Kathy Hegadoren

Default mode network connectivity as a predictor of post-traumatic stress disorder symptom severity in acutely traumatized subjects

Objective:  The goal of this study was to investigate the relationship between default mode network connectivity and the severity of post‐traumatic stress disorder (PTSD) symptoms in a sample of eleven acutely traumatized subjects.

Stress hormones: how do they measure up?

Stress as a stimulus is integral to dynamic homeostatic functioning. However, evidence of its potentially deleterious effects on health is mounting. The impetus to understand the mechanisms that underlie stress-related negative health outcomes and prevent the development of stress-related disorders has never been greater. Symptom severity and subjective levels of stress, although frequently assessed in studies of stress in nursing research, may not provide adequate data to fully understand the pervasive effects of chronic or overwhelming stress associated with stress disorders. The measurement of stress hormones such as cortisol can help identify bodily changes that are stressor specific, people at risk for development of stress-related disorders, and the efficacy of interventions aimed at stress reduction. Cortisol, as the peripheral output of one of the major stress response systems, possesses several properties that make its measurement highly useful for investigations of stress. This article discusses some of the biological mechanisms involved in the stress response, why cortisol is commonly measured, and issues and approaches in cortisol measurement.

The role of β-endorphin in the pathophysiology of major depression

A role for beta-endorphin (beta-END) in the pathophysiology of major depressive disorder (MDD) is suggested by both animal research and studies examining clinical populations. The major etiological theories of depression include brain regions and neural systems that interact with opioid systems and beta-END. Recent preclinical data have demonstrated multiple roles for beta-END in the regulation of complex homeostatic and behavioural processes that are affected during a depressive episode. Additionally, beta-END inputs to regulatory pathways involving feeding behaviours, motivation, and specific types of motor activity have important implications in defining the biological foundations for specific depressive symptoms. Early research linking beta-END to MDD did so in the context of the hypothalamic-pituitary-adrenal (HPA) axis activity, where it was suggested that HPA axis dysregulation may account for depressive symptoms in some individuals. The primary aims of this paper are to use both preclinical and clinical research (a) to critically review data that explores potential roles for beta-END in the pathophysiology of MDD and (b) to highlight gaps in the literature that limit further development of etiological theories of depression and testable hypotheses. In addition to examining methodological and theoretical challenges of past clinical studies, we summarize studies that have investigated basal beta-END levels in MDD and that have used challenge tests to examine beta-END responses to a variety of experimental paradigms. A brief description of the synthesis, location in the CNS and behavioural pharmacology of this neuropeptide is also provided to frame this discussion. Given the lack of clinical improvement observed with currently available antidepressants in a significant proportion of depressed individuals, it is imperative that novel mechanisms be investigated for antidepressant potential. We conclude that the renewed interest in elucidating the role of beta-END in the pathophysiology of MDD must be paralleled by consensus building within the research community around the heterogeneity inherent in mood disorders, standardization of experimental protocols, improved discrimination of POMC products in analytical techniques and consistent attention paid to important confounds like age and gender.

Effects of trauma-related cues on pain processing in posttraumatic stress disorder: an fMRI investigation.

BACKGROUND Imaging studies of pain processing in primary psychiatric disorders are just emerging. This study explored the neural correlates of stress-induced analgesia in individuals with posttraumatic stress disorder (PTSD). It combined functional magnetic resonance imaging (fMRI) and the traumatic script-driven imagery symptom provocation paradigm to examine the effects of trauma-related cues on pain perception in individuals with PTSD. METHODS The study included 17 patients with PTSD and 26 healthy, trauma-exposed controls. Participants received warm (nonpainful) or hot (painful) thermal stimuli after listening to a neutral or a traumatic script while they were undergoing an fMRI scan at a 4.0 T field strength. RESULTS Between-group analyses revealed that after exposure to the traumatic scripts, the blood oxygen level-dependent (BOLD) signal during pain perception was greater in the PTSD group than the control group in the head of the caudate. In the PTSD group, strong positive correlations resulted between BOLD signal and symptom severity in a number of brain regions previously implicated in stress-induced analgesia, such as the thalamus and the head of the caudate nucleus. Trait dissociation as measured by the Dissociative Experiences Scale correlated negatively with the right amygdala and the left putamen. LIMITATIONS This study included heterogeneous traumatic experiences, a different proportion of military trauma in the PTSD versus the control group and medicated patients with PTSD. CONCLUSION These data indicate that in patients with PTSD trauma recall will lead in a state-dependent manner to greater activation in brain regions implicated in stress-induced analgesia. Correlational analyses lend support to cortical hyperinhibition of the amygdala as a function of dissociation.

