Amygdala Reward Reactivity Mediates the Association Between Preschool Stress Response and Depression Severity

Dimensions of Depressive Symptoms in Young Children: Factor Analysis of the Preschool Feelings Checklist-Scale

The current study is an investigation of the dimensionality of the Preschool Feelings Checklist-Scale (PFC-S), a caregiver-report questionnaire of early childhood depressive symptom severity. Caregivers of 450 young children, ages 3-8 years (M = 5.62, SD = 0.95; 49% female; 7% Hispanic; 66% White), completed the PFC-S and questionnaires on child emotion regulation and expression and self-reported depressive symptomatology. Confirmatory factor analyses indicated that a one-factor structure did not adequately fit the current PFC-S data. Using exploratory factor analysis, a three-factor structure emerged as interpretable and structurally sound, yielding reliable factors related to social and behavioral anhedonia, emotional and behavioral dysregulation, and excessive guilt and sadness. This factor structure showed configural and scalar invariance across preschool-aged and early middle childhood-aged children as well as children assigned male and female sex at birth. Correlations between the three factors and constructs related to depression suggested preliminary construct validity. The current study provides initial evidence for a multidimensional structure of the PFC-S and improves our understanding of early childhood depressive symptoms.

The Development of Stress Reactivity and Regulation in Children and Adolescents

Adversity experienced in early life can have detrimental effects on physical and mental health. One pathway in which these effects occur is through the hypothalamic-pituitary-adrenal (HPA) axis, a key physiological stress-mediating system. In this review, we discuss the theoretical perspectives that guide stress reactivity and regulation research, the anatomy and physiology of the axis, developmental changes in the axis and its regulation, brain systems regulating stress, the role of genetic and epigenetics variation in axis development, sensitive periods in stress system calibration, the social regulation of stress (i.e., social buffering), and emerging research areas in the study of stress physiology and development. Understanding the development of stress reactivity and regulation is crucial for uncovering how early adverse experiences influence mental and physical health.

In Context: A Developmental Model of Reward Processing, With Implications for Autism and Sensitive Periods

OBJECTIVE

Differences in reward processing have been associated with numerous psychiatric disorders, including autism and attention-deficit/hyperactivity disorder (ADHD). Many attempts to understand reward processing characterize differences in clinical populations after disorder onset; however, divergence may begin much earlier. In fact, the typical developmental progression of reward processing in infancy and early childhood is poorly understood. We re-conceptualize classic infant developmental constructs such as preferential looking into a Six-Component Developmental Model of Reward Processing: an infant- and young child-focused framework to guide research and assessment of reward processing across development.

METHOD

The extant developmental literature including recent textbooks, systematic reviews, and meta-analyses was reviewed to build a conceptual framework. We describe experimental paradigms to assess each developmental component of reward processing longitudinally from infancy. A timeline of each component's emergence was estimated.

RESULTS

Six components of reward processing were identified-association, discrimination, preference/valuation, effort, anticipation, and response. Selected evidence suggests emergence between birth and 6 months. Application of this model to autism led to a reinterpretation of existing disparate results, and illuminated a path to study the developmental processes underlying a popular hypothesis of autism, the motivation hypothesis. Current evidence further suggests that a sensitive period may exist for the emergence of reward processing.

CONCLUSION

The proposed framework offers a useful reconceptualization of the extant literature. Future longitudinal work using the suggested experimental paradigms with high-risk populations could elucidate the developmental trajectory of the components and timing of potential sensitive period(s) for each component.

Effect of Tai Chi on Young Adults with Subthreshold Depression via a Stress-Reward Complex: A Randomized Controlled Trial

BACKGROUND

Subthreshold depression is a highly prevalent mood disorder in young adults. Mind-body exercises, such as Tai Chi, have been adopted as interventions for clinical depressive symptoms. However, the possible effect and underlying mechanism of Tai Chi on subthreshold depression of young individuals remain unclear. This randomized controlled study aimed to evaluate the effects of Tai Chi training and tested the combined stress and reward circuitry model for subthreshold depression.

RESULTS

A total of 103 participants completed this trial, with 49 in the 12-week 24-style Tai Chi group and 54 participants in control group. Our results showed significantly lower scores on depressive symptoms (P = 0.002) and anxiety symptoms (P = 0.009) and higher scores on quality of life (P = 0.002) after Tai Chi training. There were significant reductions in salivary cortisol levels (P = 0.007) and putamen gray matter volume (P < 0.001) in the Tai Chi group. The changes in cortisol levels and putamen gray matter volume had direct (bootstrapping confidence interval [- 0.91, - 0.11]) and indirect effects (bootstrapping confidence interval [- 0.65, - 0.19]) on the changes induced by Tai Chi training on depressive symptoms, respectively.

CONCLUSION

The stress-reward complex results indicated an interaction between lowering stress levels and increasing reward circuitry activity associated with the alleviation of depressive symptoms among participants. The 12-week Tai Chi training was effective in improving the symptoms and quality of life of young adults with subthreshold depression. Trial Registration Chinese Registry of Clinical Trials (Registration Number: ChiCTR1900028289, Registered December 12, 2019).

