptoms. However, children with high reward responsivity had more symptoms of ADHD but only under conditions of low negative parenting (self-reported and observed) and high self-reported positive parenting, compared to children with low reward responsivity. Children with high sensitivity to punishment had more ADHD symptoms relative to children with low sensitivity to punishment, but only under conditions in which observed praise was infrequent. Results provide evidence that individual differences in sensitivity to reward/punishment may be an important of marker of risk for ADHD, but also highlights how children's responses to positive and negative parenting behavior may vary by children's sensitivities. Clinical and treatment implications are discussed.

Live fast, die young? A review on the developmental trajectories of ADHD across the lifespan

Attention-deficit/hyperactivity disorder (ADHD) is highly heritable and the most common neurodevelopmental disorder in childhood. In recent decades, it has been appreciated that in a substantial number of cases the disorder does not remit in puberty, but persists into adulthood. Both in childhood and adulthood, ADHD is characterised by substantial comorbidity including substance use, depression, anxiety, and accidents. However, course and symptoms of the disorder and the comorbidities may fluctuate and change over time, and even age of onset in childhood has recently been questioned. Available evidence to date is poor and largely inconsistent with regard to the predictors of persistence versus remittance. Likewise, the development of comorbid disorders cannot be foreseen early on, hampering preventive measures. These facts call for a lifespan perspective on ADHD from childhood to old age. In this selective review, we summarise current knowledge of the long-term course of ADHD, with an emphasis on clinical symptom and cognitive trajectories, treatment effects over the lifespan, and the development of comorbidities. Also, we summarise current knowledge and important unresolved issues on biological factors underlying different ADHD trajectories. We conclude that a severe lack of knowledge on lifespan aspects in ADHD still exists for nearly every aspect reviewed. We encourage large-scale research efforts to overcome those knowledge gaps through appropriately granular longitudinal studies.

DRD4 Variants Moderate the Impact of Parental Characteristics on Child Attention-Deficit Hyperactivity Disorder: Exploratory Evidence from a Multiplex Family Design

Parental ADHD symptomatology and related impairments have been robustly associated with youth ADHD across decades of work. Notably, these factors may impede typical development of child self-regulation capabilities through both neurobiological and interpersonal processes. High heritability of estimates for the disorder further suggest that these effects are likely genetically-mediated, at least in part. Variation within the dopamine D4 receptor gene (DRD4) has been shown to moderate parental influences on youth ADHD. Use of a multiplex family design (i.e., samples of families that included multiple affected members) may facilitate identification of additional gene variants of interest and advance understanding of gene-environment interplay in regard to parenting. Thirty multiplex families consisting of 114 individuals (66 youth, 48 parents) completed a multi-stage, multi-informant diagnostic and neurocognitive assessment, measures of parenting, and provided saliva samples for DNA analyses. Sanger sequencing of the DRD4 gene yielded 16 rare variants; a polygenic risk score was computed for both parents and youth. Generalized estimating equations (GEE) examined the predictive effects of parental ADHD symptoms, parental neurocognitive functioning, and poor parenting dimensions on youth ADHD as well as moderation of these effects by parental and youth DRD4 variants. Findings indicated that parental DRD4 variants moderated the impact of parental ADHD and neurocognitive functioning on youth ADHD symptoms. Youth DRD4 variants moderated the impact of parental inconsistent discipline on child ADHD. In all cases, stronger associations were observed for those individuals with more risk variants. These exploratory findings highlight the potential utility of a multiplex family design for examining the interplay between parent and child characteristics in predicting youth outcomes.

Dopamine receptor DRD4 gene and stressful life events in persistent attention deficit hyperactivity disorder

We performed a case-control association study in persistent ADHD considering eight candidate genes (DRD4, DAT1/SLC6A3, COMT, ADRA2A, CES1, CYP2D6, LPHN3, and OPRM1) and found additional evidence for the involvement of the Dup 120bp and VNTR 48bp functional variants within the dopamine receptor DRD4 gene in the etiology of adult ADHD. We subsequently investigated the interaction of stressful life events with these two DRD4 polymorphisms, and the impact of such events on the severity of ADHD symptomatology. The gene-by-environment analysis revealed an independent effect of stressful experiences on the severity of persistent ADHD, and a gene-by-environment interaction on the inattentive dimension of the disorder, where non carriers of the Dup 120bp (L) - VNTR 48bp (7R) haplotype were more sensitive to environmental adversity than carriers. These results are in agreement with previous works reporting a relationship between DRD4 and the effect of adverse experiences, which may explain the discordant findings in previous genetic studies and strengthen the importance of gene-by-environment interactions on the severity of ADHD. © 2015 Wiley Periodicals, Inc.

