Suzanne King

Child’s stress hormone levels correlate with mother’s socioeconomic status and depressive state

BACKGROUND Individuals with lower socioeconomic status report greater exposure to stressful life events and a greater impact of these events on their lives than individuals with higher socioeconomic status, and this relationship between socioeconomic status and health begins at the earliest stages of life. To extend on these results, we performed a psychoneuroendocrine study of 217 children and 139 mothers. METHODS Salivary cortisol levels and cognitive function were assessed in children, and a semistructured phone interview measuring symptoms of stress and depression was conducted with their mothers. RESULTS Children with low socioeconomic status present significantly higher salivary cortisol levels than children with high socioeconomic status, and this socioeconomic status effect emerges as early as age 6. We also report that a childs cortisol level is significantly correlated with his or her mothers extent of depressive symptomatology. CONCLUSIONS These results offer a neurobiological determinant to the well-known association between socioeconomic status and health that begins early in life.

Can poverty get under your skin? Basal cortisol levels and cognitive function in children from low and high socioeconomic status

It is well known that individuals from more advantaged social classes enjoy better mental and physical health than do individuals within lower classes. Various mechanisms have been evoked to explain the association between socioeconomic status (SES) and health. One mechanism that has received particular attention in recent years is stress. It has been shown that individuals lower in SES report greater exposure to stressful life events and a greater impact of these events on their life than individuals higher in SES. In order to measure whether the development of the relationship between SES and mental health is sustained by exposure to high levels of glucocorticoids, we measured morning salivary cortisol levels as well as cognitive function (memory, attention, and language) in 307 children (from 6 to 16 years of age) from low versus high SES in the Montreal area in Canada. The results revealed that low SES children from 6 to 10 years old present significantly higher salivary cortisol levels when compared to children from high SES. This difference disappears at the time of school transition, and no SES differences are observed in salivary cortisol levels during high school. However, children from low and high SES do not differ with regard to memory or to attentional and linguistic functions. Also, mothers of low SES children reported higher feelings of depression and more unhealthy behaviors, while mothers of high SES children reported higher stress related to work or family transitions. Altogether, these results show that low SES in young children is related to increased cortisol secretion, although the impact of SES on cortisol secretion is absent after transition to high school. These data are interpreted within the context of the equalization process of class patterning. Four social explanatory factors are suggested to explain the disappearance of SES differences in basal cortisol levels after school transition, taking into account the influence of family environment on the childs secretion of stress hormones.

Prenatal stress and brain development.

Prenatal stress (PS) has been linked to abnormal cognitive, behavioral and psychosocial outcomes in both animals and humans. Animal studies have clearly demonstrated PS effects on the offsprings brain, however, while it has been speculated that PS most likely affects the brains of exposed human fetuses as well, no study has to date examined this possibility prospectively using an independent stressor (i.e., a stressful event that the pregnant woman has no control over, such as a natural disaster). The aim of this review is to summarize the existing animal literature by focusing on specific brain regions that have been shown to be affected by PS both macroscopically and microscopically. These regions include the hippocampus, amygdala, corpus callosum, anterior commissure, cerebral cortex, cerebellum and hypothalamus. We first discuss the mechanisms by which the effects of PS might occur. In particular, we show that maternal and fetal hypothalamic-pituitary-adrenal (HPA) axes, and the placenta, are the most likely candidates for these mechanisms. We see that, although animal studies have obvious advantages over human studies, the integration of findings in animals and the transfer of these findings to human populations remains a complex issue. Finally, we show how it is possible to circumvent these challenges by studying the effects of PS on brain development directly in humans, by taking advantage of natural or man-made disasters and assessing the impact and consequences of such stressful events on pregnant women and their offspring prospectively.