All Our Babies Cohort Study: recruitment of a cohort to predict women at risk of preterm birth through the examination of gene expression profiles and the environment

BackgroundPreterm birth is the leading cause of perinatal morbidity and mortality. Risk factors for preterm birth include a personal or familial history of preterm delivery, ethnicity and low socioeconomic status yet the ability to predict preterm delivery before the onset of preterm labour evades clinical practice. Evidence suggests that genetics may play a role in the multi-factorial pathophysiology of preterm birth. The All Our Babies Study is an on-going community based longitudinal cohort study that was designed to establish a cohort of women to investigate how a womens genetics and environment contribute to the pathophysiology of preterm birth. Specifically this study will examine the predictive potential of maternal leukocytes for predicting preterm birth in non-labouring women through the examination of gene expression profiles and gene-environment interactions.Methods/DesignCollaborations have been established between clinical lab services, the provincial health service provider and researchers to create an interdisciplinary study design for the All Our Babies Study. A birth cohort of 2000 women has been established to address this research question. Women provide informed consent for blood sample collection, linkage to medical records and complete questionnaires related to prenatal health, service utilization, social support, emotional and physical health, demographics, and breast and infant feeding. Maternal blood samples are collected in PAXgene™ RNA tubes between 18-22 and 28-32 weeks gestation for transcriptomic analyses.DiscussionThe All Our Babies Study is an example of how investment in clinical-academic-community partnerships can improve research efficiency and accelerate the recruitment and data collection phases of a study. Establishing these partnerships during the study design phase and maintaining these relationships through the duration of the study provides the unique opportunity to investigate the multi-causal factors of preterm birth. The overall All Our Babies Study results can potentially lead to healthier pregnancies, mothers, infants and children.

The effects of estradiol on central serotonergic systems and its relationship to mood in women.

Lifetime prevalence rates of depression are higher in women than men. Because this gender disparity appears after the onset of puberty and declines after menopause, gonadal hormones may play a role in womens increased vulnerability to dysphoric states. Estrogens have powerful effects beyond their role in reproduction. Fluctuations in estrogen occur naturally throughout the reproductive years and can be associated with disruptions in mood. Treatment for depression with exogenous estrogen has produced equivocal results. To shed light on the complex interactions among estrogens, serotonin, and mood, we briefly examine (a) central serotonin systems and their relationship to mood and mood disorders, (b) nonreproductive effects of estrogens on those systems, (c) potential points of intersection between serotonin systems and estrogens, and (d) research into the use of exogenous estrogen in depression in women. In conclusion, we reiterate the call for carefully controlled research into the etiology and treatment of depression in women.

Influence of interpersonal violence on maternal anxiety, depression, stress and parenting morale in the early postpartum: a community based pregnancy cohort study

BackgroundResearch has shown that exposure to interpersonal violence is associated with poorer mental health outcomes. Understanding the impact of interpersonal violence on mental health in the early postpartum period has important implications for parenting, child development, and delivery of health services. The objective of the present study was to determine the impact of interpersonal violence on depression, anxiety, stress, and parenting morale in the early postpartum.MethodsWomen participating in a community-based prospective cohort study (n = 1319) completed questionnaires prior to 25 weeks gestation, between 34–36 weeks gestation, and at 4 months postpartum. Women were asked about current and past abuse at the late pregnancy data collection time point. Postpartum depression, anxiety, stress, and parenting morale were assessed at 4 months postpartum using the Edinburgh Postnatal Depression Scale, the Spielberger State Anxiety Index, the Cohen Perceived Stress Scale, and the Parenting Morale Index, respectively. The relationship between interpersonal violence and postpartum psychosocial health status was examined using Chi-square analysis (p < 0.05) and multivariable logistic regression.ResultsApproximately 30% of women reported one or more experience of interpersonal violence. Sixteen percent of women reported exposure to child maltreatment, 12% reported intimate partner violence, and 12% reported other abuse. Multivariable logistic regression analysis found that a history of child maltreatment had an independent effect on depression in the postpartum, while both child maltreatment and intimate partner violence were associated with low parenting morale. Interpersonal violence did not have an independent effect on anxiety or stress in the postpartum.ConclusionThe most robust relationships were seen for the influence of child maltreatment on postpartum depression and low parenting morale. By identifying women at risk for depression and low parenting morale, screening and treatment in the prenatal period could have far-reaching effects on postpartum mental health thus benefiting new mothers and their families in the long term.

