Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood

Translating basic research knowledge on the biological embedding of early-life stress into novel approaches for the developmental programming of lifelong health

This review integrates scientific knowledge obtained over the past few decades on the biological mechanisms that contribute to the profound association between exposure to early adversity, including childhood trauma and prenatal stress, and the lifelong elevated risk to develop a broad range of diseases. We further discuss insights into gene-environment interactions moderating the association between early adversity and disease manifestation and we discuss the role of epigenetic and other molecular processes in the biological embedding of early adversity. Based on these findings, we propose potential mechanisms that may contribute to the intergenerational transmission of risk related to early adversity from the mother to the fetus. Finally, we argue that basic research knowledge on the biological embedding of early adversity must now be translated into novel intervention strategies that are mechanism-driven and sensitive to developmental timing. Indeed, to date, there are no diagnostic biomarkers of risk or mechanism-informed interventions that we can offer to victims of early adversity in order to efficiently prevent or reverse adverse health outcomes. Such translational efforts can be expected to have significant impact on both clinical practice and the public health system, and will promote precision medicine in pediatrics and across the lifespan.

Trained Innate Immunity Not Always Amicable

The concept of „trained innate immunity" is understood as the ability of innate immune cells to remember invading agents and to respond nonspecifically to reinfection with increased strength. Trained immunity is orchestrated by epigenetic modifications leading to changes in gene expression and cell physiology. Although this phenomenon was originally seen mainly as a beneficial effect, since it confers broad immunological protection, enhanced immune response of reprogrammed innate immune cells might result in the development or persistence of chronic metabolic, autoimmune or neuroinfalmmatory disorders. This paper overviews several examples where the induction of trained immunity may be essential in the development of diseases characterized by flawed innate immune response.

Brain Magnetic Resonance Imaging Findings in Children after Antenatal Maternal Depression Treatment, a Longitudinal Study Built on a Pilot Randomized Controlled Trial

Antenatal depression is associated with an increased risk of offspring neuro-developmental disorders, potentially as a consequence of an altered brain development in utero. We hypothesized that reducing maternal depression by Cognitive Behavioral Therapy (CBT) during pregnancy may ameliorate the offspring’s brain (micro)structural outcomes. 54 pregnant women with a diagnosed clinical depression were randomly allocated to CBT or Treatment as Usual (TAU), showing moderate to large depression symptom improvements after CBT. In 16 of their children (69% boys, N(TAU) = 8, N(CBT) = 8, mean age = 5.9 years, range = 3.9–7.1 years) brain Magnetic Resonance Imaging (MRI) scans were conducted. Children from the CBT group had a thicker right lateral occipital cortex (difference: 0.13 mm, 95% CI = 0.005–0.26) and lingual gyrus (difference: 0.18 mm, 95% CI = 0.01–0.34). In the CBT group, Voxel-Based Morphometry analysis identified one cluster showing increased gray matter concentration in the right medial temporal lobe at p < 0.05 uncorrected, and fixel-based analysis revealed reduced fiber-bundle cross-section in the Fornix, the Optical Tract, and the Stria Terminalis at p < 0.01 uncorrected. However, none of the results survived correction for multiple testing. Our explorative analyses provided some indication that antenatal CBT for depression may ameliorate offspring’s brain (micro)structural outcomes, but the sample size was extremely small, and our results should be cautiously interpreted. Larger studies are warranted to confirm our preliminary conclusions that CBT for antenatal depression affects brain development in children.

Prenatal Maternal Stress, Child Cortical Thickness, and Adolescent Depressive Symptoms

Prenatal maternal stress predicts subsequent elevations in youth depressive symptoms, but the neural processes associated with these links are unclear. This study evaluated whether prenatal maternal stress is associated with child brain development, and adolescent depressive symptoms using a prospective design with 74 mother child pairs (40 boys). Maternal stress was assessed during pregnancy, child cortical thickness at age 7, and depressive symptoms at age 12. Prenatal maternal stress was associated with less cortical thickness primarily in frontal and temporal regions and with elevated depressive symptoms; child cortical thickness additionally correlated with adolescent depressive symptoms. The observed associations are consistent with the possibility that cortical thickness in superior frontal regions links associations between prenatal maternal stress and adolescent depressive symptoms.

Does Anhedonia Presage Increased Risk of Posttraumatic Stress Disorder? : Adolescent Anhedonia and Posttraumatic Disorders

Anhedonia, the reduced ability to experience pleasure, is a dimensional entity linked to multiple neuropsychiatric disorders, where it is associated with diminished treatment response, reduced global function, and increased suicidality. It has been suggested that anhedonia and the related disruption in reward processing may be critical precursors to development of psychiatric symptoms later in life. Here, we examine cross-species evidence supporting the hypothesis that early life experiences modulate development of reward processing, which if disrupted, result in anhedonia. Importantly, we find that anhedonia may confer risk for later neuropsychiatric disorders, especially posttraumatic stress disorder (PTSD). Whereas childhood trauma has long been associated with increased anhedonia and increased subsequent risk for trauma-related disorders in adulthood, here we focus on an additional novel, emerging direct contributor to anhedonia in rodents and humans: fragmented, chaotic environmental signals ("FRAG") during critical periods of development. In rodents, recent data suggest that adolescent anhedonia may derive from aberrant pleasure/reward circuit maturation. In humans, recent longitudinal studies support that FRAG is associated with increased anhedonia in adolescence. Both human and rodent FRAG exposure also leads to aberrant hippocampal function. Prospective studies are underway to examine if anhedonia is also a marker of PTSD risk. These preliminary cross-species studies provide a critical construct for future examination of the etiology of trauma-related symptoms in adults and for and development of prophylactic and therapeutic interventions. In addition, longitudinal studies of reward circuit development with and without FRAG will be critical to test the mechanistic hypothesis that early life FRAG modifies reward circuitry with subsequent consequences for adolescent-emergent anhedonia and contributes to risk and resilience to trauma and stress in adulthood.

Examining the relationship between perinatal depression and neurodevelopment in infants and children through structural and functional neuroimaging research

Depression is the most common perinatal psychiatric disorder, but little is known about how it may impact offspring neurodevelopment, as well as the mechanisms by which it may confer transgenerational psychiatric risk. This review presents imaging studies conducted to evaluate the relationship between perinatal depression (PND) and infant and child neurodevelopment. Altered structural and functional connectivity is implicated in children exposed to PND and anxiety. Overall, there are changes in connectivity between amygdala and the prefrontal cortex. Studies suggest decreased hippocampal growth in the first 6 months after birth, decreased cortical thickness in children, and increased amygdala volumes, that are more pronounced in female offspring. Future research is needed to understand the impact of PND on development so that early interventions which promote mother-infant bonding and cognitive development may improve developmental outcomes in children exposed to PND, reducing later risk of psychopathology.

