Similarity in saliva cortisol measures in monozygotic twins and the influence of past major depression

Prenatal depression, fetal neurobehavior, and infant temperament: Novel insights on early neurodevelopment from a socioeconomically disadvantaged Indian cohort

This article extends the research focusing on the early origins of psychopathology into the prenatal period, by exploring the association between maternal prenatal depression and offspring (fetal and infant) neurobehavior. The sample is recruited from a rural population in South India where women in the third trimester of pregnancy were assessed for depression and the heart rate responses of their fetuses to extrinsically applied vibroacoustic stimuli were studied. At 2 months postbirth, infant temperament and cortisol responsivity to immunization were assessed. The association between maternal prenatal depression and fetal responsivity to vibroacoustic stimulation, and infant responsivity to immunization, was U shaped with higher levels of responsivity noted in the offspring of mothers with very high and very low depression scores, and lower levels noted in the offspring of mothers with moderate depression scores. Maternal prenatal depression was not associated with infant temperament. The findings highlight the importance of environmental influences in the developmental origins of neurobehavior, suggesting that such differences, not evident at baseline, may emerge upon exposure to stressors. The study also emphasizes the need for further investigation in low- and middle-income contexts by providing preliminary evidence of the differing patterns of association observed between high- and low-income populations.

Hair Cortisol in Twins: Heritability and Genetic Overlap with Psychological Variables and Stress-System Genes

Hair cortisol concentration (HCC) is a promising measure of long-term hypothalamus-pituitary-adrenal (HPA) axis activity. Previous research has suggested an association between HCC and psychological variables, and initial studies of inter-individual variance in HCC have implicated genetic factors. However, whether HCC and psychological variables share genetic risk factors remains unclear. The aims of the present twin study were to: (i) assess the heritability of HCC; (ii) estimate the phenotypic and genetic correlation between HPA axis activity and the psychological variables perceived stress, depressive symptoms, and neuroticism; using formal genetic twin models and molecular genetic methods, i.e. polygenic risk scores (PRS). HCC was measured in 671 adolescents and young adults. These included 115 monozygotic and 183 dizygotic twin-pairs. For 432 subjects PRS scores for plasma cortisol, major depression, and neuroticism were calculated using data from large genome wide association studies. The twin model revealed a heritability for HCC of 72%. No significant phenotypic or genetic correlation was found between HCC and the three psychological variables of interest. PRS did not explain variance in HCC. The present data suggest that HCC is highly heritable. However, the data do not support a strong biological link between HCC and any of the investigated psychological variables.

Adolescent internalizing symptoms and negative life events: the sensitizing effects of earlier life stress and cortisol

Although adolescence is marked by increased negative life events and internalizing problems, few studies investigate this association as an ongoing longitudinal process. Moreover, while there are considerable individual differences in the degree to which these phenomena are linked, little is known about the origins of these differences. The present study examines early life stress (ELS) exposure and early-adolescent longitudinal afternoon cortisol level as predictors of the covariation between internalizing symptoms and negative life events across high school. ELS was assessed by maternal report during infancy, and the measure of cortisol was derived from assessments at ages 11, 13, and 15 years. Life events and internalizing symptoms were assessed at ages 15, 17, and 18 years. A two-level hierarchical linear model revealed that ELS and cortisol were independent predictors of the covariation of internalizing symptoms and negative life events. Compared to those with lower levels of ELS, ELS-exposed adolescents displayed tighter covariation between internalizing symptoms and negative life events. Adolescents with lower longitudinal afternoon cortisol displayed tighter covariation between negative life events and internalizing symptoms, while those with higher cortisol demonstrated weaker covariation, partially due to increased levels of internalizing symptoms when faced with fewer negative life events.

A review of selected candidate endophenotypes for depression

Endophenotypes are proposed to occupy an intermediate position in the pathway between genotype and phenotype in genetically complex disorders such as depression. To be considered an endophenotype, a construct must meet a set of criteria proposed by Gottesman and Gould (2003). In this qualitative review, we summarize evidence for each criterion for several putative endophenotypes for depression: neuroticism, morning cortisol, frontal asymmetry of cortical electrical activity, reward learning, and biases of attention and memory. Our review indicates that while there is strong support for some depression endophenotypes, other putative endophenotypes lack data or have inconsistent findings for core criteria.

