Separation anxiety: at the neurobiological crossroads of adaptation and illness

Individual differences in internalizing symptoms in late childhood: A variance decomposition into cortical thickness, genetic and environmental differences

The brain undergoes extensive development during late childhood and early adolescence. Cortical thinning is a prominent feature of this development, and some researchers have suggested that differences in cortical thickness may be related to internalizing symptoms, which typically increase during the same period. However, research has yielded inconclusive results. We utilized a new method that estimates the combined effect of individual differences in vertex-wise cortical thickness on internalizing symptoms. This approach allows for many small effects to be distributed across the cortex and avoids the necessity of correcting for multiple tests. Using a sample of 8763 children aged 8.9 to 11.1 from the ABCD study, we decomposed the total variation in caregiver-reported internalizing symptoms into differences in cortical thickness, additive genetics, and shared family environmental factors and unique environmental factors. Our results indicated that individual differences in cortical thickness accounted for less than 0.5% of the variation in internalizing symptoms. In contrast, the analysis revealed a substantial effect of additive genetics and family environmental factors on the different components of internalizing symptoms, ranging from 06% to 48% and from 0% to 34%, respectively. Overall, while this study found a minimal association between cortical thickness and internalizing symptoms, additive genetics, and familial environmental factors appear to be of importance for describing differences in internalizing symptoms in late childhood. RESEARCH HIGHLIGHTS: We utilized a new method for modelling the total contribution of vertex-wise individual differences in cortical thickness to internalizing symptoms in late childhood. The total contribution of individual differences in cortical thickness accounted for <0.5% of the variance in internalizing symptoms. Additive genetics and shared family environmental variation accounted for 17% and 34% of the variance in internalizing symptoms, respectively. Our results suggest that cortical thickness is not an important indicator for internalizing symptoms in childhood, whereas genetic and environmental differences have a substantial impact.

Maternal Labor Force Participation During the Child's First Year and Later Separation Anxiety Symptoms

Separation anxiety symptoms are frequent among preschool-aged children, but it is also a possible gateway for diagnosis of separation anxiety disorder. Early maternal employment after childbirth can increase the risk for the development of separation anxiety symptoms. From an economic perspective, however, securing employment is one effective strategy to ensure child well-being. This study investigated how mothers' participation in the labor force (vs. maternal leave) and the financial state of families when the child was 5 months old was prospectively associated with separation anxiety symptoms. This study is based on 1,295 Canadian families with children assessed longitudinally from 17 months to age 6 on their levels of separation anxiety. Separation anxiety was measured during face-to-face interviews with the mothers. Maternal labor force participation, financial status, and risk factors were measured at 5 months. Results adjusted for propensity scores and for sample weight revealed that children of working mothers, despite having sufficient income (n = 245, 18.9%), were at higher risk of separation anxiety during early childhood. In contrast, maternity leave was most beneficial for children's separation anxiety, whether they were in a family with sufficient income (n = 950, 73.4%) or temporary low income (n = 100, 7.7%). Children of mothers in maternity leave were at risk of heightened separation anxiety only if they experienced chronic economic hardship. Therefore, maternity leave uptake could help prevent the development of separation anxiety. Providing families with opportunity to care for the baby as their main occupation during this sensitive developmental period could help improve children's mental health.

Differential effects of generalized anxiety and separation anxiety on brain structural development during adolescence

Excessive anxiety is highly prevalent during childhood and adolescence, with detrimental effects on somatic and mental health, and quality of life. Although structural abnormalities in the brain have been found in people with anxiety disorders, whether anxiety affects the brain development of children and adolescents remains unknown. Here, we applied a multivariate approach to two single-site MRI datasets consisting of 733 and 775 participants aged 5-18 years. Using linear support vector regression and cross-validation, brain age is estimated by predicting the chronological age from the features that combine cortical thickness and surface area of 68 brain regions. We found that gray matter can predict the chronological age of children and adolescents with a low mean absolute error. Compared to specific brain network, the whole structural brain measures predicted brain age better. Importantly, adolescents with higher generalized anxiety and those with lower separation anxiety showed lower brain age, indicating a slow development of brain structures. The relationship between anxiety and brain age of youths could also be found in parent-reported separation anxiety. The findings highlight differential effects of different anxiety types on brain structural development and suggest that different types of anxiety during childhood and adolescence should be treated differently.

Caregiver's reports of their children's psychological symptoms after the start of the COVID-19 pandemic and caregiver's perceived stress in Turkey

PURPOSE

There is limited information about Turkish children's mental health during the COVID-19 outbreak. Here, in a Turkish community sample, we investigate the psychological symptoms in primary school children after the start of the COVID-19 outbreak according to caregivers and the caregivers' perceived stress levels.