Item Response Theory Analysis of ADHD Symptoms in Children With and Without ADHD

Item response theory (IRT) was separately applied to parent- and teacher-rated symptoms of attention-deficit/hyperactivity disorder (ADHD) from a pooled sample of 526 six- to twelve-year-old children with and without ADHD. The dimensional structure ADHD was first examined using confirmatory factor analyses, including the bifactor model. A general ADHD factor and two group factors, representing inattentive and hyperactive/impulsive dimensions, optimally fit the data. Using the graded response model, we estimated discrimination and location parameters and information functions for all 18 symptoms of ADHD. Parent- and teacher-rated symptoms demonstrated adequate discrimination and location values, although these estimates varied substantially. For parent ratings, the test information curve peaked between -2 and +2 SD, suggesting that ADHD symptoms exhibited excellent overall reliability at measuring children in the low to moderate range of the general ADHD factor, but not in the extreme ranges. Similar results emerged for teacher ratings, in which the peak range of measurement precision was from -1.40 to 1.90 SD Several symptoms were comparatively more informative than others; for example, is often easily distracted ("Distracted") was the most informative parent- and teacher-rated symptom across the latent trait continuum. Clinical implications for the assessment of ADHD as well as relevant considerations for future revisions to diagnostic criteria are discussed.

Should we keep on? Looking into pharmacogenomics of ADHD in adulthood from a different perspective

A considerable proportion of adults with attention-deficit/hyperactivity disorder (ADHD) do not respond to the treatment with methylphenidate. This scenario could be due to inherited interindividual differences that may alter pharmacologic treatment response. In this sense, in 2012 we conducted a systematic search on PUBMED-indexed literature for articles containing information about pharmacogenomics of ADHD in adults. Five studies were found on methylphenidate pharmacogenomics and the only significant association was reported by one particular study. However, this single association with the SLC6A3 gene was not replicated in two subsequent reports. In the present review, although we could not find additional pharmacogenomics studies, we discuss these up-to-date findings and suggest new approaches for this field. Additionally, using systeomic-oriented databases, we provide a broad picture of new possible candidate genes as well as potential gene-gene interactions to be investigated in pharmacogenomics of persistent ADHD.

Parenting Behavior Mediates the Intergenerational Association of Parent and Child Offspring ADHD Symptoms

Although there are likely to be multiple mechanisms underlying parent attention-deficit/hyperactivity disorder (ADHD) symptoms as a key risk factor for offspring ADHD, potential explanatory factors have yet to be reliably identified. Given that parent ADHD symptoms independently predict parenting behavior and child ADHD symptoms, we tested whether individual differences in multiple dimensions of positive and negative parenting behavior (i.e., corporal punishment, inconsistent discipline, positive parenting behavior, observed negative talk, and observed praise) mediated the association between parental and offspring ADHD. We used a prospective design that featured predictors (i.e., parent ADHD symptoms) and mediators (i.e., parenting behavior) that temporally preceded the outcome (i.e., offspring ADHD symptoms). Using a well-characterized sample of 120 children with and without ADHD (ages 5-10 at Wave 1, 7-12 at Wave 2) and their biological parents, we examined multimethod (i.e., observed, self-report) measures of positive and negative parenting behavior as simultaneous mediators of the association of Wave 1 parent and Wave 2 offspring ADHD symptoms. Using a multiple mediation framework, consisting of rigorous bootstrapping procedures and controlling for parent depression, child's baseline ADHD and oppositional defiant disorder, and child's age, corporal punishment significantly and uniquely mediated the association of Wave 1 parent ADHD symptoms and Wave 2 offspring ADHD. We consider the role of parenting behavior in the intergenerational transmission of ADHD as well as implications of these findings for the intervention and prevention of childhood ADHD.