The influence of unpredictable, fragmented parental signals on the developing brain

Mental illnesses originate early in life, governed by environmental and genetic factors. Because parents are a dominant source of signals to the developing child, parental signals - beginning with maternal signals in utero - are primary contributors to children's mental health. Existing literature on maternal signals has focused almost exclusively on their quality and valence (e.g. maternal depression, sensitivity). Here we identify a novel dimension of maternal signals: their patterns and especially their predictability/unpredictability, as an important determinant of children's neurodevelopment. We find that unpredictable maternal mood and behavior presage risk for child and adolescent psychopathology. In experimental models, fragmented/unpredictable maternal care patterns directly induce aberrant synaptic connectivity and disturbed maturation of cognitive and emotional brain circuits, with commensurate memory problems and anhedonia-like behaviors. Together, our findings across species demonstrate that patterns of maternal signals influence brain circuit maturation, promoting resilience or vulnerability to mental illness.

Does Prenatal Maternal Distress Contribute to Sex Differences in Child Psychopathology?

PURPOSE OF REVIEW

Prenatal maternal psychological distress is an established risk factor for the development of psychopathology in offspring. The purpose of this review is to evaluate whether sex differences in fetal responses to maternal distress contribute to sex differences in subsequent psychopathology.

RECENT FINDINGS

Male and female fetuses respond differently to stress signals. We review recent evidence that demonstrates a sex-specific pattern of association between prenatal maternal distress and pathways associated with risk for psychopathology including offspring hypothalamic pituitary adrenocortical (HPA) axis regulation, brain development, and negative emotionality. Prenatal maternal distress exerts sex-specific consequences on the fetus. These differences may contribute to the well-established sex differences in psychopathology and in particular to greater female vulnerability to develop internalizing problems.

Characterizing adverse prenatal and postnatal experiences in children

BACKGROUND

Prenatal and postnatal adversities, including prenatal alcohol exposure (PAE), prenatal exposure to other substances, toxic stress, lack of adequate resources, and postnatal abuse or neglect, often co-occur. These exposures can have cumulative effects, or interact with each other, leading to worse outcomes than single exposures. However, given their complexity and heterogeneity, exposures can be difficult to characterize. Clinical services and research often overlook additional exposures and attribute outcomes solely to one factor.

METHODS

We propose a framework for characterizing adverse prenatal and postnatal exposures and apply it to a cohort of 77 children. Our approach considers type, timing, and frequency to quantify PAE, other prenatal substance exposure, prenatal toxic stress, postnatal threat (harm or threat of harm), and postnatal deprivation (failure to meet basic needs) using a 4-point Likert-type scale. Postnatal deprivation and harm were separated into early (<24 months of age) and late (≥24 months) time periods, giving seven exposure variables. Exposures were ascertained via health records, child welfare records, interviews with birth parents, caregivers, and/or close family/friends.

RESULTS

Nearly all children had co-occurring prenatal exposures, and two-thirds had both prenatal and postnatal adversities. Children with high PAE were more likely to experience late postnatal adversities, and children with other prenatal substance exposure were more likely to have early postnatal deprivation. Postnatal adversities were more likely to co-occur.

CONCLUSION

This framework provides a comprehensive picture of a child's adverse exposures, which can inform assessment and intervention approaches and policy and will be useful for future research.

The Interplay Between Nutrition and Stress in Pregnancy: Implications for Fetal Programming of Brain Development

Growing evidence supports an important role for the intrauterine environment in shaping fetal development and subsequent child health and disease risk. The fetal brain is particularly plastic, whereby even subtle changes in structure and function produced by in utero conditions can have long-term implications. Based on the consideration that conditions related to energy substrate and likelihood of survival to reproductive age are particularly salient drivers of fetal programming, maternal nutrition and stress represent the most commonly, but independently, studied factors in this context. However, the effects of maternal nutrition and stress are context dependent and may be moderated by one another. Studies examining the effects of the bidirectional nutrition-stress interplay in pregnancy on fetal programming of brain development are beginning to emerge in the literature. This review incorporates all currently available animal and human studies of this interplay and provides a synthesis and critical discussion of findings. Nine of the 10 studies included here assessed nutrition-stress interactions and offspring neurodevelopmental or brain development outcomes. Despite significant heterogeneity in study design and methodology, two broad patterns of results emerge to suggest that the effects of prenatal stress on various aspects of brain development may be mitigated by 1) higher fat diets or increased intake and/or status of specific dietary fats and 2) higher dietary intake or supplementation of targeted nutrients. The limitations of these studies are discussed, and recommendations are provided for future research to expand on this important area of fetal programming of brain development.

Prenatal maternal anxiety and children's brain structure and function: A systematic review of neuroimaging studies

BACKGROUND

Maternal anxiety disorders are common during pregnancy and postpartum, and are associated with increased behaviour problems and risk of mental health difficulties in children. Understanding alterations in brain structure and function associated with maternal anxiety may help elucidate potential mechanisms via which high maternal anxiety could affect children.

METHODS

We conducted a systematic review of extant research studying the associations between prenatal anxiety and children's brain structure and function, as assessed through neuroimaging. Data were gathered in accordance with the PRISMA review guidelines.

RESULTS

Ten articles were identified, and all found a significant association between antenatal maternal anxiety and child neurodevelopment. Studies vary considerably in their methods with five studies employing electroencephalography (EEG), one using magnetoencephalography (MEG), and the rest employing magnetic resonance imaging (MRI).

LIMITATIONS

The heterogeneity of neuroimaging techniques undertaken by the reviewed studies precluded a meta-analysis from being performed. The applicability of this systematic review to clinical practice is also limited given that the studies examined children across a wide age range (neonates to 17 years).

CONCLUSIONS

From early infancy to late adolescence, findings suggest alterations of brain structure and function in frontal, temporal, and limbic areas in children born to mothers who experienced prenatal anxiety. These brain abnormalities may underlie associations between prenatal anxiety and children's behaviour, though more research incorporating neuroimaging and behavioural data is necessary to determine this.

Maternal psychological distress during pregnancy and childhood health outcomes: a narrative review

Maternal psychological distress is common in pregnancy and may influence the risk of adverse outcomes in children. Psychological distress may cause a suboptimal intrauterine environment leading to growth and developmental adaptations of the fetus and child. In this narrative review, we examined the influence of maternal psychological distress during pregnancy on fetal outcomes and child cardiometabolic, respiratory, atopic and neurodevelopment-related health outcomes. We discussed these findings from an epidemiological and life course perspective and provided recommendations for future studies. The literature in the field of maternal psychological distress and child health outcomes is extensive and shows that exposure to stress during pregnancy is associated with multiple adverse child health outcomes. Because maternal psychological distress is an important and potential modifiable factor during pregnancy, it should be a target for prevention strategies in order to optimize fetal and child health. Future studies should use innovative designs and strategies in order to address the issue of causality.