Association between reward-related functional connectivity and tri-level mood and anxiety symptoms

Depression and anxiety are associated with abnormalities in brain regions that process rewards including the medial orbitofrontal cortex (mOFC), the ventral striatum (VS), and the amygdala. However, there are inconsistencies in these findings. This may be due to past reliance on categorical diagnoses that, while valuable, provide less precision than may be required to understand subtle neural changes associated with symptoms of depression and anxiety. In contrast, the tri-level model defines symptom dimensions that are common (General Distress) or relatively specific (Anhedonia-Apprehension, Fears) to depression and anxiety related disorders, which provide increased precision. In the current study, eligibility was assessed by quasi-orthogonal screening questionnaires measuring reward and threat sensitivity (Behavioral Activation Scale; Eysenck Personality Questionnaire-Neuroticism). These participants were assessed on tri-level symptom severity and completed the Monetary Incentive Delay task during fMRI scanning. VS-mOFC and VS-amygdala connectivity were estimated during reward anticipation and reward outcome. Heightened General Distress was associated with lower VS-mOFC connectivity during reward anticipation (b = -0.064, p = 0.021) and reward outcome (b = -0.102, p = 0.014). Heightened Anhedonia-Apprehension was associated with greater VS-amygdala connectivity during reward anticipation (b = 0.065, p = 0.004). The present work has important implications for understanding the coupling between the mOFC and vS and the amygdala and the vS during reward processing in the pathophysiology of mood and anxiety symptoms and for developing targeted behavioral, pharmacological, and neuromodulatory interventions to help manage these symptoms.

Cortical Development Mediates Association of Prenatal Maternal Depressive Symptoms and Child Reward Sensitivity: A Longitudinal Study

OBJECTIVE

Maternal depression during pregnancy has long-term impacts on offspring. This study used neuroimaging and behavioral data from children aged 4 to 6 years and investigated whether prenatal maternal depressive symptoms (pre-MDS) associated with child cortical morphological development and subsequent reward-related behaviors in preschoolers.

METHOD

Pre-MDS was measured using the Edinburgh Postnatal Depression Scale at 26 weeks of pregnancy. Children (n = 130) underwent structural magnetic resonance imaging (MRI) at both 4 and 6 years of age. Child sensitivity to reward and punishment was reported by mothers when children were 6 years of age. Linear mixed-effect models examined pre-MDS associations with child cortical thickness and surface area. Mediation analysis examined whether cortical development mediated associations between pre-MDS and child sensitivity to reward and punishment.

RESULTS

The 3-way interactions of pre-MDS, age, and sex on cortical thickness and surface area were not statistically significant. We found a significant interaction of pre-MDS with sex on the cortical surface area but not on thickness or their growth from 4 to 6 years, adjusting for ethnicity, socioeconomic status, baseline age, and postnatal MDS as covariates. Higher pre-MDS scores were associated with larger surface areas in the prefrontal cortex, superior temporal gyrus, and superior parietal lobe (SPL) in boys, whereas the opposite pattern was seen in girls. The SPL surface area mediated the relationship between pre-MDS and sensitivity to reward in girls.

CONCLUSION

Prenatal maternal depression alters the cortical morphology of pre-schoolers in a sex-dependent manner.

Kindergarten-Based Progressive Muscle Relaxation Training Enhances Attention and Executive Functioning in 5-6-year-old Children: A Randomized Controlled Trial

In the present study we assessed the impact of kindergarten-based progressive muscle relaxation (PMR) on attention and executive functioning of 5-6-year-old children. In this randomized-controlled trial, 52 children (26 female; 26 male; M age = 5.4, SD = 0.2 years) from two private Tunisian kindergartens were randomly assigned to experimental and control groups. Over 12 weeks, 18 children performed PMR in two 30-minute sessions/week, another 17 children performed generic physical education (PE) for two 30-minute sessions/week, and 17 children in a control group (CG) had no systematically guided physical activity and engaged in usual self-chosen activities like free play or artisanal activities during Kindergarten hours. Prior to (T0) and after (T1) the 12-week PMR intervention, all participants completed the Visuomotor Precision and Statue subtests of the Neuropsychological Evaluation Battery (NEPSY-2), the Teddy Bear Cancellation Test, and the Rey Simple Figure Test. While there were no significant group differences at T0, repeated measures analysis of variance revealed higher scores for the PMR group relative to both the PE and CG groups on measures of attention, visuomotor precision, memory, and motor inhibition. PMR provided an effective relaxation technique and enhanced attention and executive functioning of these 5-6-year-old children, with important implications for assisting learning and academic achievement among young children.

Translating RDoC to Real-World Impact in Developmental Psychopathology: A Neurodevelopmental Framework for Application of Mental Health Risk Calculators

The National Institute of Mental Health Research Domain Criteria's (RDoC) has prompted a paradigm shift from categorical psychiatric disorders to considering multiple levels of vulnerability for probabilistic risk of disorder. However, the lack of neurodevelopmentally-based tools for clinical decision-making has limited RDoC's real-world impact. Integration with developmental psychopathology principles and statistical methods actualize the clinical implementation of RDoC to inform neurodevelopmental risk. In this conceptual paper, we introduce the probabilistic mental health risk calculator as an innovation for such translation and lay out a research agenda for generating an RDoC- and developmentally-informed paradigm that could be applied to predict a range of developmental psychopathologies from early childhood to young adulthood. We discuss methods that weigh the incremental utility for prediction based on intensity and burden of assessment, the addition of developmental change patterns, considerations for assessing outcomes, and integrative data approaches. Throughout, we illustrate the risk calculator approach with different neurodevelopmental pathways and phenotypes. Finally, we discuss real-world implementation of these methods for improving early identification and prevention of developmental psychopathology. We propose that mental health risk calculators can build a needed bridge between RDoC's multiple units of analysis and developmental science.

