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Negative emotionality (NE) was evaluated as a candidate mechanism linking prenatal maternal affective symptoms and offspring internalizing problems during the preschool/early school age period. The participants were 335 mother–infant dyads from the Maternal Adversity, Vulnerability and Neurodevelopment project. A Confirmatory Bifactor Analysis (CFA) based on self-report measures of prenatal depression and pregnancy-specific anxiety generated a general factor representing overlapping symptoms of prenatal maternal psychopathology and four distinct symptom factors representing pregnancy-specific anxiety, negative affect, anhedonia and somatization. NE was rated by the mother at 18 and 36 months. CFA based on measures of father, mother, child-rated measures and a semistructured interview generated a general internalizing factor representing overlapping symptoms of child internalizing psychopathology accounting for the unique contribution of each informant. Path analyses revealed significant relationships among the general maternal affective psychopathology, the pregnancy- specific anxiety, and the child internalizing factors. Child NE mediated only the relationship between pregnancy-specific anxiety and the child internalizing factors. We highlighted the conditions in which prenatal maternal affective symptoms predicts child internalizing problems emerging early in development, including consideration of different mechanistic pathways for different maternal prenatal symptom presentations and child temperament.

Prenatal maternal depression and a multilocus genetic profile of two susceptibility genes implicated in the stress response were examined in an interaction model predicting negative emotionality in the first 3 years. In 179 mother–infant dyads from the Maternal Adversity, Vulnerability, and Neurodevelopment cohort, prenatal depression (Center for Epidemiologic Studies Depressions Scale) was assessed at 24 to 36 weeks. The multilocus genetic profile score consisted of the number of susceptibility alleles from the serotonin transporter linked polymorphic region gene (5-HTTLPR): no long-rs25531(A) (LA: short/short, short/long-rs25531(G) [LG], or LG/LG] vs. any LA) and the dopamine receptor D4 gene (six to eight repeats vs. two to five repeats). Negative emotionality was extracted from the Infant Behaviour Questionnaire—Revised at 3 and 6 months and the Early Child Behavior Questionnaire at 18 and 36 months. Mixed and confirmatory regression analyses indicated that prenatal depression and the multilocus genetic profile interacted to predict negative emotionality from 3 to 36 months. The results were characterized by a differential susceptibility model at 3 and 6 months and by a diathesis–stress model at 36 months.

The rising prevalence of internalizing problems in preschool/early school aged children across North America highlights the importance of understanding early etiology to inform treatment and prevention. The fetal programming hypothesis posits that exposure to adversity during pregnancy shapes later child development, and has informed research demonstrating that prenatal maternal affective psychopathology is associated with the development of childhood anxiety and depression. In a move toward understanding the development of internalizing psychopathology on an individual level, the goal of my dissertation is to examine different pathways underlying this relationship by focusing on the role of maternal and child biological and psychological factors. The temperamental trait negative emotionality (NE) and child genotype have been extensivity implicated in the pathway between prenatal maternal affective psychopathology and childhood internalizing problems, although the impact of their joint contribution is not well understood. Further, characteristics of maternal perinatal affect, specifically different symptom clusters are considered to understand their unique and combined influence on the child. Three different studies were conducted using a Canadian cohort part of the Maternal Adversity Vulnerability and Neurodevelopment project consisting of 590 mother-child dyads. Specific aims were outlined to achieve the overall goal. The first aim was to understand if certain children are differentially affected by fetal programming, specifically if there are children who are more biologically sensitive to maternal mood in utero. The first study investigated the influence of maternal prenatal and postnatal depression and a multi locus risk score consisting of the 5-HTTLPR and DRD4 genes on the development of infant and early childhood NE. Results indicated that prenatal maternal depression interacted with 5-HTTLPR and DRD4 to predict NE from 3-36 months. The second aim was to understand how the heterogeneous presentation of maternal mood may be linked with child emotion regulation. The second study investigated the influence of different symptom clusters of maternal pregnancy-specific anxiety and prenatal depression on early child internalizing symptoms, and if these relationships were mediated by early child NE. Pregnancy-specific anxiety was found to have a unique contribution above that of prenatal maternal depression on the development of preschool/early child internalizing problems, and this relationship was mediated by NE at 18-36 months. The third aim was to examine if fetal programming of infant NE and early child internalizing problems are part of the same developmental trajectory. The third study examined the influence of maternal prenatal affective psychopathology, early childhood NE and genetic susceptibility using two Polygenic Risk Scores (PRS) on early child internalizing problems in the same model through moderated mediating pathways. Child PRS score was found to moderate the relationship between prenatal maternal affective psychopathology and preschool/early child internalizing problems, although there was no moderated mediation in a model that also included early child NE. Results of all three aims are discussed in detail and integrated in a larger model that highlights four main pathways underlying the relationship between prenatal maternal affective psychopathology and child internalizing problems. Findings are interpreted as further evidence supporting fetal programming and clinical applications such as the importance of early screening and treatment for a range of maternal prenatal affective symptoms and continuous parenting support are discussed