Microbial community profiling of human saliva using shotgun metagenomic sequencing

Human saliva is clinically informative of both oral and general health. Since next generation shotgun sequencing (NGS) is now widely used to identify and quantify bacteria, we investigated the bacterial flora of saliva microbiomes of two healthy volunteers and five datasets from the Human Microbiome Project, along with a control dataset containing short NGS reads from bacterial species representative of the bacterial flora of human saliva. GENIUS, a system designed to identify and quantify bacterial species using unassembled short NGS reads was used to identify the bacterial species comprising the microbiomes of the saliva samples and datasets. Results, achieved within minutes and at greater than 90% accuracy, showed more than 175 bacterial species comprised the bacterial flora of human saliva, including bacteria known to be commensal human flora but also Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, and Gamma proteobacteria. Basic Local Alignment Search Tool (BLASTn) analysis in parallel, reported ca. five times more species than those actually comprising the in silico sample. Both GENIUSand BLAST analyses of saliva samples identified major genera comprising the bacterial flora of saliva, but GENIUS provided a more precise description of species composition, identifying to strain in most cases and delivered results at least 10,000 times faster. Therefore, GENIUS offers a facile and accurate system for identification and quantification of bacterial species and/or strains in metagenomic samples.

Menstrual mood disorders are associated with blunted sympathetic reactivity to stress

OBJECTIVE

Few studies have directly compared women with a menstrually related mood disorder (MRMD) with women who have suffered from depression for stress reactivity phenotypes. It is unclear whether blunted responses to stress in women with a MRMD reflect a unique phenotype of MRMDs or may be explained by a history of depression.

METHODS

We assessed cardiovascular reactivity to stress in four groups: 1) Women with a MRMD without a history of depression (n=37); 2) women with a MRMD plus a history of depression (n=26); 3) women without a MRMD and without a history of depression (n=43); and 4) women without a MRMD but with a history of depression (n=20).

RESULTS

Women with a MRMD showed blunted myocardial (heart rate and cardiac index) reactivity to mental stress compared to non-MRMD women, irrespective of histories of depression. Hypo-reactivity to stress predicted greater premenstrual symptom severity in the entire sample. Women with a MRMD showed blunted norepinephrine and diastolic blood pressure stress reactivity relative to women with no MRMD, but only when no history of depression was present. Both MRMD women and women with depression histories reported greater negative subjective responses to stress relative to their non-MRMD and never depressed counterparts.

CONCLUSION

Our findings support the assertion that a blunted stress reactivity profile represents a unique phenotype of MRMDs and also underscore the importance of psychiatric histories to stress reactivity. Furthermore, our results emphasize the clinical relevance of myocardial hypo-reactivity to stress, since it predicts heightened premenstrual symptom severity.

Effects of mood and rumination on cortisol levels in daily life: an ambulatory assessment study in remitted depressed patients and healthy controls

The influence of naturally occurring emotional and cognitive experiences on hypothalamic-pituitary-adrenal axis (HPAA) activity is still underinvestigated, particularly in clinical populations. The present study examined effects of mood and rumination on cortisol levels in daily life in remitted depressed patients with recurrent episodes or a chronic precourse (n=31) and healthy controls (n=32). Ambulatory assessment of subjective variables (valence, calmness, energetic-arousal, ruminative self-focus), daily stressors, and saliva cortisol samples was performed five times a day on two consecutive workdays, whereby cortisol was collected 20min after the subjective assessments. In addition, depressive symptoms and trait rumination (brooding, reflection) were measured retrospectively. Multilevel models revealed that remitted depressed patients showed lower cortisol activity compared to healthy controls. Depressive symptoms and trait rumination did not predict HPAA activity, whereas, by controlling for daily stressors, higher daily means of ruminative self-focus and lower daily means of valence, energetic arousal and calmness were associated with higher daily cortisol levels. Separate analyses per group revealed that mean daily ruminative self-focus predicted higher cortisol in both samples. In contrast, lower daily means of calmness, but also of valence and energetic arousal, were significantly linked to higher cortisol output only in healthy controls, but not in the patient sample. These findings indicate that naturally occurring rumination and low mood are associated with increased activation of the HPAA in daily life. Moreover, our data revealed a potentially reduced mood-cortisol coupling in remitted recurrent depression, possibly indicating that during the course of recurrent depression HPAA activation might become less responsive toward subtle emotional experiences in natural contexts.