Project Ice Storm: Prenatal Maternal Stress Affects Cognitive and Linguistic Functioning in 5½-Year-Old Children

OBJECTIVE This was a prospective study designed to determine the extent to which the degree of exposure to prenatal maternal stress due to a natural disaster explains variance in the intellectual and language performance of offspring at age 5(1/2) while controlling for several potential confounding variables. METHOD Subjects were eighty-nine 5(1/2)-year-old children whose mothers were pregnant during a natural disaster: the January 1998 ice storm crisis in the Canadian province of Québec that resulted in power losses for 3 million people for as long as 40 days. In June 1998, women completed several questionnaires including those about the extent of objective stress (Storm 32) and subjective distress (Impact of Events Scale-Revised) experienced due to the storm. Their children were assessed with the Wechsler Preschool and Primary Scale of Intelligence-Revised (IQ) and Peabody Picture Vocabulary Test-Revised (language) at 5(1/2) years of age, and mothers completed assessments of recent life events and psychological functioning. RESULTS Children exposed in utero to high levels of objective stress had lower Full Scale IQs, Verbal IQs, and language abilities compared to children exposed to low or moderate levels of objective prenatal maternal stress; there were no effects of subjective stress or objective stress on Performance IQs. Trend analyses show that for all outcome variables except Block Design, there was a significant curvilinear association between objective stress and functioning. CONCLUSIONS Prenatal exposure to a moderately severe natural disaster is associated with lower cognitive and language abilities at 5(1/2) years of age.

Validation of a French version of the impact of event scale-revised.

Objective: This report presents a French translation and validation of the Impact of Event Scale-Revised (IES-R) in a population of women exposed to a natural disaster during or preceding pregnancy. Method: A total of 223 francophone women who were either pregnant at the time of the 1998 ice storm or who became pregnant shortly thereafter completed the IES-R and other questionnaires 6 months after the disaster. Results: The French IES-R has good internal consistency, with alpha coefficients ranging from 0.81 to 0.93 for its 3 subscales and total score. The test–retest reliability of the scale, although examined with another sample, proved to be satisfactory, with correlation coefficients ranging from 0.71 to 0.76 for its 3 subscales and total score. Its convergent validity with perceived life threat and general psychiatric symptoms was judged to be marginally acceptable. Finally, a principal components analysis was conducted and a 3-factor solution, which explained 56% of the variance, was retained: a hyperarousal factor (7 items), an avoidance factor (6 items), and an intrusion factor (6 items). Conclusions: The French version of the IES-R has satisfactory internal validity and test–retest reliability. Further, the factor structure of the translation was similar to the proposed theoretical structure of the IES-R.

The effects of prenatal maternal stress on children's cognitive development: Project Ice Storm

There exists considerable research on the effects of prenatal maternal stress on offspring. Animal studies, using random assignment to experimental and control groups, demonstrate the noxious effects of prenatal maternal stress on physical, behavioural and cognitive development. The generalizability of these results to humans is problematic given that cognitive attributions moderate reactions to stressors. In humans, researchers have relied upon maternal anxiety or exposure to life events as proxies for the stressors used with animals. Yet, the associations between maternal anxiety or potentially non-independent life events and problems in infants are confounded by genetic transmission of temperament from mother to child. We summarize the literature on prenatal maternal stress and infant cognitive development, leading to the conclusion that the human literature lacks the ability to separate the effects of the objective exposure to a stressor and the mothers subjective reaction. We then describe our prospective Project Ice Storm in which we are following 150 children who were exposed in utero to a natural disaster. We demonstrate significant effects of the objective severity of exposure on cognitive and language development at age two years with important moderating effects of the timing during pregnancy. The implications of our findings are discussed.

DNA methylation signatures triggered by prenatal maternal stress exposure to a natural disaster: Project Ice Storm.