Disorganized attachment is an important early risk factor for socioemotional problems throughout childhood and into adulthood. Prevailing models of the etiology of disorganized attachment emphasize the role of highly dysfunctional parenting, to the exclusion of complex models examining the interplay of child and parental factors. Decades of research have established that extreme child birth weight may have long-term effects on developmental processes. These effects are typically negative, but this is not always the case. Recent studies have also identified the dopamine D4 receptor ( DRD4 ) as a moderator of childrearing effects on the development of disorganized attachment. However, there are inconsistent findings concerning which variant of the polymorphism (seven-repeat long-form allele or non–seven-repeat short-form allele) is most likely to interact with caregiving in predicting disorganized versus organized attachment. In this study, we examined possible two- and three-way interactions and child DRD4 polymorphisms and birth weight and maternal caregiving at age 6 months in longitudinally predicting attachment disorganization at 36 months. Our sample is from the Maternal Adversity, Vulnerability and Neurodevelopment project, a sample of 650 mother–child dyads. Birth weight was cross-referenced with normative data to calculate birth weight percentile. Infant DRD4 was obtained with buccal swabs and categorized according to the presence of the putative allele seven repeat. Macroanalytic and microanalytic measures of maternal behavior were extracted from a videotaped session of 20 min of nonfeeding interaction followed by a 10-min divided attention maternal task at 6 months. Attachment was assessed at 36 months using the Strange Situation procedure, and categorized into disorganized attachment and others. The results indicated that a main effect for DRD4 and a two-way interaction of birth weight and 6-month maternal attention (frequency of maternal looking away behavior) and sensitivity predicted disorganized attachment in robust logistic regression models adjusted for social demographic covariates. Specifically, children in the midrange of birth weight were more likely to develop a disorganized attachment when exposed to less attentive maternal care. However, the association reversed with extreme birth weight (low and high). The DRD4 seven-repeat allele was associated with less disorganized attachment (protective), while non–seven-repeat children were more likely to be classified as disorganized attachment. The implications for understanding inconsistencies in the literature about which DRD4 genotype is the risk direction are also considered. Suggestions for intervention with families with infants at different levels of biological risk and caregiving risk are also discussed.

Prenatal maternal depression and a multilocus genetic profile of two susceptibility genes implicated in the stress response were examined in an interaction model predicting negative emotionality (NE) in the first 3 years. In 179 mother-infant dyads from the Maternal Adversity, Vulnerability and Neurodevelopment cohort, prenatal depression (CES-D) was assessed at 24 to 36 weeks. The multilocus genetic profile score consisted of the number of susceptibility alleles from 5-HTTLPR (No LA (S/S, S/LG or LG/LG) vs. any LA) and Dopamine Receptor D4 (6–8R vs. 2–5R). NE was extracted from the IBQ-R at 3 and 6 months and the ECBQ at 18 and 36 months. Mixed and confirmatory regression analyses indicated that prenatal depression and the multilocus genetic profile interacted to predict NE from 3 to 36 months. Results were characterised by a differential susceptibility model at 3 and 6 months and by a diathesis stress model at 36 months.

Individuals with Down syndrome are impaired in motor control, working memory and attention (Brown, et al., 2003; Jarrold & Baddeley, 2001; Lanfranchi, Jerman, Dal Pont, Alberti, & Vianello, 2010). These impairments may be related to a deficit in time perception as time perception is considered to be an important adaptive skill that contributes to many everyday tasks from motor control to language processing (Meck, 2005). Furthermore attention and working memory are hypothesized by the Scalar Expectancy Theory to influence time perception (Allan, 1998). Time perception of short durations (under one second) was examined in individuals with Down syndrome and typically developing (TD) children matched on mental age of approximately 5 years old. Temporal bisection and generalization tasks were used to examine basic perceptual timing mechanisms. For both tasks, the participants with Down syndrome demonstrated similar responding to making temporal judgment as the TD children. There was some indication that the persons with Down syndrome responded with lower temporal sensitivity than the TD children as the results from the repeated measure ANOVA indicated a marginally significant group by duration interaction (F(6, 168) = 2.15, p = .08) and the Weber Fraction for the individuals with Down syndrome was marginally significantly higher (t(28) = 4.75, p = .06). These findings may inform the current understanding of cognitive and motor impairment in Down syndrome and contribute to the current literature on time perception.