Brain-Based Biotypes of Psychiatric Vulnerability in the Acute Aftermath of Trauma

OBJECTIVE

Major negative life events, such as trauma exposure, can play a key role in igniting or exacerbating psychopathology. However, few disorders are diagnosed with respect to precipitating events, and the role of these events in the unfolding of new psychopathology is not well understood. The authors conducted a multisite transdiagnostic longitudinal study of trauma exposure and related mental health outcomes to identify neurobiological predictors of risk, resilience, and different symptom presentations.

METHODS

A total of 146 participants (discovery cohort: N=69; internal replication cohort: N=77) were recruited from emergency departments within 72 hours of a trauma and followed for the next 6 months with a survey, MRI, and physiological assessments.

RESULTS

Task-based functional MRI 2 weeks after a motor vehicle collision identified four clusters of individuals based on profiles of neural activity reflecting threat reactivity, reward reactivity, and inhibitory engagement. Three clusters were replicated in an independent sample with a variety of trauma types. The clusters showed different longitudinal patterns of posttrauma symptoms.

CONCLUSIONS

These findings provide a novel characterization of heterogeneous stress responses shortly after trauma exposure, identifying potential neuroimaging-based biotypes of trauma resilience and psychopathology.

A Brief Early Childhood Screening Tool for Psychopathology Risk in Primary Care: The Moderating Role of Poverty

OBJECTIVES

To evaluate the Preschool Feeling Checklist (PFC) utility for predicting later mental disorders and functioning for children and assess whether the PFC's predictive utility differs as a function of childhood poverty.

STUDY DESIGN

We analyzed data from a prospective longitudinal study of preschoolers in St Louis. Preschoolers (N = 287) were recruited from primary care sites and were assessed annually for 10-15 years. The PFC screened for depressive symptoms. Later age-appropriate psychiatric diagnostic interviews were used to derive Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, diagnoses. Regression and moderation analyses, and multilevel modeling were used to test the association between the PFC and later outcomes, and whether this relationship was moderated by income-to-needs.

RESULTS

The PFC predicted major depressive disorder (OR 1.13, P < .001), attention deficit hyperactivity disorder (OR 1.16, P < .001), and mania (OR 1.18, P < .05) in adolescence and early adulthood. Income-to-needs was a moderator in the predictive pathway between the PFC and later major depressive disorder (OR 1.10, P < .05) and mania (OR 1.19, P < .001) with the measure less predictive for children living in poverty. The PFC predicted worse functioning by the final assessment (b = 1.71, SE = 0.51, P = .001).

CONCLUSIONS

The PFC served as an indicator of risk for later attention deficit hyperactivity disorder and impairment in all children. It has predictive utility for later mood disorders only in children living above the poverty line. Predicting depression in children living below the poverty line may require consideration of risk factors not covered by the PFC.

Stress-induced cortisol response is associated with right amygdala volume in early childhood

Rodent research suggests that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and the resulting cortisol stress response can alter the structure of the hippocampus and amygdala. Because early-life changes in brain structure can produce later functional impairment and potentially increase risk for psychiatric disorder, it is critical to understand the relationship between the cortisol stress response and brain structure in early childhood. However, no study to date has characterized the concurrent association between cortisol stress response and hippocampal and amygdala volume in young children. In the present study, 42 young children (M age  = 5.97, SD = 0.76), completed a frustration task and cortisol response to stress was measured. Children also underwent magnetic resonance imaging (MRI), providing structural scans from which their hippocampal and amygdala volumes were extracted. Greater cortisol stress response was associated with reduced right amygdala volume, controlling for whole brain volume, age, sex, and number of cortisol samples. There were no significant associations between cortisol stress response and bilateral hippocampus or left amygdala volumes. The association between right amygdala volume and cortisol stress response raises the non-mutually exclusive possibilities that the function of the HPA axis may shape amygdala structure and/or that amygdala structure may shape HPA axis function. As both cortisol stress response and amygdala volume have been associated with risk for psychopathology, it is possible that the relationship between cortisol stress response and amygdala volume is part of a broader pathway contributing to psychiatric risk.

[Anhedonia in depression: neurobiological and genetic aspects]

Anhedonia is indeed a pathogenetically important clinical phenotype and a promising endophenotype for depressive symptoms with a very high contribution of biological and genetic factors. Neurobiological mechanisms of anhedonia are impaired functioning of the reward system of the brain, which is confirmed by many neuroimaging, genetic and experimental studies. Anhedonia has a trans-diagnoctic character and should be understood as a complex phenomenon, and it is important to correctly evaluate it within the framework of a particular research paradigm. It seems optimal to form several complementary research strategies that evaluate the most important «facets» of anhedonia, regardless of the nosological form of the disease, within the framework of one study using various methods to search for adequate biomarkers of anhedonia severity (genetic, neuroimaging, biochemical). Given the high-quality organization of such comprehensive studies based on the correct methodology of evidence-based medicine, it is likely that significant biomarker systems will be available in the near future, which, if replicated in independent samples, can be used to personalize the diagnosis and treatment of depression.

