Elizabeth P. Hayden

Stability of laboratory-assessed temperamental emotionality traits from ages 3 to 7

A key component of temperament models is the presumed temporal stability of temperament traits. Although a substantial literature using parent report measures has addressed this claim, very few investigations have examined the stability of temperament using alternative measurement strategies, particularly those that involve direct assessment of emotional expressions. This study reports on the relative stability and heterotypic continuity of temperament traits measured via laboratory tasks and maternal report in a sample of children assessed at ages 3, 5, and 7, focusing on Positive Emotionality and Negative Emotionality. Relative stability of Positive Emotionality and Negative Emotionality traits ranged from moderate to high for laboratory and maternal report measures. Measures of emotional expressions exhibited levels of stability comparable to or higher than traits defined by other behavioral patterns (e.g., sociability and engagement).

The dopamine D2 receptor gene and depressive and anxious symptoms in childhood: associations and evidence for gene–environment correlation and gene–environment interaction

Objectives Research implicates the A1 allele of the dopamine D2 receptor gene (DRD2) Taq1A polymorphism in the development of depression and anxiety. Furthermore, recent papers suggest that children with A1 allele of this gene may receive less positive parenting, and that the effects of this gene on child symptoms may be moderated by parenting. We sought to replicate and extend these findings using behavioral measures in a nonclinical sample of young children. Methods In a sample of 473 preschool-aged children and their mothers, structured clinical interview measures and maternal reports of child symptoms were collected, and standardized observations of parent–child interactions were conducted. Results An association was detected between the DRD2 A1 allele and symptoms of depression and anxiety indexed using interview and parent report methods. As found in previous reports, children with the DRD2 A1 allele received less supportive parenting and displayed higher levels of negative emotionality during parent–child interactions. Tests of mediation and moderation were conducted. Conclusion We found associations between the DRD2 A1 allele and early-emerging anxious and depressive symptoms in a community sample of preschool-aged children, and evidence of a gene–environment correlation and moderation of the main effect of child genotype on child symptoms by parenting.

Interaction Between 5-HTTLPR and BDNF Val66Met Polymorphisms on HPA Axis Reactivity in Preschoolers

This study examined whether the interaction between the serotonin transporter promoter region (5-HTTLPR) and brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms was associated with hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. A community sample of 144 preschool-aged children was genotyped and exposed to stress-inducing laboratory tasks. Salivary cortisol was obtained at four time points during a standardized laboratory assessment before and after stressors involving separation from a parent and frustrating tasks. Children homozygous for the short-5-HTTLPR allele and carrying the Met-BDNF allele evidenced a significantly lower initial level of cortisol, followed by a positive increase in cortisol in response to the laboratory stressors. In contrast, children who were homozygous for the short-5-HTTLPR and the Val-BDNF alleles evidenced a greater decline in cortisol in response to the laboratory stressors. Findings indicated that the BDNF gene moderated the association between 5-HTTLPR and childrens biological stress responses, suggesting that epistatic effects play a role in individual differences in stress regulation, and possibly genetic vulnerability to stress-related disorders.

Decision making in bipolar disorder: A cognitive modeling approach

A formal modeling approach was used to characterize decision-making processes in bipolar disorder. Decision making was examined in 28 bipolar patients (14 acute and 14 remitted) and 25 controls using the Iowa Gambling Task (Bechara et al., 1994), a decision-making task used for assessing cognitive impulsivity. To disentangle motivational and cognitive aspects of decision-making processes, we applied a formal cognitive model to the performance on the Iowa Gambling Task. The model has three parameters: The relative impact of rewards and punishments on evaluations, the impact of recent and past payoffs, and the degree of choice consistency. The results indicated that acute bipolar patients were characterized by low choice consistency, or a tendency to make erratic choices. Low choice consistency improved the prediction of acute bipolar disorder beyond that provided by cognitive functioning and self-report measures of personality and temperament.

A Multimethod Investigation of the Behavioral Activation System in Bipolar Disorder

Dysregulation in behavioral activation system (BAS) activity has been implicated in the pathogenesis of bipolar disorder (BPD). To characterize BAS activity and related facets in this disorder, the authors compared 59 participants with BPD to 44 controls on multiple measures of BAS activity, including a standardized behavioral task, self-reports, and electroencephalographic indexes of regional cortical activity. Levels of putative BAS activity differed depending on assessment strategy. When a behavioral task indexing reward sensitivity was used, euthymic BPD patients showed evidence of higher BAS activity than either control participants or patients who were in a mood episode. Following a mood induction procedure designed to elicit BAS activity, currently episodic patients showed relatively greater left anterior cortical activity than either euthymic or control participants. Implications of the findings for future research on BPD vulnerability are described.

