Lisa K. Mundy

Known Risk Factors for Violence Predict 12-Month-Old Infants’ Aggressiveness With Peers

This study tested the hypothesis that 12-month-old infants’ use of force against peers is associated with known risk factors for violence. We conducted a prospective longitudinal study, which included laboratory observations of firstborn British infants (N = 271) during simulated birthday parties. No gender differences in aggressiveness were observed. The infants’ observed aggressiveness was significantly correlated with mothers’ mood disorder during pregnancy and with mothers’ history of conduct problems. Infants’ observed aggressiveness was correlated with parents’ ratings of infants’ anger and aggression, which were also predicted by mothers’ mood disorder and history of conduct problems. Our findings indicate that infants at risk for serious aggression can already be identified when the motor ability to use physical force first enters the human repertoire.

The lifetime experience of traumatic events is associated with hair cortisol concentrations in community-based children

Adversity early in life can disrupt the functioning of the hypothalamic-pituitary-adrenal axis (HPAA) and increase risk for negative health outcomes. Recent research suggests that cortisol in scalp hair represents a promising measure of HPAA function. However, little is known about the relationship between early exposure to traumatic events and hair cortisol concentrations (HCC) in childhood, a critical period of HPAA development. The current study measured HCC in scalp hair samples collected from 70 community-based children (14 males, mean age=9.50) participating in the Imaging Brain Development in the Childhood to Adolescence Transition Study (iCATS). Data were also collected on lifetime exposure to traumatic events and current depressive symptoms. Lifetime exposure to trauma was associated with elevated HCC; however, HCC was not associated with current depressive symptoms. Consistent with some prior work, males were found to have higher HCC than females, although results should be treated with caution due to the small number of males who took part. Our findings suggest that hair cortisol may represent a biomarker of exposure to trauma in this age group; however, further study is necessary with a particular focus on the characterization of trauma and other forms of adversity.

Associations between early adrenarche, affective brain function and mental health in children

Early timing of adrenarche, associated with relatively high levels of Dehydroepiandrosterone (DHEA) in children, has been associated with mental health and behavioral problems. However, little is known about effects of adreneracheal timing on brain function. The aim of this study was to investigate the effects of early adrenarche (defined by high DHEA levels independent of age) on affective brain function and symptoms of psychopathology in late childhood (N = 83, 43 females, M age 9.53 years, s.d. 0.34 years). Results showed that higher DHEA levels were associated with decreased affect-related brain activity (i) in the mid-cingulate cortex in the whole sample, and (ii) in a number of cortical and subcortical regions in female but not male children. Higher DHEA levels were also associated with increased externalizing symptoms in females, an association that was partly mediated by posterior insula activation to happy facial expressions. These results suggest that timing of adrenarche is an important moderator of affect-related brain function, and that this may be one mechanism linking early adrenarche to psychopathology.

Transitions Study of predictors of illness progression in young people with mental ill health: study methodology

An estimated 75% of mental disorders begin before the age of 24 and approximately 25% of 13–24‐year‐olds are affected by mental disorders at any one time. To better understand and ideally prevent the onset of post‐pubertal mental disorders, a clinical staging model has been proposed that provides a longitudinal perspective of illness development. This heuristic model takes account of the differential effects of both genetic and environmental risk factors, as well as markers relevant to the stage of illness, course or prognosis. The aim of the Transitions Study is to test empirically the assumptions that underpin the clinical staging model. Additionally, it will permit investigation of a range of psychological, social and genetic markers in terms of their capacity to define current clinical stage or predict transition from less severe or enduring to more severe and persistent stages of mental disorder.