Reliability and Validity of Preschool Feelings Checklist

The Preschool Feelings Checklist (PFC) is a 16-item parent report measure of depressive symptoms in young children. However, data on its reliability and validity are limited. We examined the internal consistency and convergent, discriminant, and predictive validity of the PFC in an unselected community sample of 490 3-year old children. Child psychopathology was assessed using semi-structured diagnostic interviews conducted with a parent at ages 3 and 6 (the Preschool Age Psychiatric Assessment) and with the child and a parent at ages 9, 12, and 15 (the Kiddie Schedule for the Affective Disorders and Schizophrenia, Present and Lifetime Version). The PFC exhibited good internal consistency. It was concurrently associated with depression, as well as a wide range of other psychiatric disorders and functional impairment. Similarly, the PFC at 3 years independently predicted depression and a range of other disorders and global functioning in subsequent assessments later in childhood and in adolescence. Finally, the PFC outperformed the longer Child Behavior Checklist in predicting diagnoses and functioning. Results support the concurrent and predictive validity of the PFC in preschoolers. However, it also exhibited concurrent and predictive associations with a number of other disorders, suggesting that it indexes a broad transdiagnostic liability for psychopathology and impairment.

The social ecology of childhood and early life adversity

An increasing prevalence of early childhood adversity has reached epidemic proportions, creating a public health crisis. Rather than focusing only on adverse childhood experiences (ACEs) as the main lens for understanding early childhood experiences, detailed assessments of a child's social ecology are required to assess "early life adversity." These should also include the role of positive experiences, social relationships, and resilience-promoting factors. Comprehensive assessments of a child's physical and social ecology not only require parent/caregiver surveys and clinical observations, but also include measurements of the child's physiology using biomarkers. We identify cortisol as a stress biomarker and posit that hair cortisol concentrations represent a summative and chronological record of children's exposure to adverse experiences and other contextual stressors. Future research should use a social-ecological approach to investigate the robust interactions among adverse conditions, protective factors, genetic and epigenetic influences, environmental exposures, and social policy, within the context of a child's developmental stages. These contribute to their physical health, psychiatric conditions, cognitive/executive, social, and psychological functions, lifestyle choices, and socioeconomic outcomes. Such studies must inform preventive measures, therapeutic interventions, advocacy efforts, social policy changes, and public awareness campaigns to address early life adversities and their enduring effects on human potential. IMPACT: Current research does not support the practice of using ACEs as the main lens for understanding early childhood experiences. The social ecology of early childhood provides a contextual framework for evaluating the long-term health consequences of early life adversity. Comprehensive assessments reinforced with physiological measures and/or selected biomarkers, such as hair cortisol concentrations to assess early life stress, may provide critical insights into the relationships between early adversity, stress axis regulation, and subsequent health outcomes.

Brain stimulation rewarding experience attenuates neonatal clomipramine-induced adulthood anxiety by reversal of pathological changes in the amygdala

Major depressive disorder (MDD) is associated with enhanced anxiety and reduced reward processing leading to impaired cognitive flexibility. These pathological changes during depression are accompanied by dysfunctional hypothalamic-pituitary-adrenal (HPA) axis and its impaired regulation by the amygdala. Notably, the electrical stimulation of brain reward areas produces an antidepressant effect in both MDD patients and animal models of depression. However, the effects of chronic electrical self-stimulation of lateral hypothalamus - medial forebrain bundle (LH-MFB) on depression-associated anxiety and accompanying changes in plasma corticosterone levels, structural, and neurochemical alterations in the amygdala are unknown. Here, we used the neonatal clomipramine (CLI) model of depression. During adulthood, neonatal CLI and vehicle administered rats were subjected to bilateral electrode implantation at LH-MFB and trained to receive intracranial self-stimulation (ICSS) for 14 days. Rats were then tested for anhedonic and anxiety-like behaviors, followed by estimation of plasma corticosterone levels, assessment of amygdalar volumes and neuronal/glial numbers, levels of monoamines and their metabolites in the amygdala. We found that chronic ICSS of LH-MFB reverses CLI-induced anhedonia and anxiety. Interestingly, amelioration of CLI-induced enhanced anhedonia and anxiety in ICSS rats was associated with partial reversal of enhanced plasma corticosterone levels, hypertrophy of basolateral amygdala (BLA), and altered noradrenaline (NA) metabolism in the amygdalar complex. We suggest that beneficial effects of ICSS on CLI-induced anxiety at least in part mediated by the restoration of amygdalar and HPA axis functioning. Our results support the hypothesis that brain stimulation rewarding experience might be evolved as a therapeutic strategy for reversal of amygdalar dysfunction in depression.

Neural Indicators of Anhedonia: Predictors and Mechanisms of Treatment Change in a Randomized Clinical Trial in Early Childhood Depression

BACKGROUND

Early childhood depression is associated with anhedonia and reduced event-related potential (ERP) responses to rewarding or pleasant stimuli. Whether these neural measures are indicators of target engagement or treatment outcome is not yet known.

METHODS

We measured ERP responses to win and loss feedback in a guessing task and to pleasant versus neutral pictures in young (4.0-6.9 years of age) depressed children before and after randomization to either 18 weeks of Parent-Child Interaction Therapy-Emotion Development (PCIT-ED) or waitlist.

RESULTS

Analyses included reward positivity (RewP) data from 118 children randomly assigned to PCIT-ED (n = 60) or waitlist (n = 58) at baseline and late positive potential (LPP) data from 99 children (44 assigned to PCIT-ED vs. 55 assigned to waitlist) at baseline. Children undergoing PCIT-ED showed a greater reduction in anhedonia (F_1,103 = 10.32, p = .002, partial η² = .09). RewP reward responses increased more (F_1,86 = 5.98, p = .02, partial η² = .07) for PCIT-ED, but a greater change in RewP was not significantly associated with a greater reduction in major depressive disorder symptoms (r = -.12, p > .4). Baseline RewP did not predict treatment change. LPPs to positive pictures did not change across treatment, but greater baseline LPPs to positive pictures predicted a higher likelihood of remission from major depressive disorder in children undergoing PCIT-ED (B = 0.14; SE = 0.07; odds ratio = 1.15; p = .03).