Assessing stress reactivity indexed via salivary cortisol in preschool-aged children

Identifying a stressor paradigm that elicits mean increases in salivary cortisol in young children has proven elusive, possibly due to characteristics of the paradigms used and how and when cortisol is sampled. We therefore examined the validity of a standardized task (adapted from Lewis and Ramsay, 2002) and procedures developed to assess cortisol reactivity in 215 preschool-aged children. Children participated in a standardized stress task during a home visit, which was videorecorded for future coding. Salivary cortisol samples were obtained at baseline and 10, 20, 30, 40, and 50 min post-stress. In support of the validity of the task, significant increases in cortisol levels from baseline were found, followed by a significant decline, and a quadratic function provided a good fit to the data. Children also showed a significant increase in negative emotions and a decrease in positive emotions over the course of the stress task. Results indicate that the task successfully elicited the hypothesized cortisol response in 3-year-old children.

The Role of Brain-Derived Neurotrophic Factor Genotype, Parental Depression, and Relationship Discord in Predicting Early-Emerging Negative Emotionality

The brain-derived neurotrophic factor (BDNF) gene is a plausible candidate for early-emerging negative emotionality (NE), and evidence suggests that the effects of this gene may be especially salient in the context of familial risk for child maladjustment. We therefore examined whether the single-nucleotide polymorphism producing a valine-to-methionine substitution at codon 66 (val66met) of the BDNF gene was associated with childhood NE, in the context of parental depression and relationship discord. A sample of 413 three-year-old children was assessed for NE using standardized laboratory measures. The children’s parents completed clinical interviews as well as a measure of marital satisfaction. Children with at least one BDNF methionine (met) allele exhibited elevated NE when a parent had a history of depressive disorder or when relationship discord was reported by a parent. In contrast, this allele was associated with especially low NE when parental depression was absent and when the parental relationship was not discordant. Our findings suggest that the BDNF met allele confers increased child sensitivity to both positive and negative familial influences.

Maternal Personality Influences the Relationship Between Maternal Reports and Laboratory Measures of Child Temperament

Previous research has indicated that agreement between maternal reports of child temperament and laboratory measures is modest; however, it is unclear whether maternal characteristics influence convergence between methods. We examined whether mothers’ personality influenced agreement between maternal reports and observational measures of child traits. A total of 64 mothers and children participated in this study. Maternal negative emotionality (NE) moderated the relationship between maternal reports and laboratory measures of child temperament: Greater convergence was found between maternal ratings of childrens negative emotional traits and laboratory measures for mothers with higher NE than mothers with lower NE. Findings are consistent with the possibility that mothers’ own traits influence the extent to which they successfully encode and/or report on analogous child behaviors.

Gender differences in young children's temperament traits: comparisons across observational and parent-report methods.

Evidence supporting the continuity between child temperament and adult personality traits is accumulating. One important indicator of continuity is the presence of reliable gender differences in traits across the lifespan. A substantial literature demonstrates gender differences on certain adult personality traits and recent meta-analytic work on child samples suggests similar gender differences for some broad and narrow domains of temperament. However, most existing studies of children rely only on parent-report measures. The present study investigated gender differences in temperament traits assessed by laboratory observation, maternal-report, and paternal-report measures. Across three independent samples, behavioral observations, maternal-report, and paternal-report measures of temperament were collected on 463 boys and 402 girls. Across all three methods, girls demonstrated higher positive affect and fear and lower activity level than boys. For laboratory measures, girls demonstrated higher levels of sociability and lower levels of overall negative emotionality (NE), sadness, anger and impulsivity than boys. However, girls demonstrated higher levels of overall NE and sadness than boys when measured by maternal reports. Finally, girls demonstrated lower levels of sociability based on paternal reports. Results are discussed in relation to past meta-analytic work and developmental implications of the findings.

Corticotropin-releasing hormone system polymorphisms are associated with children's cortisol reactivity.

The hypothalamic-pituitary-adrenal (HPA) axis underlies both adaptive and maladaptive responses to stress and may be an important marker of childhood vulnerability to psychopathology, although little is known about genetic variants that influence cortisol reactivity. We therefore examined associations between corticotrophin-releasing hormone (CRH) system gene (CRH, CRHR1 and CRHBP) variants and cortisol reactivity in preschoolers. A community sample of 409 three-year-old children completed a standardized stress task to elicit HPA axis activation. Salivary samples were obtained at the baseline and at 10-min intervals post-stress for a total of six samples. Salivary cortisol was measured using standard ELISA (enzyme-linked immunosorbent assay) protocols and cortisol reactivity was operationalized by calculating cortisol change scores ([baseline]-[peak cortisol post-stressor]). A single nucleotide polymorphism (SNP) marker panel containing 18 SNPs was used to tag the full-length CRH (4 SNPs), CRHR1 (7 SNPs) and CRHBP (7 SNPs) genes. Significant main effects on childrens cortisol reactivity (all ps<0.05) were found for loci on CRHR1 and CRHBP. Haplotypes of the CRHR1 linkage region were also associated with cortisol reactivity (all ps<0.01). Additionally, we found multiple interactions between tag-SNPs in all three gene-coding regions predicting cortisol reactivity (all ps<0.05). Individual differences in childrens cortisol reactivity are related to genetic variation in CRH system gene-coding regions. Our results have important implications for future research on the role of HPA axis function in the development of disorders such as anxiety and depression.