Children's stress regulation mediates the association between prenatal maternal mood and child executive functions for boys, but not girls

Prenatal exposure to maternal mood disturbances shapes children's cognitive development reflected in the critical construct of executive functions (EFs). Little is known, however, about underlying mechanisms. By examining cortisol responses in both everyday and lab challenge settings, we tested whether the child/offspring hypothalamic-pituitary-adrenal axis mediates effects of prenatal maternal mood on child EFs at age 6. In 107 Canadian children born to women with a wide range of anxious and depressive symptoms during pregnancy, we found that in boys but not girls, depressed and/or anxious prenatal maternal mood is associated with heightened diurnal cortisol levels in everyday settings, as well as heightened cortisol reactivity to a lab challenge and that this heightened reactivity was associated with poorer EFs. Among boys we also observed that cortisol reactivity but not diurnal cortisol mediated the association between depressed and/or anxious prenatal maternal mood and EFs. Depressed and/or anxious prenatal maternal mood was related to child EFs for both girls and boys. To our knowledge, this is the first study to demonstrate a mediating role for child stress regulation in the association between prenatal maternal stress-related mood disturbances and child EFs, providing evidence of a mechanism contributing to fetal programming of cognition.

Prenatal stress and the developing brain: Risks for neurodevelopmental disorders

The prenatal period is increasingly considered as a crucial target for the primary prevention of neurodevelopmental and psychiatric disorders. Understanding their pathophysiological mechanisms remains a great challenge. Our review reveals new insights from prenatal brain development research, involving (epi)genetic research, neuroscience, recent imaging techniques, physical modeling, and computational simulation studies. Studies examining the effect of prenatal exposure to maternal distress on offspring brain development, using brain imaging techniques, reveal effects at birth and up into adulthood. Structural and functional changes are observed in several brain regions including the prefrontal, parietal, and temporal lobes, as well as the cerebellum, hippocampus, and amygdala. Furthermore, alterations are seen in functional connectivity of amygdalar-thalamus networks and in intrinsic brain networks, including default mode and attentional networks. The observed changes underlie offspring behavioral, cognitive, emotional development, and susceptibility to neurodevelopmental and psychiatric disorders. It is concluded that used brain measures have not yet been validated with regard to sensitivity, specificity, accuracy, or robustness in predicting neurodevelopmental and psychiatric disorders. Therefore, more prospective long-term longitudinal follow-up studies starting early in pregnancy should be carried out, in order to examine brain developmental measures as mediators in mediating the link between prenatal stress and offspring behavioral, cognitive, and emotional problems and susceptibility for disorders.

Developmental origins of depression-related white matter properties: Findings from a prenatal birth cohort

Depression is the leading cause of years lost due to disability worldwide. Still, the mechanisms underlying its development are not well understood. This study aimed to evaluate white-matter properties associated with depressive symptomatology in young adulthood and their developmental origins. Diffusion tensor imaging and assessment of depressive symptomatology were conducted in 128 young adults (47% male, age 23-24) from a prenatal birth cohort (European Longitudinal Study of Pregnancy and Childhood). For a subset of these individuals, the database included information on prenatal stress (n = 93) and depressive symptoms during adolescence (assessed repeatedly at age 15 and 19). Depressive symptoms in young adulthood were associated with lower fractional anisotropy in the left and right cingulum and higher fractional anisotropy in the right corticospinal tract and superior longitudinal fasciculus. Further analyses revealed that prenatal stress and depressive symptomatology during adolescence were independent predictors of altered white-matter properties in the cingulum in young adulthood. We conclude that typically developing young adults with more depressive symptoms already exhibit tract-specific alterations in white-matter properties and that prenatal stress and depressive symptomatology during adolescence might contribute to their development.

Gene expression in cord blood links genetic risk for neurodevelopmental disorders with maternal psychological distress and adverse childhood outcomes

Prenatal exposure to maternal stress and depression has been identified as a risk factor for adverse behavioral and neurodevelopmental outcomes in early childhood. However, the molecular mechanisms through which maternal psychopathology shapes offspring development remain poorly understood. We applied transcriptome-wide screens to 149 umbilical cord blood samples from neonates born to mothers with posttraumatic stress disorder (PTSD; n = 20), depression (n = 31) and PTSD with comorbid depression (n = 13), compared to carefully matched trauma exposed controls (n = 23) and healthy mothers (n = 62). Analyses by maternal diagnoses revealed a clear pattern of gene expression signatures distinguishing neonates born to mothers with a history of psychopathology from those without. Co-expression network analysis identified distinct gene expression perturbations across maternal diagnoses, including two depression-related modules implicated in axon-guidance and mRNA stability, as well as two PTSD-related modules implicated in TNF signaling and cellular response to stress. Notably, these disease-related modules were enriched with brain-expressed genes and genetic risk loci for autism spectrum disorder and schizophrenia, which may imply a causal role for impaired developmental outcomes. These molecular alterations preceded changes in clinical measures at twenty-four months, including reductions in cognitive and socio-emotional outcomes in affected infants. Collectively, these findings indicate that prenatal exposure to maternal psychological distress induces neuronal, immunological and behavioral abnormalities in affected offspring and support the search for early biomarkers of exposures to adverse in utero environments and the classification of children at risk for impaired development.

A Meta-Analysis of Maternal Prenatal Depression and Anxiety on Child Socioemotional Development

OBJECTIVE

Observed associations between maternal prenatal stress and children's socioemotional development have varied widely in the literature. The objective of the current study was to provide a synthesis of studies examining maternal prenatal anxiety and depression and the socioemotional development of their children.

METHOD

Eligible studies through to February 2018 were identified using a comprehensive search strategy. Included studies examined the association between maternal prenatal depression or anxiety and the future development of their children's socioemotional development (eg, difficult temperament, behavioral dysregulation) up to 18 years later. Two independent coders extracted all relevant data. Random-effects meta-analyses were used to derive mean effect sizes and test for potential moderators.

RESULTS

A total of 71 studies met full inclusion criteria for data analysis. The weighted average effect size for the association between prenatal stress and child socioemotional problems was as follows: odds ratio (OR) = 1.66 (95% CI = 1.54-1.79). Effect sizes were stronger for depression (OR = 1.79; 95% CI = 1.61-1.99) compared to anxiety (OR = 1.50; 95% CI = 1.36-1.64). Moderator analyses indicated that effect sizes were stronger when depression was more severe and when socio-demographic risk was heightened.

CONCLUSION

Findings suggest that maternal prenatal stress is associated with offspring socioemotional development, with the effect size for prenatal depression being more robust than for anxiety. Mitigating stress and mental health difficulties in mothers during pregnancy may be an effective strategy for reducing offspring behavioral difficulties, especially in groups with social disadvantage and greater severity of mental health difficulties.

An experimental test of the fetal programming hypothesis: Can we reduce child ontogenetic vulnerability to psychopathology by decreasing maternal depression?

Maternal depression is one of the most common prenatal complications, and prenatal maternal depression predicts many child psychopathologies. Here, we apply the fetal programming hypothesis as an organizational framework to address the possibility that fetal exposure to maternal depressive symptoms during pregnancy affects fetal development of vulnerabilities and risk mechanisms, which enhance risk for subsequent psychopathology. We consider four candidate pathways through which maternal prenatal depression may affect the propensity of offspring to develop later psychopathology across the life span: brain development, physiological stress regulation (hypothalamic-pituitary-adrenocortical axis), negative emotionality, and cognitive (effortful) control. The majority of past research has been correlational, so potential causal conclusions have been limited. We describe an ongoing experimental test of the fetal programming influence of prenatal maternal depressive symptoms using a randomized controlled trial design. In this randomized controlled trial, interpersonal psychotherapy is compared to enhanced usual care among distressed pregnant women to evaluate whether reducing prenatal maternal depressive symptoms has a salutary impact on child ontogenetic vulnerabilities and thereby reduces offspring's risk for emergence of later psychopathology.