CONCLUSIONS

The ERP reward response improved in young children with depression during a treatment designed to enhance emotion development, providing evidence of target engagement of the neural systems associated with reward. Further, greater baseline LPP responses to positive pictures was associated with a greater likelihood of depression remission, suggesting that this ERP measure can predict which children are most likely to respond to treatment.

Mechanisms underlying remediation of depression-associated anxiety by chronic N-acetyl cysteine treatment

RATIONALE

Anxiety is one of the most comorbid conditions with major depressive disorder (MDD). Depression-associated anxiety often stems from the dysfunctional hypothalamic-pituitary-adrenal (HPA) axis and its altered regulation by the amygdala. Furthermore, MDD is associated with altered glutamatergic processing leading to anxiety and impaired regulation of the HPA axis. Recent studies have demonstrated that N-acetyl cysteine (NAC), a pleiotropic drug, exerts antidepressant-like effect by modulation of hippocampal functions, periterminal release of glutamate, and/or redox systems. However, the effects of NAC on depression-associated anxiety, HPA axis hyperactivity, and amygdalar dysfunctions are relatively unknown.

OBJECTIVES

Accordingly, we evaluated the effect of NAC on neonatal clomipramine (CLI)-induced adulthood anxiety and accompanying changes in plasma corticosterone levels, amygdalar volumes, neuronal/glial densities, levels of monoamines, and their metabolites in the amygdalar complex.

RESULTS

We found that chronic treatment with NAC reverses CLI-induced anhedonia and enhanced anxiety. Interestingly, attenuation of CLI-associated anxiety in NAC-treated rats were accompanied by a reversal of adrenal and spleen hypertrophy, and normalization of enhanced plasma corticosterone levels, indicating improved HPA axis functioning. Furthermore, NAC treatment was sufficient to reverse volumetric hypertrophy of basolateral amygdala (BLA), and altered noradrenaline (NA) metabolism in the amygdalar complex. The effects of NAC in the reversal of CLI-induced impairments were similar to that of fluoxetine (FLX).

CONCLUSIONS

We suggest that beneficial effects of NAC on antidepressive- and antianxiety-like behaviors are at least in part mediated via restoration of amygdalar and HPA axis functioning. Our results support the hypothesis that NAC might be evolved as a therapeutic strategy for reversal of amygdalar dysfunction in depression.

Developmental trajectories to reduced activation of positive valence systems: A review of biological and environmental contributions

Reduced activation of positive valence systems (PVS), including blunted neural and physiological responses to pleasant stimuli and rewards, has been shown to prospectively predict the development of psychopathology. Yet, little is known about how reduced PVS activation emerges across development or what implications it has for prevention. We review genetic, temperament, parenting, and naturalistic and laboratory stress research on neural measures of PVS and outline developmentally-informed models of trajectories of PVS activation. PVS function is partly heritable and appears to reflect individual differences in early-emerging temperament traits. Although lab-induced stressors blunt PVS activation, effects of parenting and naturalistic stress on PVS are mixed and depend on the type of stressor, developmental timing, and interactions amongst risk factors. We propose that there may be multiple, dynamic developmental trajectories to reduced PVS activation in which combinations of genes, temperament, and exposure to severe, prolonged, or uncontrollable stress may exert direct and interactive effects on PVS function. Critically, these risk factors may alter PVS developmental trajectories and/or PVS sensitivity to proximal stressors. Distinct factors may converge such that PVS activation proceeds along a typical, accelerated, chronically low, or stress-reactive trajectory. Finally, we present directions for future research with translational implications.

Plasticity of the Reward Circuitry After Early-Life Adversity: Mechanisms and Significance

Disrupted operation of the reward circuitry underlies many aspects of affective disorders. Such disruption may manifest as aberrant behavior including risk taking, depression, anhedonia, and addiction. Early-life adversity is a common antecedent of adolescent and adult affective disorders involving the reward circuitry. However, whether early-life adversity influences the maturation and operations of the reward circuitry, and the potential underlying mechanisms, remain unclear. Here, we present novel information using cutting-edge technologies in animal models to dissect out the mechanisms by which early-life adversity provokes dysregulation of the complex interactions of stress and reward circuitries. We propose that certain molecularly defined pathways within the reward circuitry are particularly susceptible to early-life adversity. We examine regions and pathways expressing the stress-sensitive peptide corticotropin-releasing factor (CRF), which has been identified in critical components of the reward circuitry and interacting stress circuits. Notably, CRF is strongly modulated by early-life adversity in several of these brain regions. Focusing on amygdala nuclei and their projections, we provide evidence suggesting that aberrant CRF expression and function may underlie augmented connectivity of the nucleus accumbens with fear/anxiety regions, disrupting the function of this critical locus of pleasure and reward.

Interactions between the combined genotypes of 5-HTTLPR and BDNF Val66Met polymorphisms and parenting on adolescent depressive symptoms: A three-year longitudinal study

BACKGROUND

The importance of multiple genes-environment interaction (G × E) has been highlighted in studies on depressive symptoms. 5-HTTLPR and BDNF Val66Met polymorphisms, with functional interconnection, have been implicated in the pathophysiology of depressive symptoms. However, little is understood about whether the interaction of 5-HTTLPR, BDNF Val66Met and parenting fits better with the epistatic or cumulative manner.