Background Prenatal maternal stress (PNMS) predicts a wide variety of behavioral and physical outcomes in the offspring. Although epigenetic processes may be responsible for PNMS effects, human research is hampered by the lack of experimental methods that parallel controlled animal studies. Disasters, however, provide natural experiments that can provide models of prenatal stress. Methods Five months after the 1998 Quebec ice storm we recruited women who had been pregnant during the disaster and assessed their degrees of objective hardship and subjective distress. Thirteen years later, we investigated DNA methylation profiling in T cells obtained from 36 of the children, and compared selected results with those from saliva samples obtained from the same children at age 8. Results Prenatal maternal objective hardship was correlated with DNA methylation levels in 1675 CGs affiliated with 957 genes predominantly related to immune function; maternal subjective distress was uncorrelated. DNA methylation changes in SCG5 and LTA, both highly correlated with maternal objective stress, were comparable in T cells, peripheral blood mononuclear cells (PBMCs) and saliva cells. Conclusions These data provide first evidence in humans supporting the conclusion that PNMS results in a lasting, broad, and functionally organized DNA methylation signature in several tissues in offspring. By using a natural disaster model, we can infer that the epigenetic effects found in Project Ice Storm are due to objective levels of hardship experienced by the pregnant woman rather than to her level of sustained distress.

Childhood abuse and dissociative symptoms in adult schizophrenia

Dissociative symptoms, occurring in many psychiatric disorders including schizophrenia, are often preceded by traumatic experience. We hypothesized that various types of childhood trauma would correlate with levels of dissociative symptomatology in adult patients. Twenty-six patients completed the Dissociative Experiences Scale (DES) and the Childhood Trauma Questionnaire (CTQ). Dissociation was significantly correlated with emotional abuse (r=0.84, one-tailed p<0.001), and physical abuse (r=0.55, p<0.01). We suggest that emotional abuse may play an important role in the etiology of dissociation in schizophrenia.

Prenatal maternal stress from a natural disaster predicts dermatoglyphic asymmetry in humans.

Dermatoglyphic asymmetry of fingertip ridge counts is more frequent in schizophrenia patients than normal controls, and may reflect disruptions in fetal development during Weeks 14-22 when fingerprints develop. However, there are no data in humans linking specific adverse events at specific times to dermatoglyphic asymmetries. Our objective was to determine whether prenatal exposure to a natural disaster (1998 Quebec ice storm) during Weeks 14-22 would result in increased dermatoglyphic asymmetry in children, and to determine the roles of maternal objective stress exposure, subjective stress reaction, and postdisaster cortisol. Ridge counts for homologous fingers were scored for 77 children (20 target exposed [Weeks 14-22] and 57 nontarget exposed [exposed during other gestation weeks]). Children in the target group had more than 0.50 SD greater asymmetry than the nontarget group. Within the target group, children whose mothers had high subjective ice storm stress had significantly greater asymmetry than those with lower stress mothers, and maternal postdisaster cortisol had a significant negative correlation with the childrens dermatoglyphic asymmetry (r = -.56). Prenatal maternal stress during the period of fingerprint development results in greater dermatoglyphic asymmetry in their children, especially in the face of greater maternal distress.

Cortisol response to a psychosocial stressor in schizophrenia: blunted, delayed, or normal?

BACKGROUND Patients with schizophrenia may differ from healthy controls by having dysregulated physiological responses to stress. Our objective was to determine the extent to which cortisol reaction can discriminate between controls and schizophrenia patients while controlling for symptom severity, personality, body mass index (BMI) and smoking. METHOD 30 chronic schizophrenia patients and 30 matched controls underwent a modified version of the Trier Social Stress Test (TSST), consisting of public speaking and mental arithmetic. Heart rate, blood pressure, and salivary cortisol were measured repeatedly throughout the TSST. In addition, participants completed the NEO Personality Inventory (NEO-FFI), and were interviewed with the Brief Psychiatric Rating Scale (BPRS). RESULTS Both groups had a significant increase in heart rate and mean arterial pressure following the TSST. Results of a logistic regression suggests that patients can be discriminated from controls with a smaller change in cortisol between baseline and 15 min post-TSST, controlling for BMI and severity of positive symptoms. There was a trend for lower overall cortisol secretion in patients. CONCLUSIONS Despite demonstrable effects of the stressor on cardiac measures, schizophrenia patients tend to have smaller acute cortisol reaction to psychosocial stress. The significance of this conclusion for vulnerability-stress models of schizophrenia is discussed.