Neurobiological markers of familial risk for depression

Major depression is associated with a wide range of neurobiological disturbances, including anomalies in the structure and function of cortical and subcortical gray matter and dysregulation of the HPA axis. In this chapter, we review research demonstrating that many of these abnormalities are also present in never-depressed offspring of adults with recurrent depression and discuss how such findings might reflect dysfunctional neuroregulatory systems that precede the onset of this disorder. We also briefly discuss candidate genes and environmental factors that have been posited to be directly involved in the transmission of neural and HPA-axis abnormalities from depressed parents to their offspring, and we review how, by obtaining a better understanding of the neurobiological markers of depression risk, we can facilitate the development of targeted strategies for the prevention and treatment of major depression.

Impact of a prenatal cognitive-behavioral stress management intervention on salivary cortisol levels in low-income mothers and their infants

Recent findings suggest that elevated stress levels during the pre- and postpartum period are related to poor maternal and infant health outcomes; yet, few studies have prospectively examined the efficacy of stress management interventions on regulating stress levels among mothers and their infants. The current study examined whether a prenatal cognitive behavioral stress management (CBSM) intervention would be effective in regulating salivary cortisol (a biological marker of stress) and self-reported stress levels among mothers and their infants at six and 18 months postpartum, relative to two control groups. Our sample was comprised of predominantly Spanish-speaking, low-income women (80%; mean age=25±5 years) who were screened for depression during their second trimester of pregnancy (M=16±5 weeks of gestation). Women at high risk for depression [i.e., having either a past history of major depression or current elevated symptoms of depression (≥16 on CES-D)] were randomized to either a CBSM group (n=24) or a usual care (UC) group (n=33), while a low risk comparison (LRC) group (n=29) was comprised of women not meeting either depression criteria. ANCOVA analyses demonstrated that: (1) infants of women in the CBSM and LRC groups had significantly lower cortisol levels than infants of women in the UC group at six months postpartum (p<.001); and (2) women in the CBSM group had lower cortisol levels than women in the UC group at 18 months postpartum (p<.01). These results suggest that prenatal CBSM interventions may be efficacious in regulating biological markers of stress among mothers and their infants, thereby decreasing their risk for developing health complications over time.

The hypothalamic-pituitary-adrenal axis and serotonin abnormalities: a selective overview for the implications of suicide prevention

Suicidal behavior and mood disorders are one of the world's largest public health problems. The biological vulnerability for these problems includes genetic factors involved in the regulation of the serotonergic system and stress system. The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates the body's response to stress and has complex interactions with brain serotonergic, noradrenergic and dopaminergic systems. Corticotropin-releasing hormone and vasopressin act synergistically to stimulate the secretion of ACTH that stimulates the biosynthesis of corticosteroids such as cortisol from cholesterol. Cortisol is a major stress hormone and has effects on many tissues, including on mineralocorticoid receptors and glucocorticoid receptors in the brain. Glucocorticoids produce behavioral changes, and one important target of glucocorticoids is the hypothalamus, which is a major controlling center of the HPA axis. Stress plays a major role in the various pathophysiological processes associated with mood disorders and suicidal behavior. Serotonergic dysfunction is a well-established substrate for mood disorders and suicidal behavior. Corticosteroids may play an important role in the relationship between stress, mood changes and perhaps suicidal behavior by interacting with 5-HT1A receptors. Abnormalities in the HPA axis in response to increased levels of stress are found to be associated with a dysregulation in the serotonergic system, both in subjects with mood disorders and those who engage in suicidal behavior. HPA over-activity may be a good predictor of mood disorders and perhaps suicidal behavior via abnormalities in the serotonergic system.