METHODS

865 adolescents (T1: M_age = 12.32, 50.2% girls) were included in a three-year interval longitudinal design. Standardized questionares about parenting and depressive symptoms were collected. Saliva samples were collected for genotyping.

RESULTS

Neither the concurrent nor longitudinal interaction of 5-HTTLPR, BDNF Val66Met and parenting (G × G × E) showed significant effects on depressive symptoms. The interaction between cumulative genotypes and positive parenting (CG × E) was significant, with the strong differential susceptibility model, for depressive symptoms concurrently but not longitudinally after statistical correction. Adolescents who carried 3 (i.e. SS and Val/Met, L allele and Val/Val) and 4 (i.e. SS and Val/Val), not 1 (i.e. L allele and Met/Met) or 2 cumulative susceptibility alleles (i.e. SS and Met/Met, L allele and Val/Met), reported fewer depressive symptoms if they had experienced higher levels of positive parenting, and more symptoms under lower levels of positive parenting.

LIMITATIONS

This study did not examine the 5-HTTLPR triallelic (rs25531) marker and did not include an external sample.

CONCLUSIONS

The combined effects of 5-HTTLPR and BDNF Val66Met polymorphisms functioned in a manner of cumulative rather than epistatic in response to positive parenting on early adolescent depressive symptoms.

Preschool-Onset Major Depressive Disorder is Characterized by Electrocortical Deficits in Processing Pleasant Emotional Pictures

Reductions in positive affect are a salient feature of preschool-onset major depressive disorder. Yet, little is known about the psychophysiological correlates of this blunted positive affect and whether reduced physiological responding to pleasant stimuli may differentiate depressed and healthy young children. 120 four-to-seven year old children with current depression and 63 psychiatrically healthy 4-to-7 year old children completed a simple picture-viewing task of pleasant and neutral pictures while event-related potentials (ERPs) were recorded. The early-childhood version of the Kiddie Schedule for Affective Disorders and Depression was used to establish psychiatric diagnoses. A one-way ANCOVA was used to test for group differences in response to pleasant and neutral pictures. Young children with depression showed a reduced response to pleasant vs. neutral pictures (LPP), after controlling for children's age (F(1,180) = 4.15, p = 0.04, η2 = 0.02). The LPP for the children with preschool-onset depression (M = 0.99, SE = 0.65) was significantly smaller than the LPP in the healthy group of young children (M = 3.27, SE = 0.90). This difference did not vary as a function of depression or anhedonia severity within the group with depression or the healthy children. Similar to older children and adolescents with depression, young children with depression display reductions in responsivity to pleasant stimuli as indexed by the LPP. These findings extend prior findings indicating a blunted response to pleasant stimuli in preschool- onset depression. Given the greater neuroplasticity of emotional response and regulation, these findings suggest clinical attention to emotional response to pleasure is an important target in preschool-onset depression. Clinical trial registration information: A Randomized Control Trial of PCIT-ED for Preschool Depression; http://clinicaltrials.gov/;NCT02076425.

Preschool Depression: a Diagnostic Reality

PURPOSE OF REVIEW

We review findings related to predictors, correlates, outcomes, and treatment of preschool depression that have been published in the last 3 years.

RECENT FINDINGS

Preschool depression displays a chronic course through late adolescence and is associated with temperamental and personality traits, poorer physical health, and negative parenting practices. Preschool depression predicts deficits into adolescence, including social difficulties and blunted neural response to rewards. Depressed preschoolers can experience suicidal ideation and behaviors and display an accurate understanding of the finality of death. A treatment for preschool depression has now been validated that uses the parent-child relationship to enhance emotion development and reduce depressive symptoms. Preschool depression is homotypic with depression that occurs later in life. Future work elucidating mechanisms through which preschool depression develops and informs the sub-groups for which particular treatments may be most effective will have considerable implications for prevention and early intervention.

Subcortical Volume Correlates of Psychological Distress in Early Adolescence

The hippocampus and amygdala have justifiably been the focus of much mental health research due to their putative roles in top-down processing control of emotion, fear, and anxiety. However, understanding the causal relationship between these regions and mental illness has been limited as current literature is lacking in the observation of neuro-structural changes preceding first episodes. Here, we report whole and sub-structural hippocampal and amygdala volume correlates of psychological distress in early adolescence. Automated hippocampal subfield and amygdala nuclei segmentation was carried out in 32 participants (12-13 years old) recruited for the Longitudinal Adolescent Brain Study (LABS) who had psychological distress scores measured by the Kessler-10. Partial correlation analyses revealed significant negative association between left whole amygdala volume and psychological distress. Sub-structure analysis revealed that smaller left hippocampal CA1 volume and left basal and accessory basal amygdala nuclei volumes were all significantly associated with higher levels of psychological distress. Four-month follow-up analysis also revealed an association between change in K10 and CA1 volume suggesting a continued relationship between this hippocampal substructure and psychological distress. Grey matter volume of subcortical sub-structures involved within the hippocampal-basolateral amygdala-prefrontal cortex loop are highly correlated and are significantly reduced in adolescents with higher levels of psychological distress, indicating these nuclei and subfields play an important role in the emergence of mental illness.