A biopsychosocial perspective on parenting and developmental psychopathology

Although considerable research has examined the relations between parental behavior and a range of child developmental outcomes, much of this work has been conducted at a very broad level of behavioral analysis. A developmental psychopathology framework and recent research conducted within this framework point to the need for models of parenting and child psychopathology that offer greater specificity regarding processes that may be implicated in the effects of these relationships. In addition, recent animal work and some human work has focused more on theproximalbiological and social mechanisms through which parenting affects child outcomes. Our conceptualization of parenting effects acknowledges that family and child factors are embedded in a dynamic biological and social context that is key to understanding developmental trajectories of child adjustment. In this paper, we review two areas of research that are illuminating the biological processes underlying links between parenting and child psychopathology: molecular genetics and psychophysiology. We adopt a biopsychosocial perspective on developmental psychopathology that implies that a set of hierarchically organized, but reciprocally interacting, processes, from the genetic to the environmental, provide the essential elements of both normative and nonnormative development (Gottlieb, 2007). New directions stimulated by this general approach are discussed, with an emphasis on the contextual and developmental issues and applications implied by such a perspective.

From depression to neurodegeneration and heart failure: re-examining the potential of MAO inhibitors

Initially introduced in the 1950s for treating depression, monoamine oxidase (MAO) inhibitors were gradually abandoned, mainly owing to their potential for drug-drug and drug-food interactions, the most widely known being with tyramine-containing food (the 'cheese' effect). Since then, more selective MAO-A or MAO-B inhibitors have been developed with substantially reduced risks, and have been approved for the treatment of depression and Parkinson's disease, respectively. Recent research suggests that some of these drugs also have neuroprotective properties, while preclinical evidence expands the spectrum of potential indications to heart failure, renal diseases and multiple sclerosis. In this article, the authors review the relevance of MAO isoforms to disease, and they also outline current research and development efforts in this class of drugs, including newer multipotent compounds.

Interaction of dopamine transporter gene and observed parenting behaviors on attention-deficit/hyperactivity disorder: a structural equation modeling approach

Emerging evidence suggests that some individuals may be simultaneously more responsive to the effects from environmental adversity and enrichment (i.e., differential susceptibility). Given that parenting behavior and a variable number tandem repeat polymorphism in the 3'untranslated region of the dopamine transporter (DAT1) gene are each independently associated with attention-deficit/hyperactivity disorder (ADHD), our goal was to evaluate the potential interactive effects of child DAT1 genotype with positive and negative parenting behaviors on childhood ADHD. We recruited an ethnically diverse sample of 150 six- to nine-year-old boys and girls with and without ADHD. Children were genotyped for a common polymorphism of the DAT1 gene, and objective counts of observed parenting behavior (i.e., negativity and praise) were obtained from a valid parent-child interaction task. Structural equation modeling was used to examine the interactive effects of DAT1 and observed parenting with a latent ADHD factor. We detected a significant interaction between observed praise and child DAT1 (coded additively), which suggested that praise was associated with increased ADHD, but only among youth with the 9/10 genotype. In addition, a marginally significant interaction between DAT1 (coded additively and recessively) and observed negativity emerged for ADHD, such that negativity was positively associated with ADHD but only for youth with the 9/9 genotype. Although differential susceptibility theory was not fully supported, these preliminary results suggest that interactive exchanges between parenting behavior and child genotype potentially contribute to the development of ADHD. Clinical implications for interactions between parenting behavior and child genotype are discussed.

How Do Interactions Between Early Caregiving Environment and Genes Influence Health and Behavior?

To promote optimal health and behavioral outcomes in children, nurses have long supported parents in providing the best possible care and nurturance to their offspring. A growing body of neuroscience research argues convincingly for the combined influences of genes and early caregiving on producing an individual's unique health and behavioral phenotype. In this article, we systematically review studies that demonstrate the relationship between qualities of early caregiving and genetic propensity to health and behavioral outcomes. From an initial set of 255 articles, 24 articles met our inclusion criteria. The outcomes fall into four distinct groups: hypothalamic-pituitary-adrenal (HPA) response to stress, externalizing behavior, internalizing behavior, and disorganized attachment. In the articles, authors examined genes that code for the 5-hydroxy tryptamine (serotonin) transporter genes linked polymorphic region [5- HTTLPR] serotonin transporter promoter, D4 dopamine receptor, brain-derived neurotrophic factor, and monoamine oxidase A promoter. The reviewed studies suggest that the effect of the early rearing environment on gene expression relates mainly to HPA response to stress, whereas interactions between genes and caregiving mainly relate to behavior and attachment. Findings have implications for nurses focused on advocacy, prevention, and intervention to support the healthy development of children in families faced with adversity.