Maternal depressive symptoms during and after pregnancy and child developmental milestones

BACKGROUND

Maternal depressive symptoms during and after pregnancy predict poorer child neurodevelopment. The effects of timing, symptom severity, and additive influences remain unclear.

METHODS

A total of 2,231 mothers of the Prediction and Prevention of Pre-eclampsia and Intrauterine Growth Restriction (PREDO) study completed the Center for Epidemiological Studies Depression Scale biweekly up to 14 times during pregnancy and twice up to 12 months after pregnancy. At child's age 1.9-5.7 years, the mothers completed the Beck Depression Inventory-II on their concurrent depressive symptoms and Ages and Stages Questionnaire on child developmental milestones.

RESULTS

Higher mean maternal depressive symptoms, each biweekly score, and consistently clinically relevant symptomatology during pregnancy predicted lower total developmental milestones, fine and gross motor, communication, problem solving, and personal/social skills scores in children. Although maternal depressive symptoms up to 12 months after pregnancy and in early childhood also predicted lower developmental milestones scores, developmental milestones scores were the lowest in children whose mothers' depressive symptoms were above the clinical cutoff either only during pregnancy, both during and up to 12 months after pregnancy, or at each three time-points.

CONCLUSION

Maternal depressive symptoms during pregnancy, in the first year postpartum and in early childhood are associated with poorer child neurodevelopment. Our findings further suggest that antenatal and postpregnancy depression have additive effects on neurodevelopment. Children of mothers with the most chronic and severe depressive symptoms during pregnancy had the most neurodevelopmental disadvantages. Our findings emphasize the adverse effects of maternal depression during and after pregnancy and in early childhood on child neurodevelopment.

Prenatal Maternal Cortisol Has Sex-Specific Associations with Child Brain Network Properties

Elevated maternal cortisol concentrations have the potential to alter fetal development in a sex-specific manner. Female brains are known to show adaptive behavioral and anatomical flexibility in response to early-life exposure to cortisol, but it is not known how these sex-specific effects manifest at the whole-brain structural networks. A prospective longitudinal study of 49 mother child dyads was conducted with serial assessments of maternal cortisol levels from 15 to 37 gestational weeks. We modeled the structural network of typically developing children (aged 6-9 years) and examined its global connectome properties, rich-club organization, and modular architecture. Network segregation was susceptible only for girls to variations in exposure to maternal cortisol during pregnancy. Girls generated more connections than boys to maintain topologically capable and efficient neural circuits, and this increase in neural cost was associated with higher levels of internalizing problems. Maternal cortisol concentrations at 31 gestational weeks gestation were most strongly associated with altered neural connectivity in girls, suggesting a sensitive period for the maternal cortisol-offspring brain associations. Our data suggest that girls exhibit an adaptive response by increasing the neural network connectivity necessary for maintaining homeostasis and efficient brain function across the lifespan.

Prenatal exposure to maternal and paternal depressive symptoms and white matter microstructure in children

BACKGROUND

Prenatal maternal depression has been associated with multiple problems in offspring involving affect, cognition, and neuroendocrine functioning. This suggests that prenatal depression influences neurodevelopment. However, the underlying neurodevelopmental mechanism remains unclear. We prospectively assessed whether maternal depressive symptoms during pregnancy and at the child's age 3 years are related to white matter microstructure in 690 children. The association of paternal depressive symptoms with childhood white matter microstructure was assessed to evaluate genetic or familial confounding.

METHODS

Parental depressive symptoms were measured using the Brief Symptom Inventory. In children aged 6-9 years, we used diffusion tensor imaging to assess white matter microstructure characteristics including fractional anisotropy (FA) and mean diffusivity (MD).

RESULTS

Exposure to maternal depressive symptoms during pregnancy was associated with higher MD in the uncinate fasciculus and to lower FA and higher MD in the cingulum bundle. No associations of maternal depressive symptoms at the child's age of 3 years with white matter characteristics were observed. Paternal depressive symptoms also showed a trend toward significance for a lower FA in the cingulum bundle.

CONCLUSIONS

Prenatal maternal depressive symptoms were associated with higher MD in the uncinate fasciculus and the cingulum bundle. These structures are part of the limbic system, which is involved in motivation, emotion, learning, and memory. As paternal depressive symptoms were also related to lower FA in the cingulum, the observed effect may partly reflect a genetic predisposition and shared environmental family factors and to a lesser extent a specific intrauterine effect.

Perinatal maternal depressive symptoms alter amygdala functional connectivity in girls

Perinatal maternal depressive symptoms influence brain development of offspring. Such effects are particularly notable in the amygdala, a key structure involved in emotional processes. This study investigated whether the functional organization of the amygdala varies as a function of pre- and postnatal maternal depressive symptoms. The amygdala functional network was assessed using resting-state functional magnetic resonance imaging (rs-fMRI) in 128 children at age of 4.4 to 4.8 years. Maternal depressive symptoms were obtained at 26 weeks of gestation, 3 months, 1, 2, 3, and 4.5 years after delivery. Linear regression was used to examine associations between maternal depressive symptoms and the amygdala functional network. Prenatal maternal depressive symptoms were significantly associated with the functional connectivity between the amygdala and the cortico-striatal circuitry, especially the orbitofrontal cortex (OFC), insula, subgenual anterior cingulate (ACC), temporal pole, and striatum. Interestingly, greater pre- than post-natal depressive symptoms were associated with lower functional connectivity of the left amygdala with the bilateral subgenual ACC and left caudate and with lower functional connectivity of the right amygdala with the left OFC, insula, and temporal pole. These findings were only observed in girls but not in boys. Early exposure to maternal depressive symptoms influenced the functional organization of the cortico-striato-amygdala circuitry, which is intrinsic to emotional perception and regulation in girls. This suggests its roles in the transgenerational transmission of vulnerability for socio-emotional problems and depression. Moreover, this study underscored the importance of gender-dependent developmental pathways in defining the neural circuitry that underlies the risk for depression.

Trained innate immunity: a salient factor in the pathogenesis of neuroimmune psychiatric disorders

Historically, only cells of the adaptive immune system have been considered capable of retaining memory for infectious challenges. Recently, however, cells of the innate immune system have been shown to be capable of displaying long-term functional memory following a single immunostimulatory challenge, leading to enhanced production of proinflammatory molecules upon other subsequent, and temporally distant, immunostimulatory challenges. This effect has been termed 'trained innate immunity', and is underwritten by stable epigenetic changes in immune and metabolic pathways. Importantly, the long-term training of innate immune cells can occur as a result of infectious as well as and non-infectious challenges, including stress. Given the role that both stress and an activated immune system have in neuropathology, innate immune training has important implications for our understanding and treatment of neuropsychiatric disorders. This review focuses on the evidence for trained innate immunity and highlights some insights into its relevance for psychiatric diseases.