A tumultuous transition to motherhood: Altered brain and hormonal responses in mothers with postpartum depression

Postpartum depression (PPD) is a common but complex condition that is poorly understood and multifactorial in aetiology. It is a condition that can compromise the mother's care for her infant, which may pose challenges to the formation of the mother-infant bond and the infant's overall development. Past research has looked at abnormalities in the brain circuitry and hormonal profiles of mothers with PPD compared to non-depressed mothers. However, abnormalities in PPD that may specifically affect the mother's care of her infant have not been clearly assessed. Thus, the present review aims to synthesise studies of altered brain and hormonal responses in mothers with PPD in relation to their care of their infant. First, we review maternal brain responses and their relation to PPD symptomatology, focusing on the salience/fear network, reward/attachment network and default mode network. Next, we discuss oxytocin and hypothalamic-pituitary-adrenal axis hormones in the context of maternal behaviour and PPD. Finally, we synthesise these findings and propose how future studies may benefit from the combined study of both neural and hormonal activity to better understand the underlying neurobiology of maternal care in PPD.

Sex-Dependent Associations among Maternal Depressive Symptoms, Child Reward Network, and Behaviors in Early Childhood

Maternal depression is associated with disrupted neurodevelopment in offspring. This study examined relationships among postnatal maternal depressive symptoms, the functional reward network and behavioral problems in 4.5-year-old boys (57) and girls (65). We employed canonical correlation analysis to evaluate whether the resting-state functional connectivity within a reward network, identified through an activation likelihood estimation (ALE) meta-analysis of fMRI studies, was associated with postnatal maternal depressive symptoms and child behaviors. The functional reward network consisted of three subnetworks, that is, the mesolimbic, mesocortical, and amygdala–hippocampus reward subnetworks. Postnatal maternal depressive symptoms were associated with the functional connectivity of the mesocortical subnetwork with the mesolimbic and amygdala–hippocampus complex subnetworks in girls and with the functional connectivity within the mesocortical subnetwork in boys. The functional connectivity of the amygdala–hippocampus subnetwork with the mesocortical and mesolimbic subnetworks was associated with both internalizing and externalizing problems in girls, while in boys, the functional connectivity of the mesocortical subnetwork with the amygdala–hippocampus complex and the mesolimbic subnetworks was associated with the internalizing and externalizing problems, respectively. Our findings suggest that the functional reward network might be a promising neural phenotype for effects of maternal depression and potential intervention to nurture child behavioral development.

Hippocampal volume and depression among young children

Clinical depression can occur in young children as early as age three. This very early onset variant of depression shows the same clinical features with developmental adjustments as depression that onsets later in life. One robust neural feature of adult depression is reduced hippocampal volume. We measured hippocampal volume in a sample of 35 children aged 4-7 who were either in a clinical trial for preschool onset depression or were recruited from the community. We used T1 MPRAGE acquisitions on a Siemen's Scanner, with Freesurfer 5.3 used to segment the hippocampus. Depression was measured using the K-SADS early childhood (K-SADS-EC) to create a dimensional depression severity score and the Child Behavior Checklist (CBCL) Depression T-Score. Multilevel models indicated that greater depression severity as measured by either the CBCL Depression Score or the K-SADS-EC was associated with lower hippocampal volume, even controlling for total gray matter, maternal depression, income-to-needs ratio, and stressful life events. These data indicate evidence for reduced hippocampal volume among children with PO-MDD who were more severely depressed. Findings are consistent with the idea that hippocampal volume reductions are an early occurring associated neural marker of MDD, particularly for more severe depression.

Neural Indicators of Anhedonia: Predictors and Mechanisms of Treatment Change in a Randomized Clinical Trial in Early Childhood Depression

BACKGROUND

Early childhood depression is associated with anhedonia and reduced event-related potential (ERP) responses to rewarding or pleasant stimuli. Whether these neural measures are indicators of target engagement or treatment outcome is not yet known.

METHODS

We measured ERP responses to win and loss feedback in a guessing task and to pleasant versus neutral pictures in young (4.0-6.9 years of age) depressed children before and after randomization to either 18 weeks of Parent-Child Interaction Therapy-Emotion Development (PCIT-ED) treatment or waitlist (WL) control condition.

RESULTS

Analyses included reward positivity (RewP) data from 118 children randomized to PCIT-ED treatment (n = 60) or WL control condition (n = 58) at baseline and late positive potential (LPP) data from 99 children (44 PCIT-ED treatment vs. 55 WL control condition) at baseline. Children in the PCIT-ED group showed a greater reduction in anhedonia (F1,103 = 10.32, p = .002, partial η2 = .09). RewP reward responses increased more (F1,87 = 5.45, p = .02, partial η2 = .06) for PCIT-ED and a greater change in RewP was associated with a greater reduction in major depressive disorder symptoms (r = -.24, p = .05). Baseline RewP did not predict treatment change. LPPs to positive pictures did not change across treatment, but greater baseline LPPs to positive pictures predicted a higher likelihood of remission from major depressive disorder in the PCIT-ED group (B = 0.14; SE = 0.07; odds ratio = 1.15; p = .03).

CONCLUSIONS

The ERP reward response improved in young children with depression during a treatment designed to enhance emotion development, providing evidence of target engagement of the neural systems associated with reward. Further, greater baseline LPP responses to positive pictures were associated with a greater reduction in depression, suggesting that this ERP measure can predict which children are most likely to respond to treatment.

A Randomized Controlled Trial of Parent-Child Psychotherapy Targeting Emotion Development for Early Childhood Depression

OBJECTIVE

Clinical depression in children as young as age 3 has been validated, and prevalence rates are similar to the school-age disorder. Homotypic continuity between early and later childhood depression has been observed, with alterations in brain function and structure similar to those reported in depressed adults. These findings highlight the importance of identifying and treating depression as early as developmentally possible, given the relative treatment resistance and small effect sizes for treatments later in life. The authors conducted a randomized controlled trial of a dyadic parent-child psycho-therapy for early childhood depression that focuses on enhancing the child's emotional competence and emotion regulation.