MATERIALS AND METHODS

The sample was randomly selected from the primary schools in Denizli, Turkey. Denizli is a large city and the total population is around one-million. The study was conducted online. The caregivers responded to a sociodemographic and daily life during pandemic questionnaire and psychological symptoms screening form (which evaluated whether the children had any newly developed symptoms after the start of the COVID-19 outbreak) and the Perceived Stress Scale (PSS). One-thousand-seven-hundred-ninety-seven people were included in the study. Data was collected between 3 July and 31 August 2020.

RESULTS

Symptoms such as anhedonia, gets angry easily, fidgets around, sleeping problems, impulsivity, appetite problems, restlessness or nervousness, and feels sad can be seen more frequently than other symptoms in children. Caregivers' PSS scores were higher in mothers than fathers. An association was found between the PSS scores of the caregivers and all psychological symptoms questioned in the study for children, except for encopresis. Lower education level of the father, lower family income, having a child with a psychiatric disease, impaired sibling relationship, and impaired functionality at home were risk factors for higher caregivers' PSS scores.

CONCLUSION

It may be beneficial to take supportive measures in terms of protecting children's mental health.

Parental Occupational Exposure is Associated With Their Children's Psychopathology: A Study of Families of Israeli First Responders

OBJECTIVE

To examine the association between parental occupational exposure to traumatic events and their children's mental health in families of First Responders (FRs), a neglected area of research.

METHODS

In 208 families of Israeli FRs, children's symptoms and comorbidity patterns of seven psychiatric disorders were regressed on parental work-related variables, controlling for relevant covariates.

RESULTS

Having a father working as a FR and higher paternal exposure were associated with a greater number of separation anxiety and posttraumatic stress symptoms, respectively. Maternal exposure was associated with a greater number of symptoms of generalized anxiety, panic disorder, depression, and oppositional defiant disorder, and with increased odds of comorbid internalizing symptomatology.

CONCLUSIONS

Additional research on children of FRs is encouraged. An adaption to this understudied population of family-centered interventions available for military families could inform targeted prevention efforts.

Impact of ovariectomy and CO2 inhalation on microglia morphology in select brainstem and hypothalamic areas regulating breathing in female rats

The neural network that regulates breathing shows a significant sexual dimorphism. Ovarian hormones contribute to this distinction as, in rats, ovariectomy reduces the ventilatory response to CO2. Microglia are neuroimmune cells that are sensitive to neuroendocrine changes in their environment. When reacting to challenging conditions, these cells show changes in their morphology that reflect an augmented capacity for producing pro- and anti-inflammatory cytokines. Based on evidence suggesting that microglia contribute to sex-based differences in reflexive responses to hypercapnia, we hypothesized that ovariectomy and hypercapnia promote microglial reactivity in selected brain areas that regulate breathing. We used ionized calcium-binding-adapter molecule-1 (Iba1) immunolabeling to compare the density and morphology of microglia in the locus coeruleus (LC), the caudal medullary raphe, the caudal part of the nucleus of the tractus solitarius (cNTS), and the paraventricular nucleus of the hypothalamus (PVN). Tissue was obtained from SHAM (metaestrus) female rats or following ovariectomy. Rats were exposed to normocapnia or hypercapnia (5% CO2, 20 min). Ovariectomy and hypercapnia did not affect microglial density in any of the structures studied. Ovariectomy promoted a reactive phenotype in the cNTS and LC, as indicated by a larger morphological index. In these structures, hypercapnia had a relatively modest opposing effect; the medullary raphe or the PVN were not affected. We conclude that ovarian hormones attenuate microglial reactivity in CO2/H+ sensing structures. These data suggest that microglia may contribute to neurological diseases in which anomalies of respiratory control are associated with cyclic fluctuations of ovarian hormones or menopause.

A neurobiological framework of separation anxiety and related phenotypes

In the DSM-5, separation anxiety disorder (SAD) is newly classified in the chapter on anxiety, renewing research efforts into its etiology. In this narrative review, we summarize the current literature on the genetic, endocrine, physiological, neural and neuropsychological underpinnings of SAD per se, SAD in the context of panic disorder, separation anxiety symptoms, and related intermediate phenotypes. SAD aggregates in families and has a heritability of ~43%. Variants in the oxytocin receptor, serotonin transporter, opioid receptor µ1, dopamine D4 receptor and translocator protein genes have all been associated with SAD. Dysregulation of the hypothalamus-pituitary-adrenal axis, dysfunctional cortico-limbic interaction and biased cognitive processing seem to constitute further neurobiological markers of separation anxiety. Hypersensitivity to carbon dioxide appears to be an endophenotype shared by SAD, panic disorder and anxiety sensitivity. The identification of biological risk markers and its multi-level integration hold great promise regarding the prediction of SAD risk, maintenance and course, and in the future may allow for the selection of indicated preventive and innovative, personalized therapeutic interventions.