Salivary cortisol in depressed patients versus control persons: a systematic review and meta-analysis

The pathophysiology of depression has been associated to dysregulation of the hypothalamic-pituitary-adrenal axis and the use of salivary cortisol measures is increasingly being incorporated into research. The aim of the present study was to investigate whether salivary cortisol differs for patients with depression and control persons. We did a systematic review with sequential meta-analysis and meta-regression according to the PRISMA Statement based on comprehensive database searches for studies of depressed patients compared to control persons in whom salivary cortisol was measured. Twenty case-control studies, including 1354 patients with depression and 1052 control persons were identified. In a random-effects meta-analysis salivary cortisol was increased for depressed patients as compared to control persons on average 2.58 nmol/l (95% C.I.: 0.95-4.21) p=0.002 in the morning and on average 0.27 nmol/l (95% C.I.: 0.03-0.51) p=0.03 in the evening. In a fixed-effects model the mean difference was 0.58 nmol/l (95% C.I.). Study sequential cumulative meta-analyses suggested random error for the finding of this rather small difference between groups. The reference intervals for morning salivary cortisol in depressed patients (0-29 nmol/l) and control persons (1-23 nmol/l) showed substantial overlap suggesting lack of discriminative capacity. These results should be interpreted with caution as the heterogeneity for the morning analysis was large and a funnel plot, suggested presence of bias. Further, in meta-regression analyses higher intra-assay coefficients of variation in cortisol kits (p=0.07) and mean age (p=0.08) were associated with a higher mean difference of morning salivary cortisol between depressed and controls, while gender and depression severity were not. Based on the available studies there is not firm evidence for a difference of salivary cortisol in depressed patients and control persons and salivary cortisol is unable to discriminate between persons with and without depression.

Histories of major depression and premenstrual dysphoric disorder: Evidence for phenotypic differences

This study examined unique versus shared stress and pain-related phenotypes associated with premenstrual dysphoric disorder (PMDD) and prior major depressive disorder (MDD). Sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA)-axis measures were assessed at rest and during mental stress, as well as sensitivity to cold pressor and tourniquet ischemic pain tasks in four groups of women: (1) non-PMDD with no prior MDD (N=18); (2) non-PMDD with prior MDD (N=9); (3) PMDD with no prior MDD (N=17); (4) PMDD with prior MDD (N=10). PMDD women showed blunted SNS responses to stress compared to non-PMDD women, irrespective of prior MDD; while women with prior MDD showed exaggerated diastolic blood pressure responses to stress versus never depressed women, irrespective of PMDD. However, only in women with histories of MDD did PMDD women have lower cortisol concentrations than non-PMDD women, and only in non-PMDD women was MDD associated with reduced cold pressor pain sensitivity. These results suggest both unique phenotypic differences between women with PMDD and those with a history of MDD, but also indicate that histories of MDD may have special relevance for PMDD.

High cortisol levels in the offspring of parents with bipolar disorder during two weeks of daily sampling

OBJECTIVES

The hypothalamic-pituitary-adrenal (HPA) axis is compromised in major depression, bipolar disorder (BD), and in the offspring of parents with major depression. Less is known about the offspring of parents with BD (FH+). The present project provides follow-up to a previous study showing that the adolescent (mean age 16.7 years) FH+ offspring had higher salivary cortisol levels than the offspring of parents with no mental disorder (FH-) throughout the day in their natural environment, and that girls had higher cortisol levels than boys (Ellenbogen MA, Hodgins S, Walker C-D, Adam S, Couture S. Daytime cortisol and stress reactivity in the offspring of parents with bipolar disorder. Psychoneuroendocrinology 2006; 31: 1164-1180). The goal of the present study was to determine whether FH+ offspring, approximately two years later, continued to exhibit elevated cortisol levels relative to FH- offspring during two weeks of daily sampling.

METHODS

The present study examined salivary cortisol levels in 24 (18.3 +/- 2.6 years) FH+ and 22 (18.0 +/- 2.3 years) FH- offspring who are part of the same longitudinal cohort as the previous study. Saliva was collected at 1300 h and 1500 h in the natural environment of the offspring during 14 consecutive days.

RESULTS

Multilevel modelling analyses indicated that FH+ offspring had higher afternoon levels of cortisol in their natural environment than FH- offspring, but group differences in slope and gender differences were not found.