METHOD

A modified version of the empirically tested parent-child interaction therapy with a novel "emotion development" module (PCIT-ED) was compared with a waiting list condition in a randomized controlled trial in 229 parent-child dyads with children 3-6.11 years of age. Both study arms lasted 18 weeks.

RESULTS

Children in the PCIT-ED group had lower rates of depression (primary outcome), lower depression severity, and lower impairment compared with those in the waiting list condition (Cohen's d values, >1.0). Measures of child emotional functioning and parenting stress and depression were significantly improved in the PCIT-ED group.

CONCLUSIONS

The findings from this randomized controlled trial of a parent-child psychotherapy for early childhood depression suggest that earlier identification and intervention in this chronic and relapsing disorder represents a key new pathway for more effective treatment. Manualized PCIT-ED, administered by master's-level clinicians, is feasible for delivery in community health settings.

Continuity and stability of preschool depression from childhood through adolescence and following the onset of puberty

BACKGROUND

A growing body of research now supports the validity, clinical significance, and long-term negative impact of depression occurring during the preschool period. However, the prospective continuity of depressive symptoms and risk for major depressive disorder (MDD) from childhood through adolescence for preschoolers experiencing this highly impairing disorder remains unexplored. Such information is likely to be critical for understanding the developmental continuity of preschool depression and whether it continues to be a salient risk factor for an MDD diagnosis following the transition into adolescence and the onset of biological changes associated with it (i.e., puberty).

METHODS

Subjects were participants in the Preschool Depression Study conducted at the Early Emotional Development Program at Washington University School of Medicine in St. Louis. Subjects and their parents completed baseline assessments that included comprehensive measures of psychopathology and development at baseline and up to 9 follow-up assessments between 2003 and 2017. N = 279 subjects had diagnostic and clinical data available for the preschool period and the early pubertal and/or later pubertal periods and were included in the analyses. There were N = 275 subjects assessed during the early pubertal period and N = 184 subjects assessed during the later pubertal period.

RESULTS

Preschool depression was a highly salient predictor of prepubertal and mid-to-post pubertal MDD. Across all modeled time points children with a history of preschool depression continued to demonstrate elevated levels of depressive symptoms from childhood through adolescence, suggesting a heightened trajectory of depressive symptoms relative to their same age peers.

CONCLUSION

Findings from the current study suggest that children with a history of preschool depression follow a trajectory of depression severity elevated relative to their same age peers from childhood through adolescence but with a similar shape over time. They also support the homotypic continuity of preschool depression into adolescence and the onset of puberty.

The Lifespan Human Connectome Project in Development: A large-scale study of brain connectivity development in 5-21 year olds

Recent technological and analytical progress in brain imaging has enabled the examination of brain organization and connectivity at unprecedented levels of detail. The Human Connectome Project in Development (HCP-D) is exploiting these tools to chart developmental changes in brain connectivity. When complete, the HCP-D will comprise approximately ∼1750 open access datasets from 1300 + healthy human participants, ages 5-21 years, acquired at four sites across the USA. The participants are from diverse geographical, ethnic, and socioeconomic backgrounds. While most participants are tested once, others take part in a three-wave longitudinal component focused on the pubertal period (ages 9-17 years). Brain imaging sessions are acquired on a 3 T Siemens Prisma platform and include structural, functional (resting state and task-based), diffusion, and perfusion imaging, physiological monitoring, and a battery of cognitive tasks and self-reports. For minors, parents additionally complete a battery of instruments to characterize cognitive and emotional development, and environmental variables relevant to development. Participants provide biological samples of blood, saliva, and hair, enabling assays of pubertal hormones, health markers, and banked DNA samples. This paper outlines the overarching aims of the project, the approach taken to acquire maximally informative data while minimizing participant burden, preliminary analyses, and discussion of the intended uses and limitations of the dataset.

Preschool- and School-Age Irritability Predict Reward-Related Brain Function

OBJECTIVE

Although chronic irritability in childhood is prevalent, impairing, and predictive of later maladjustment, its pathophysiology is largely unknown. Deficits in reward processing are hypothesized to play a role in irritability. The current study aimed to identify how the developmental timing of irritability during preschool- and school-age relates to reward-related brain function during school-age.

METHOD

Children's irritability was assessed during the preschool period (wave 1; ages 3.0-5.9 years) and 3 years later (wave 2; ages 5.9-9.6 years) using a clinical interview. At wave 2, children (N = 46; 28 female and 18 male) performed a monetary incentive delay task in which they received rewards, if they successfully hit a target, or no reward regardless of performance, during functional magnetic resonance imaging.

RESULTS

Children with more versus less severe preschool irritability, controlling for concurrent irritability, exhibited altered reward-related connectivity: right amygdala with insula and inferior parietal lobe as well as left ventral striatum with lingual gyrus, postcentral gyrus, superior parietal lobe, and culmen. Children with more versus less severe concurrent irritability, controlling for preschool irritability, exhibited a similar pattern of altered connectivity between left and right amygdalae and superior frontal gyrus and between left ventral striatum and precuneus and culmen. Neural differences associated with irritability were most evident between reward and no-reward conditions when participants missed the target.

CONCLUSION

Preschool-age irritability and concurrent irritability were uniquely associated with aberrant patterns of reward-related connectivity, highlighting the importance of developmental timing of irritability for brain function.