Reduced frontal white matter volume in children with early onset of adrenarche

While there is growing evidence that puberty affects brain development, very little is known about the structural brain changes associated with dehydroepiandrosterone (DHEA), an adrenal hormone that exhibits dramatic increases during adrenarche, the earliest phase of puberty. Moreover, no research has investigated whether relatively early exposure to DHEA (i.e., early adrenarche) during this period is associated with differences in brain structure. We ran a whole-brain voxel-based morphometry analysis on T1-weighted magnetic resonance imaging brain scans to compare gray (GMV) and white matter volumes (WMV) between children experiencing relatively early (n=41) vs. relatively late (n=44) adrenarche. We also investigated the correlations between GMV or WMV and DHEA levels, and finally, tested for sex differences in group and correlation analyses. We observed reduced frontal WMV in a cluster located on the left corona radiata in children experiencing earlier adrenarche. In addition, WMV in this area was negatively correlated with DHEA levels. We did not observe any effect of gender in both the group and the correlation analyses. Early onset of adrenarche (as defined by relatively early exposure to DHEA) may be associated with differences in the development of frontal white matter tracts.

Adrenarche and the Emotional and Behavioral Problems of Late Childhood

PURPOSE Mental and behavioral disorders increase in prevalence with the passage through puberty. Yet the first symptoms for many children emerge between seven and 11 years, before the pubertal rise in gonadal hormones. A possibility that symptom onset may be linked to the adrenarchal rise in androgens has been little explored. METHODS The Childhood to Adolescence Transition Study recruited a stratified random sample of 1,239 eight-nine year olds from primary schools in Melbourne, Australia. Saliva samples were assayed for dehydroepiandrosterone, dehydroepiandrosterone-sulphate (DHEA-S), and testosterone. Emotional and behavioral problems were assessed through parental report on the Strengths and Difficulties Questionnaire. RESULTS In males, high levels of all androgens were associated with greater total difficulties and peer problems. Higher dehydroepiandrosterone and testosterone were associated with emotional symptoms and DHEA-S with conduct problems. In females, DHEA-S was associated with peer problems. CONCLUSIONS In late childhood, androgens are associated with emotional and behavioral problems in males, raising a possibility that the adrenarchal transition plays a contributing role. If so, the late primary school years may prove to be an important phase for preventing the onset of mental health and behavioral problems in boys.

Depression, immune function, and early adrenarche in children

Despite consistent findings of an association between depression and immunity in adult and adolescent populations, little is known about the nature of this relationship at earlier ages. Studies of children have yielded mixed results, suggesting methodological confounds and/or the presence of significant moderating factors. Timing of adrenarche, the first phase of puberty that occurs during late childhood, is a plausible moderator of the depression-immunity relationship in late childhood due to its associations with both the immune system and psychological wellbeing. We hypothesized that: (1) a depression-immunity association exists in children, (2) this association is moderated by adrenarcheal timing, and, (3) this association is also moderated by gender. Data were drawn from a nested study of 103 participants (62 females, Mage=9.5, age range: 8.67-10.21 years) participating in a population based cohort study of the transition from childhood to adolescence (across puberty). Participants in this nested study completed the Childrens Depression Inventory 2 (CDI-2) and provided morning saliva samples to measure immune markers (i.e., C-reactive protein, CRP; and secretory immunoglobulin A, SIgA). Using hierarchical regression, inflammation measured by CRP was positively associated with the negative mood/physical symptoms (NM/PS) subscale (β=0.23, t=2.33, p=0.022) of the CDI-2. A significant interaction effect of SIgA x adrenarcheal timing was found for NM/PS (β=-0.39, t=-2.19, p=0.031) and Interpersonal Problems (β=-0.47, t=-2.71, p=0.008). SIgA and NM/PS were positively associated for relatively late developers. SIgA and Interpersonal Problems were positively associated for late developers, and negatively associated for early developers. We suggest that both sets of findings might be partially explained by the immunosuppressive effect of the hormonal changes associated with earlier adrenarche, namely testosterone. These results also suggest that adrenarcheal timing has an effect on the association between depression and immunity, and is therefore an important measure in research with younger populations. Future research should utilize longitudinal designs to demonstrate direction of influence of variables, and use a broader range of pro- and anti-inflammatory markers.