Maternal depressive symptoms during pregnancy are associated with amygdala hyperresponsivity in children

Depression during pregnancy is highly prevalent and has a multitude of potential risks of the offspring. Among confirmed consequences is a higher risk of psychopathology. However, it is unknown how maternal depression may impact the child's brain to mediate this vulnerability. Here we studied amygdala functioning, using task-based functional MRI, in children aged 6-9 years as a function of prenatal maternal depressive symptoms selected from a prospective population-based sample (The Generation R Study). We show that children exposed to clinically relevant maternal depressive symptoms during pregnancy (N = 19) have increased amygdala responses to negative emotional faces compared to control children (N = 20) [F(1,36) 7.02, p = 0.022]. Strikingly, postnatal maternal depressive symptoms, obtained at 3 years after birth, did not explain this relation. Our findings are in line with a model in which prenatal depressive symptoms of the mother are associated with amygdala hyperresponsivity in her offspring, which may represent a risk factor for later-life psychopathology.

Pre-pregnancy maternal depressive symptoms and low birth weight and preterm birth outcomes: Assessment of adolescent background characteristics and birth outcomes in adulthood

PURPOSE

In the United States and other countries of the world , high prevalence of pre-pregnancy depressive symptoms and depression during pregnancy is an important public health concern, as they are associated with low birth weight (LBW) and preterm birth (PTB) outcomes in adulthood. However, the relationships among pre-pregnancy depressive symptoms, low birth weight, preterm birth outcomes and household characteristics have not been well established.

METHODS

The study used data from 7120 adolescent female participants in the National Longitudinal Study of Adolescent to Adult Health data from Waves I (1994-1995 in-school interview), II (1996 as in-home), III (2001-2002 as in-home interview), IV (2008 as in-home interview) and Wave V is currently underway. The main outcomes were LBW and PTB. Maternal depressive symptoms were assessed with the Center for Epidemiologic Studies Depression scale (CES-D) using a cut-off point of 24 to indicate higher depressive symptoms . Odds ratios were used as an estimate of the relative risk using generalized estimating equations (GEE).

RESULTS

In Wave I, prevalence of depressive symptoms among age groups 11-15 (54.1%) was higher than older adolescents (45.9%) were. With the exception of depressive symptoms reported in Wave II, respondents reporting depressive symptoms in Waves I and III had similar unadjusted rates of LBW or PTB infants in adulthood. Mothers reporting higher depressive symptoms in older adolescence (15-19 years) had elevated odds of LBW infants (3.58 [95% CI=1.81, 7.09]) in Wave III compared with others reporting low depressive symptoms.

CONCLUSIONS

Undeniably, childhood socioeconomic circumstances are important determinants of disease risks and improved health functioning and in particular birth outcomes in adulthood. Since poorer households have fewer resources to cope with stressful events that generate mood and other depressive symptoms over the life course, findings of research suggest treating depressive symptoms prior to pregnancy will yield significant dividends for mothers and society. Furthermore, without careful control of household contexts, the association between depressive symptoms and birth outcomes is likely to be confounded.

Diffusion MRI of white matter microstructure development in childhood and adolescence: Methods, challenges and progress

Diffusion magnetic resonance imaging (dMRI) continues to grow in popularity as a useful neuroimaging method to study brain development, and longitudinal studies that track the same individuals over time are emerging. Over the last decade, seminal work using dMRI has provided new insights into the development of brain white matter (WM) microstructure, connections and networks throughout childhood and adolescence. This review provides an introduction to dMRI, both diffusion tensor imaging (DTI) and other dMRI models, as well as common acquisition and analysis approaches. We highlight the difficulties associated with ascribing these imaging measurements and their changes over time to specific underlying cellular and molecular events. We also discuss selected methodological challenges that are of particular relevance for studies of development, including critical choices related to image acquisition, image analysis, quality control assessment, and the within-subject and longitudinal reliability of dMRI measurements. Next, we review the exciting progress in the characterization and understanding of brain development that has resulted from dMRI studies in childhood and adolescence, including brief overviews and discussions of studies focusing on sex and individual differences. Finally, we outline future directions that will be beneficial to the field.

Prenatal Depression and Infant Temperament: The Moderating Role of Placental Gene Expression

Prior research has demonstrated the link between maternal depression during pregnancy (i.e., prenatal depression) and increased neurodevelopmental dysregulation in offspring. However, little is known about the roles of key hypothalamic-pituitary axis regulatory genes in the placenta modulating this association. This study will examine whether placental gene expression levels of 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2), glucocorticoid receptor (NR3C1), and mineralocorticoid receptor (NR3C2) can help elucidate the underlying mechanisms linking prenatal depression to infant temperament, particularly in infants with high negativity and low emotion regulation. Stored placenta tissues (N = 153) were used to quantify messenger ribonucleic acid levels of HSD11B2, NR3C1, and NR3C2. Assessments of prenatal depression and infant temperament at 6 months of age were ascertained via maternal report. Results found that prenatal depression was associated with increased Negative Affectivity (p < .05) after controlling for postnatal depression and psychosocial characteristics. Furthermore, the association between prenatal depression and Negative Affectivity was moderated by gene expression levels of HSD11B2, NR3C1, and NR3C2 such that greater gene expression significantly lessened the association between prenatal depression and Negative Affectivity. Our findings suggest that individual differences in placental gene expression may be used as an early marker of susceptibility or resilience to prenatal adversity.

Prenatal Major Depressive Disorder, Placenta Glucocorticoid and Serotonergic Signaling, and Infant Cortisol Response

OBJECTIVES

Extending prior studies of prenatal adversity and depressive symptoms, we tested associations between maternal prenatal major depressive disorder (MDD) and infant cortisol regulation. Based on prior findings by our group, we also tested placenta glucocorticoid (HSD11B2 methylation) and serotonin (SLC6A4 gene expression) signaling as moderators of links between prenatal MDD and infant cortisol.

METHODS

Participants were 153 mother-infant pairs from a low-income, diverse sample (M [SD] age = 26 [6] years). Repeated structured diagnostic interviews were used to identify mothers with (a) prenatal MDD, (b) preconception-only MDD, and (c) controls. Placenta samples were assayed for HSD11B2 methylation and SLC6A4 gene expression. Infant salivary cortisol response to a neurobehavioral examination was assessed at 1 month.

RESULTS

Daughters of prenatal MDD mothers had 51% higher baseline (ratio = 1.51; 95% confidence interval [CI] = 1.01-2.27; p = .045) and 64% higher stress responsive cortisol (ratio = 1.64; 95% CI = 1.05-2.56; p = .03) than daughters of controls and 75% higher stress-responsive cortisol (ratio = 1.75; 95% CI = 1.04-2.94; p = .04) than daughters of preconception-only MDD mothers. HSD11B2 methylation moderated links between prenatal MDD and baseline cortisol (p = .02), with 1% methylation decreases associated with 9% increased baseline cortisol in infants of prenatal MDD mothers (ratio = 1.09; 95% CI = 1.01-1.16). SLC6A4 expression moderated links between prenatal MDD and cortisol response among boys alone (p = .007), with 10-fold increases in expression associated with threefold increases in stress-responsive cortisol (ratio = 2.87; 95% CI = 1.39-5.93) in sons of control mothers.