Neural correlates and predictive power of trait resilience in an acutely traumatized sample: a pilot investigation.

OBJECTIVE Resilience refers to the ability to thrive despite adversity and is defined as a multidimensional phenomenon, spanning internal locus of control, sense of meaning, social problem-solving skills, and self-esteem. We aimed to investigate the predictive value of resilience for the development of posttraumatic stress disorder (PTSD) and to examine the neural correlates mediating the relationship between resilience and recovery from a traumatic event in acutely traumatized subjects. We hypothesized that resilience would mediate the relationship between childhood trauma and posttraumatic recovery. METHOD We conducted a prospective study with 70 acutely traumatized subjects with DSM-IV PTSD recruited at the emergency department, assessing PTSD symptom severity at 3 time points within the first 3 months posttrauma. Scores for childhood trauma as assessed with the Childhood Trauma Questionnaire and trait resilience as assessed with the Connor-Davidson Resilience Scale were used as predictors of symptom severity. A subsample of 12 subjects additionally underwent a functional 4 Tesla magnetic resonance imaging scan 2 to 4 months posttrauma. We employed the traumatic script-driven imagery paradigm to assess the correlations between trait resilience and blood oxygen level-dependent (BOLD) response. The study was conducted from 2003 to 2007. RESULTS Resilience predicted PTSD symptom severity at 5 to 6 weeks (β = -0.326, P = .01) as well as at 3 months (β = -0.423, P = .003) posttrauma better than childhood trauma. Resilience essentially mediated the relationship between childhood trauma and posttraumatic adjustment. Resilience scores were positively correlated with BOLD signal strength in the right thalamus as well as the inferior and middle frontal gyri (Brodmann area 47). CONCLUSIONS This pilot investigation revealed a significant relationship between resilience and emotion regulation areas during trauma recall in an acutely traumatized sample. Resilience was established as a significant predictor of PTSD symptom severity and mediated the influence of childhood trauma on posttraumatic adjustment.

Cortisol patterns of depressed mothers and their infants are related to maternal–infant interactive behaviours

Background: Postpartum depression (PPD) reduces maternal–infant interaction quality, stresses infants and mothers, and is linked to adverse child social–emotional and cognitive developmental outcomes. Objectives: A hypothesised mechanism for these observed relationships is the stress-related over-activation of the hypothalamic–pituitary–adrenal (HPA) axis and resultant altered cortisol patterns. While cortisol levels of mothers and infants are strongly correlated, environmental, maternal, infant and maternal–infant interactive factors may also contribute to altered cortisol patterns. Thus, the objective of this study is to use Barnard’s Child Health Assessment Model to explore the influences on maternal and infant diurnal cortisol patterns for matched pairs of mothers and infants affected by postpartum depression. Method: Secondary analyses were conducted on data collected from mothers and their infants affected by symptoms of PPD (n = 53). Multiple regression models were undertaken to study mothers’ and infants’ diurnal cortisol patterns using area under the curve analysis. Results: Having a preterm child predicted both an increase in overall cortisol levels (p = .01) and a reduction in the daily decline (p = .02) in cortisol patterns for mothers. Difficult life circumstances (p = .04) also predicted a reduction in mothers’ expected daily decline in cortisol. For infants, maternal–infant interaction qualities including cognitive growth-fostering (p = .03) and socioemotional growth fostering (p = .02) reduced overall cortisol levels and increased the daily decline in cortisol, respectively. Conclusion: For mothers, preterm birth was the most robust predictor of elevated cortisol levels. For infants, more optimal maternal–infant interactions predicted lower levels of infant cortisol. Future research should examine interactions among infant temperament, maternal responsiveness and infant cortisol patterns.

Critical feminist narrative inquiry: advancing knowledge through double-hermeneutic narrative analysis.

Critical feminist narrative inquiry is informed by the theoretical triangulation of critical, feminist, and symbolic interactionist perspectives. We first locate this approach within narrative research and identify the epistemological underpinnings and assumptions supporting this innovative methodology. The analytic and interpretive objectives and processes involved to achieve a double-hermeneutic narrative analysis are detailed. We conclude by proposing that this novel approach is suitable to advance knowledge about the nature and context of individual experiences, to expose circumstances leading to social injustice and health inequities, and ultimately to contribute to improved health outcomes for traditionally silenced, marginalized, or vulnerable populations.