Diagnosis and Management of Anxiety Disorders

PURPOSE OF REVIEW

This article provides a synopsis of the current understanding of the pathophysiology of anxiety disorders, the biological and environmental risk factors that contribute to their development and maintenance, a review of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria, and a practical approach to the treatment of anxiety disorders in adults.

RECENT FINDINGS

Despite the ubiquity of anxiety, the evidence is that most individuals with an anxiety disorder are not identified and do not receive guideline-level care. In part, this may be because of the manifold clinical presentations of anxiety disorders and clinicians' lack of confidence in accurately diagnosing and treating these conditions, especially in nonpsychiatric settings. Anxiety disorders represent the complex interplay between biological, psychological, temperamental, and environmental factors. Converging lines of evidence point to dysfunction in regulating activity in the "threat circuit" in the brain as a putative common pathophysiology underlying anxiety disorders. Evidence-based treatments for anxiety disorders, such as cognitive-behavioral therapy and antidepressant medications, have been shown to regulate activity in this circuit, which consists of reciprocal connections between the dorsomedial prefrontal cortex, insula, and amygdala.

SUMMARY

Anxiety disorders are the most common class of emotional disorders and a leading cause of disability worldwide. A variety of effective treatment strategies are available, which may exert their therapeutic benefits from top-down or bottom-up modulation of the dysfunctional brain activity associated with anxiety disorders.

Reappraising Preclinical Models of Separation Anxiety Disorder, Panic Disorder, and CO2 Sensitivity: Implications for Methodology and Translation into New Treatments

Separation anxiety applies to multiple forms of distress responses seen in mammals during postnatal development, including separation from a caregiver. Childhood separation anxiety disorder is an important risk factor for developing panic disorder in early adulthood, and both conditions display an increased sensitivity to elevated CO₂ concentrations inhaled from the air. By interfacing epidemiological, genetic, and physiological knowledge with preclinical animal research models, it is possible to decipher the mechanisms that are central to separation anxiety and panic disorders while also suggesting possible therapies. Preclinical research models allow for environmentally controlled studies of early interferences with parental care. These models have shown that different forms of early maternal separation in mice and rats induce elevated CO₂ respiratory sensitivity, an important biomarker of separation anxiety and panic disorders. In mice, this is likely due to gene-environment interactions that affect multiple behavioural and physical phenotypes after exposure to this early adversity. Although several questions regarding the causal mechanism of separation anxiety and panic disorder remain unanswered, the identification and improved understanding of biomarkers that link these mental health conditions under the guise of preclinical research models in conjunction with human longitudinal cohort studies can help resolve these issues.

Early childhood trajectories of separation anxiety: Bearing on mental health, academic achievement, and physical health from mid-childhood to preadolescence

BACKGROUND

Separation anxiety disorder is the most prevalent childhood anxiety condition, but no study assessed children for separation anxiety at preschool age and followed them longitudinally and directly until mid-childhood/early adolescence.

METHODS

Multi-informant (children, teachers, family), multipoint (at age 8, 10, 12, 13) assessments of 1,290 children of the Quebec Longitudinal Study of Child Development, who had been categorized between age 1.5 and 6 into four specific separation anxiety trajectories (1, low-persistent; 2, low-increasing; 3, high-decreasing, and the less common: 4, high-increasing) by growth mixture modeling. Participants in the high-increasing trajectory were compared to participants in the other three trajectories for: (a) child's internalizing and externalizing problem behavior; (b) physical health; (c) academic achievement; (d) maternal anxiety.

RESULTS

Multivariate analyses of variance/covariance at separate time points showed the high-increasing trajectory mostly associated with: (a) higher internalizing, but not externalizing, behavior; (b) worse academic achievement (most consistently by comparisons to the normative low-persistent trajectory; (c) higher rates of maternal panic/agoraphobic anxiety; (d) worse physical health (most consistently by comparisons to the low-persistent trajectory). The high-increasing trajectory had twofold to threefold higher incidences of physical illnesses than the normative low-persistent group; this was specific for headaches at age 12 years, chronic asthma at age 10 and 13, and having received asthma-related medication during the past 12 months.

CONCLUSIONS

High-increasing separation anxiety in preschool maintains longitudinal relationships to independent health and academic outcomes, at least until preadolescence. This knowledge can inform the deployment of clinical resources at the earlier signs of the more impairing manifestations.