CONCLUSIONS

Results highlight specificity of associations between prenatal versus preconception MDD and cortisol regulation and the importance and complexity of placenta glucocorticoid and serotonergic pathways underlying the intergenerational transmission of risk from maternal adversity.

The Future of Preschool Prevention, Assessment, and Intervention

Preschoolers are in the most rapid period of brain development. Environment shapes the structure and function of the developing brain. Promoting brain health requires cultivation of healthy environments at home, school, and in the community. This improves the emotional-behavioral and physical health of all children, can prevent problems in children at risk, and can alter the trajectory of children already suffering. For clinicians, this starts with assessing and treating the entire family, equipping parents with the principles of parent management training, and incorporating wellness prescriptions for nutrition, physical activity, music, and mindfulness.

Early Childhood Mental Health: Starting Early with the Pregnant Mother

Perinatal mental health has important implications for maternal and child outcomes. Most women with psychiatric disorders during pregnancy go undiagnosed and untreated, despite widespread initiatives for early identification. Universal screening for psychiatric disorders, particularly depression and anxiety, has been implemented in obstetric and primary care settings. However, there is little evidence regarding the effectiveness on psychiatric symptom reduction or prevention of adverse outcomes in children. Recently, comprehensive screening and follow-up programs integrated within obstetric or primary care settings have shown promising results in improving maternal mental health outcomes. Further work is needed to determine best clinical and most cost-effective practices.

Prenatal Depression Risk Factors, Developmental Effects and Interventions: A Review

This narrative review based on a literature search in PubMed and PsycInfo on the two terms prenatal and antenatal depression includes empirical studies, reviews and meta-analyses that have been published during the last 5 years on risk factors, developmental effects and interventions for prenatal depression. Risk factor studies that met criteria feature demographic measures (lower socioeconomic status, less education, non-marital status, non-employment, less social support and health locus of control, unintended pregnancy, partner violence and history of child abuse) and physiological variables (cortisol, amylase, and pro-inflammatory cytokines and intrauterine artery resistance). The negative effects include postpartum depression, paternal depression, and prematurity and low birth weight. Negative effects on infants include greater right frontal EEG, amygdala connectivity, cortical thinning and more difficult temperament. In childhood, externalizing and internalizing problems have been reported. The data on prenatal antidepressants (specifically SSRIs) reveal negative effects including internalizing problems as well as a greater risk for autism spectrum disorder. Prenatal interventions that have been effective include interpersonal psychotherapy, peer support, massage therapy, yoga, tai chi, and aerobic exercise. Potential underlying mechanisms are discussed as well as methodological limitations including homogeneity of samples and lack of randomization to intervention groups. Despite these limitations, the literature highlights the need for prenatal depression screening and intervention.

Maternal Depressive Symptoms During and After Pregnancy and Psychiatric Problems in Children

OBJECTIVE

Maternal depressive symptoms during pregnancy are associated with increased risk of psychiatric problems in children. A more precise understanding of the timing of the symptoms during pregnancy and their independence of other prenatal and postnatal factors in predicting child psychopathology risk is needed. We examined whether maternal depressive symptoms during pregnancy predict child psychiatric problems, whether these associations are trimester- or gestational-week-specific and/or independent of pregnancy disorders, and whether maternal depressive symptoms after pregnancy mediate or add to the prenatal effects.

METHOD

The study sample comprised 2,296 women and their children born in Finland between 2006-2010, participating in the prospective pregnancy cohort study Prediction and Prevention of Preeclampsia and Intrauterine Growth Restriction (PREDO) and followed up from 1.9 to 5.9 years of age. The women completed the Center for Epidemiologic Studies Depression Scale biweekly between gestational weeks+days 12+0/13+6 and 38+0/39+6 or delivery. In the follow-up, they completed the Beck Depression Inventory-II and Child Behavior Checklist 1½-5.

RESULTS

Maternal depressive symptoms during pregnancy predicted significantly higher internalizing (0.28 SD unit per SD unit increase [95% CI = 0.24-0.32]), externalizing (0.26 [0.23-0.30]), and total problems (0.31 [0.27-0.35]) in children. These associations were nonspecific to gestational week and hence pregnancy trimester, independent of pregnancy disorders, and independent of, although partially mediated by, maternal depressive symptoms after pregnancy. Psychiatric problems were greatest in children whose mothers reported clinically significant depressive symptoms across pregnancy trimesters and during and after pregnancy.

CONCLUSION

Maternal depressive symptoms during pregnancy predict increased psychiatric problems in young children. Preventive interventions from early pregnancy onward may benefit offspring mental health.

Does prenatal stress alter the developing connectome?

Human neurodevelopment requires the organization of neural elements into complex structural and functional networks called the connectome. Emerging data suggest that prenatal exposure to maternal stress plays a role in the wiring, or miswiring, of the developing connectome. Stress-related symptoms are common in women during pregnancy and are risk factors for neurobehavioral disorders ranging from autism spectrum disorder, attention deficit hyperactivity disorder, and addiction, to major depression and schizophrenia. This review focuses on structural and functional connectivity imaging to assess the impact of changes in women's stress-based physiology on the dynamic development of the human connectome in the fetal brain.

Prepartum and Postpartum Maternal Depressive Symptoms Are Related to Children's Brain Structure in Preschool

BACKGROUND

Perinatal maternal depression is a serious health concern with potential lasting negative consequences for children. Prenatal depression is associated with altered brain gray matter in children, though relations between postpartum depression and children's brains and the role of white matter are unclear.

METHODS

We studied 52 women who provided Edinburgh Postnatal Depression Scale (EPDS) scores during each trimester of pregnancy and at 3 months postpartum and their children who underwent magnetic resonance imaging at age 2.6 to 5.1 years. Associations between maternal depressive symptoms and magnetic resonance imaging measures of cortical thickness and white matter structure in the children were investigated.

RESULTS

Women's second trimester EPDS scores negatively correlated with children's cortical thickness in right inferior frontal and middle temporal regions and with radial and mean diffusivity in white matter emanating from the inferior frontal area. Cortical thickness, but not diffusivity, correlations survived correction for postpartum EPDS. Postpartum EPDS scores negatively correlated with children's right superior frontal cortical thickness and with diffusivity in white matter originating from that region, even after correcting for prenatal EPDS.

CONCLUSIONS

Higher maternal depressive symptoms prenatally and postpartum are associated with altered gray matter structure in children; the observed white matter correlations appear to be uniquely related to the postpartum period. The reduced thickness and diffusivity suggest premature brain development in children exposed to higher maternal perinatal depressive symptoms. These results highlight the importance of ensuring optimal women's mental health throughout the perinatal period, because maternal depressive symptoms appear to increase children's vulnerability to nonoptimal brain development.