Associations between dehydroepiandrosterone (DHEA) levels, pituitary volume, and social anxiety in children.

Early timing of adrenarche, associated with relatively high levels of dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S) in children, has been linked with mental health problems, particularly anxiety. However, little is known about possible neurobiological mechanisms underlying this association. The pituitary gland is a key component of the hypothalamic-pituitary-adrenal (HPA) axis, the activation of which triggers the onset of adrenarche. The purpose of this study was to examine the extent to which pituitary gland volume mediated the relationship between levels of DHEA/DHEA-S relative to age (i.e., adrenarcheal timing) and symptoms of anxiety in 95 children (50 female, M age 9.50 years, SD 0.34 years). Relatively high DHEA and DHEA-S (DHEA/S) levels were found to be associated with larger pituitary gland volumes. There was no significant direct effect of relative DHEA/S levels on overall symptoms of anxiety. However, results supported an indirect link between relatively high DHEA/S levels and symptoms of social anxiety, mediated by pituitary gland volume. No sex differences were observed for any relationship. Our findings suggest that neurobiological mechanisms may be partly responsible for the link between relatively early adrenarche and anxiety symptoms in children. One possible mechanism for this finding is that an enlarged pituitary gland in children experiencing relatively advanced adrenarche might be associated with hyper-activity/reactivity of the HPA axis. Further research is needed to understand the role of stress in the link between adrenarcheal timing and HPA-axis function, especially in relation to the development of anxiety symptoms in children and adolescents.

Self-reported parenting style is associated with children's inflammation and immune activation

Family environments and parenting have been associated with inflammation and immune activation in children and adolescents; however, it remains unclear which specific aspects of parenting drive this association. In this study, we cross-sectionally examined the association between 5 discrete parenting styles and inflammation and immune activation in late childhood. Data were drawn from 102 families (55 with female children, mean age 9.50 years, SD = 0.34) participating in the Imaging Brain Development in the Childhood to Adolescence Transition Study. Children provided saliva samples from which inflammation (C-reactive protein) and immune competence/activation (secretory immunoglobulin A) were measured. Parents completed the Alabama Parenting Questionnaire, which measures 5 aspects of parenting style—positive parental involvement, positive disciplinary techniques, consistency in disciplinary techniques, corporal punishment, and monitoring and supervision. Results showed that higher scores on the poor parental monitoring scale were associated with higher levels of both inflammation and immune activation in children. This study highlights parental monitoring and supervision as a specific aspect of parenting behavior that may be important for children’s physical and mental health.

Pain and learning in primary school: a population-based study

Abstract Despite the frequency of pain among children, little is known about its effects on learning and school outcomes. The objective of this study was to quantify the association of pain and academic achievement while taking into account the presence of co-occurring emotional symptoms. A population-based stratified random sample of 1239 students aged 8 to 9 years from primary schools in Melbourne, Australia, was recruited for the Childhood to Adolescence Transition Study. Children indicated sites of pain that had lasted for a day or longer in the past month using a pain manikin. Depressive- and anxiety-related symptoms were assessed using child-reported items. National assessment results for reading and numeracy were used to measure academic achievement. Sixty-five percent of children reported pain in at least 1 body site and 16% reported chronic pain. Increasing number of pain sites was associated with poorer reading scores in a dose–response fashion (&bgr; = −3.1; 95% confidence interval −4.9 to −1.3; P < 0.001). The association was only partly attenuated when adjusting for emotional symptoms (&bgr; = −2.6; 95% confidence interval −4.5 to −0.8; P < 0.001) and was not moderated by emotional symptoms. Children with chronic pain were a year behind their peers in both reading and numeracy. Among primary school students, pain was associated with lower reading scores even after adjusting for the presence of emotional symptoms. Although population-based longitudinal studies will be required to ascertain consistency and possible causality, grounds exist for considering pain and emotional symptoms in the assessment of children with reading difficulties.