Alterations in amygdala-prefrontal circuits in infants exposed to prenatal maternal depression

Prenatal exposure to maternal depression is common and puts offspring at risk for developing a range of neuropsychiatric disorders. Despite its prevalence and adverse associations, neurobiological processes by which prenatal maternal depression (PMD) confers risk remain poorly understood. Maternal mood and fetal behavior were assessed between 34 and 37 gestational weeks. Using resting-state functional magnetic resonance imaging (fMRI) and diffusion MRI, we examined functional and structural connectivity within amygdala-prefrontal circuits in 64 infants (mean age=5.8±1.7 weeks) with (n=20) and without (n=44) in utero exposure to PMD. Resting fMRI and diffusion MRI both indicated atypical amygdala-prefrontal connectivity in PMD-exposed infants: Resting fMRI indicated increased inverse, or negative, functional connectivity between the amygdala and the dorsal prefrontal cortex (PFC), bilaterally, and diffusion MRI indicated decreased structural connectivity between the right amygdala and the right ventral PFC. Spectral dynamic causal modeling supported these findings suggesting altered amygdala-PFC effective (or directed) connectivity in PMD-exposed infants. Last, path analyses supported a mechanistic account relating PMD to a third-trimester fetal behavior: PMD alters amygdala-PFC connectivity, which in turn, is associated with an increase in fetal heart rate reactivity to in utero perturbation. These data suggest that the maturation and coordination of central and peripheral physiology are altered by prenatal exposure to maternal depression. To the best of our knowledge, this is the first study to directly associate infant MRI measures with a behavior-fetal heart rate response, and supports hypotheses that PMD-associated variations in the development of amygdala-PFC circuits are relevant for future neurobehavioral maturation.

Prenatal maternal depression is associated with offspring inflammation at 25 years: a prospective longitudinal cohort study

Animal studies and a handful of prospective human studies have demonstrated that young offspring exposed to maternal prenatal stress show abnormalities in immune parameters and hypothalamic-pituitary-adrenal (HPA) axis function. No study has examined the effect of maternal prenatal depression on offspring inflammation and HPA axis activity in adulthood, nor the putative role of child maltreatment in inducing these abnormalities. High-sensitivity C-reactive protein (hs-CRP) and awakening cortisol were measured at age 25 in 103 young-adult offspring of the South London Child Development Study (SLCDS), a prospective longitudinal birth cohort of mother-offspring dyads recruited in pregnancy in 1986. Maternal prenatal depression was assessed in pregnancy at 20 and 36 weeks; offspring child maltreatment (birth 17 years) was assessed at offspring ages 11, 16 and 25; and offspring adulthood depression (18-25 years) was assessed at age 25. Exposure to maternal prenatal depression predicted significantly elevated offspring hs-CRP at age 25 (odds ratio=11.8, 95% confidence interval (CI) (1.1, 127.0), P=0.041), independently of child maltreatment and adulthood depression, known risk factors for adulthood inflammation. In contrast, maternal prenatal depression did not predict changes in offspring adulthood cortisol; however, offspring exposure to child maltreatment did, and was associated with elevated awakening cortisol levels (B=161.9, 95% CI (45.4, 278.4), P=0.007). Fetal exposure to maternal depression during pregnancy has effects on immune function that persist for up to a quarter of a century after birth. Findings are consistent with the developmental origins of health and disease (DOHaD) hypothesis for the biological embedding of gestational psychosocial adversity into vulnerability for future physical and mental illness.

Antenatal depression, treatment with selective serotonin reuptake inhibitors, and neonatal brain structure: A propensity-matched cohort study

The aim of this propensity-matched cohort study was to evaluate the impact of prenatal SSRI exposure and a history of maternal depression on neonatal brain volumes and white matter microstructure. SSRI-exposed neonates (n=27) were matched to children of mothers with no history of depression or SSRI use (n=54). Additionally, neonates of mothers with a history of depression, but no prenatal SSRI exposure (n=41), were matched to children of mothers with no history of depression or SSRI use (n=82). Structural magnetic resonance imaging and diffusion weighted imaging scans were acquired with a 3T Siemens Allegra scanner. Global tissue volumes were characterized using an automatic, atlas-moderated expectation maximization segmentation tool. Local differences in gray matter volumes were examined using deformation-based morphometry. Quantitative tractography was performed using an adaptation of the UNC-Utah NA-MIC DTI framework. SSRI-exposed neonates exhibited widespread changes in white matter microstructure compared to matched controls. Children exposed to a history of maternal depression but no SSRIs showed no significant differences in brain development compared to matched controls. No significant differences were found in global or regional tissue volumes. Additional research is needed to clarify whether SSRIs directly alter white matter development or whether this relationship is mediated by depressive symptoms during pregnancy.

Prenatal maternal depression and child serotonin transporter linked polymorphic region (5-HTTLPR) and dopamine receptor D4 (DRD4) genotype predict negative emotionality from 3 to 36 months

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.

PRENATAL EXPOSURE TO MATERNAL AND PATERNAL DEPRESSIVE SYMPTOMS AND BRAIN MORPHOLOGY: A POPULATION-BASED PROSPECTIVE NEUROIMAGING STUDY IN YOUNG CHILDREN

BACKGROUND

Prenatal depressive symptoms have been associated with multiple adverse outcomes. Previously, we demonstrated that prenatal depressive symptoms were associated with impaired growth of the fetus and increased behavioral problems in children aged between 1.5 and 6 years. In this prospective study, we aimed to assess whether prenatal maternal depressive symptoms at 3 years have long-term consequences on brain development in a cohort of children aged 6-10 years. As a contrast, the association of paternal depressive symptoms during pregnancy and brain morphology was assessed to serve as a marker of background confounding due to shared genetic and environmental family factors.

METHODS

We assessed parental depressive symptoms during pregnancy with the Brief Symptom Inventory. At approximately 8 years of age, we collected structural neuroimaging data, using cortical thickness, surface area, and gyrification as outcomes (n = 654).

RESULTS

We found that exposure to prenatal maternal depressive symptoms during pregnancy was associated with a thinner superior frontal cortex in the left hemisphere. Additionally, prenatal maternal depressive symptoms were related to larger caudal middle frontal area in the left hemisphere. Maternal depressive symptoms at 3 years were not associated with cortical thickness, surface area, or gyrification in the left and right hemispheres. No effects of paternal depressive symptoms on brain morphology were observed.

CONCLUSIONS

Prenatal maternal depressive symptoms were associated with differences in brain morphology in children. It is important to prevent, identify, and treat depressive symptoms during pregnancy as it may have long-term consequences on child brain development.

Fetal exposure to placental corticotropin-releasing hormone is associated with child self-reported internalizing symptoms

OBJECTIVE

Fetal exposure to maternal prenatal stress hormones such as cortisol exerts influences on the developing nervous system that persist and include risk for internalizing symptoms later in life. Placental corticotropin-releasing hormone (pCRH) is a feto-placental stress signal that also shapes fetal neurodevelopment and may be a more direct indicator of the fetal experience than maternal stress hormones. The programming effects of pCRH on child development are unknown. The current investigation examined associations between prenatal maternal and placental stress hormone exposures (maternal cortisol and pCRH) and child self-reported internalizing symptoms at age 5.

METHOD

Maternal plasma cortisol and pCRH levels were measured at 15, 19, 25, 31, and 36 weeks' gestation in a sample of 83 women and their 91 children (8 sibling pairs from separate pregnancies), who were born full-term. Child self-reported internalizing symptoms at age 5 were obtained using scales of the Berkeley Puppet Interview.

RESULTS

Placental CRH profiles (including elevations in mid-gestation) were associated with higher levels of internalizing symptoms at age 5. This effect was not explained by critical prenatal or postnatal influences, including obstetric risk, concurrent maternal psychological state, and family socio-economic status. Prenatal maternal cortisol was not significantly associated with child self-reported internalizing symptoms.

CONCLUSIONS

Findings suggest that elevated exposures to the feto-placental stress signal pCRH exert programming effects on the developing fetal central nervous system, with lasting consequences for child mental health.

Serotonin signaling modulates the effects of familial risk for depression on cortical thickness

Depression is a highly familial and a heritable illness that is more prevalent in the biological offspring of the depressed individuals than in the general population. In a 3-generation, 30-year, longitudinal study of individuals at either a high(HR) or a low(LR) familial risk for depression, we previously showed cortical thinning in the right hemisphere was an endophenotype for the familial risk. In this study, we assessed whether the effects of familial risk were modulated by the serotonin-transporter-linked polymorphic region (5-HTTLPR). We measured cortical thickness using MRI of the brain and associated it with 5-HTTLPR polymorphism in 76 HR and 53 LR individuals. We studied the effects of genotype and gene-by-risk interaction on cortical thickness while controlling for the confounding effects of age and gender, and for the familial relatedness by applying a variance component model with random effects for genotype. The results showed significant effects of gene-by-risk interaction on thickness: The "s" allele was associated with thinner cortex in the LR individuals whereas with thicker cortex in the HR individuals. The opposing gene effects across the two risk groups were likely due to either epistatic effects and/or differing modulation of the neural plasticity by the altered 5-HT signaling in utero.

MYSTERIES OF THE HUMAN FETUS REVEALED

The impressive program of research from the DiPietro laboratory succeeds in its aim to document the ontogeny of human fetal neurobehavioral development. From studies of great depth and breadth, and wielding creative methods of assessment, DiPietro et al. open a window into the largely inaccessible developing human fetal brain. This commentary, with reference to the seminal cardiovascular studies of the Laceys, supports the measures of the fetal heart to index fetal well-being and to provide evidence of stimulus processing. A separate case is made that the DiPietro program provides unique and invaluable information for assessing the influential Developmental Origins of Health and Disease or Fetal Programming Models. The goal of these models, to predict or understand the influences of early experience or response patterns on later postnatal life, is identical to the ultimate goal of the DiPietro program. Because human fetal behavior is uncontaminated by socialization or parenting or peers, it may be the best reflection of fetal exposures. The remarkable neurobehavioral profiles generated by the DiPietro program can make a critical contribution to the Fetal Programming Model in terms of sensitive and critical periods of nervous system vulnerability and to specify gestational periods of neurobehavioral risk.

Imaging the "At-Risk" Brain: Future Directions

OBJECTIVES

Clinical neuroscience is increasingly turning to imaging the human brain for answers to a range of questions and challenges. To date, the majority of studies have focused on the neural basis of current psychiatric symptoms, which can facilitate the identification of neurobiological markers for diagnosis. However, the increasing availability and feasibility of using imaging modalities, such as diffusion imaging and resting-state fMRI, enable longitudinal mapping of brain development. This shift in the field is opening the possibility of identifying predictive markers of risk or prognosis, and also represents a critical missing element for efforts to promote personalized or individualized medicine in psychiatry (i.e., stratified psychiatry).

METHODS

The present work provides a selective review of potentially high-yield populations for longitudinal examination with MRI, based upon our understanding of risk from epidemiologic studies and initial MRI findings.

RESULTS

Our discussion is organized into three topic areas: (1) practical considerations for establishing temporal precedence in psychiatric research; (2) readiness of the field for conducting longitudinal MRI, particularly for neurodevelopmental questions; and (3) illustrations of high-yield populations and time windows for examination that can be used to rapidly generate meaningful and useful data. Particular emphasis is placed on the implementation of time-appropriate, developmentally informed longitudinal designs, capable of facilitating the identification of biomarkers predictive of risk and prognosis.

CONCLUSIONS

Strategic longitudinal examination of the brain at-risk has the potential to bring the concepts of early intervention and prevention to psychiatry.

Prenatal stress, development, health and disease risk: A psychobiological perspective-2015 Curt Richter Award Paper

The long-term consequences of exposure to excess stress, particularly during sensitive developmental windows, on the initiation and progression of many complex, common physical and mental disorders that confer a major global burden of disease are well established. The period of intrauterine life represents among the most sensitive of these windows, at which time the effects of stress may be transmitted inter-generationally from a mother to her as-yet-unborn child. As explicated by the concept of fetal or developmental programming of health and disease susceptibility, a growing body of evidence supports the notion that health and disease susceptibility is determined by the dynamic interplay between genetic makeup and environment, particularly during intrauterine and early postnatal life. Except in extreme cases, an adverse intrauterine exposure may not, per se, 'cause' disease, but, instead, may determine propensity for disease(s) in later life (by shaping phenotypic responsivity to endogenous and exogenous disease-related risk conditions). Accumulating evidence suggests that maternal psychological and social stress during pregnancy represents one such condition that may adversely affect the developing child, with important implications for a diverse range of physical and mental health outcomes. In this paper we review primarily our own contributions to the field of maternal stress during pregnancy and child mental and physical health-related outcomes. We present findings on stress-related maternal-placental-fetal endocrine and immune/inflammatory processes that may mediate the effects of various adverse conditions during pregnancy on the developing human embryo and fetus. We enunciate conceptual and methodological issues related to the assessment of stress during pregnancy and discuss potential mechanisms of intergenerational transmission of the effects of stress. Lastly, we describe on-going research and some future directions of our program.

Fetal exposure to placental corticotropin-releasing hormone (pCRH) programs developmental trajectories

The maternal endocrine stress system is profoundly altered during the course of human pregnancy. The human placenta expresses the genes for CRH as early as the seventh week of gestation and it is the expotential increase in placental CRH (pCRH) over the course of human gestation that is responsible for the greatest modification in the maternal stress system. The bi-directional placental release of hormones into the maternal and fetal compartments has profound influences for both. The influential Fetal Programming model predicted that early or fetal exposures to maternal signals of threat or adverse conditions have lifelong consequences for health outcomes. A basic assumption of this model was that developing organisms play a dynamic role in their own construction. Data are reviewed and new data are presented that elevated pCRH over the course of human gestation plays a fundamental role in the organization of the fetal nervous system, modifies birth phenotype (the timing of the onset of spontaneous labor and delivery), and influences developmental, temperamental and metabolic trajectories. Evidence for sex differences and conserved function across species is presented. Finally, a model is presented that proposes several pathways that pCRH can program risk for health and disease.