CONCLUSIONS

The FH+ offspring exhibited increased daytime secretion of cortisol that, at the level of the group, persisted into late adolescence and young adulthood. Perhaps this change in HPA functioning is associated with an increased vulnerability for the development of an affective disorder.

Allostasis and the human brain: Integrating models of stress from the social and life sciences

We draw on the theory of allostasis to develop an integrative model of the current stress process that highlights the brain as a dynamically adapting interface between the changing environment and the biological self. We review evidence that the core emotional regions of the brain constitute the primary mediator of the well-established association between stress and health, as well as the neural focus of wear and tear due to ongoing adaptation. This mediation, in turn, allows us to model the interplay over time between context, current stressor exposure, internal regulation of bodily processes, and health outcomes. We illustrate how this approach facilitates the integration of current findings in human neuroscience and genetics with key constructs from stress models from the social and life sciences, with implications for future research and the design of interventions targeting individuals at risk.

Quantification of Circadian Phase Shifts with the Cross‐Correlation Technique

This paper concerns the applicability of the cross-correlation technique for the assessment of shifts of the circadian system (e.g., caused by night work). Melatonin and cortisol profiles of 52 healthy young men were ascertained during two 24 h phase assessment procedures. The first was performed after three consecutive day shifts, and the second was performed one week later on 24 men again after three day shifts and on 28 men after three night shifts, where adaptation to night work was accelerated by bright light. The cross-correlation technique that relies on the processing of all the measured data of a whole profile, as compared to the differences between temporal parameters determined with a conventional method, provided reliable estimates of the phase shifts. Its applicability is restricted to time series with similar profiles assessed at different times and to observation periods of a full diurnal cycle (in the case of substantial shifts) with equally distributed measures, but it is applicable to raw data and available in common statistical packages (e.g., SPSS, SAS, BMDP).

HPA axis hyperactivity and cardiovascular mortality in mood disorder inpatients

Depression is associated with an increased risk of cardiovascular disease (CVD), coronary heart disease (CHD) and cardiac death. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis function is frequent in major depression and hypercortisolemia may be a mediating factor in these relationships. The aim of this study was to assess HPA axis function measured with the dexamethasone suppression test (DST) in relation to CVD and CHD mortality in a cohort of 382 inpatients with mood disorder admitted to the department of Psychiatry at the Karolinska University Hospital between 1980 and 2000. Death certificates ascertained that 75 patients had died of cardiovascular disease and 30 patients of CHD during the mean follow-up of 18 years. DST non-suppression and higher baseline serum cortisol predicted CVD death. In male inpatients with mood disorder, the DST non-suppressor status was significantly associated with CVD death but not with CHD death. In depressed female inpatients the DST non-suppression was not associated with cardiovascular mortality. Baseline serum cortisol and post-dexamethasone serum cortisol levels at 4:00 p.m. showed a trend to be higher in female CVD/CHD victims. Effect of aging on HPA axis functioning was shown in male CHD deaths. HPA axis dysregulation may be a mediating factor between depression and increased risk of cardiovascular death in male mood disorder inpatients indicating that HPA-axis hyperactivity is a long term risk factor for cardiovascular mortality.

Persistence of abnormal cortisol levels in elderly persons after recovery from major depression

BACKGROUND

Cortisol hypersecretion is characteristic of acute clinical depression, but little is known in fully recovered, non-treated elderly persons with a lifetime history of depression. This study was designed to examine patterns of diurnal cycle of cortisol in an elderly cohort without current depression or treatment for depression according to whether the person has or has not experienced a previous episode of depression or co-morbid depression with anxiety.

METHODS

Cortisol secretion was evaluated in 162 community-dwelling elderly on a stressful and a non-stressful day (basal level). Past depression and anxiety disorders were assessed using a standardized psychiatric examination based on DSM-IV criteria (the Mini International Neuropsychiatric Interview).

RESULTS

Antidepressant-free persons with a history of non-co-morbid major depression (6.8% of the sample) showed basal cortisol hypersecretion compared to those with depression and anxiety (8.6%) or controls. Several hours after exposure to a stressful situation, controls showed a sustained increase in cortisol secretion, which was not observed in persons with a history of depression. Persons with a history of depression with anxiety showed a similar cortisol secretion at baseline to controls but a heightened response to stressful situation; a pattern comparable to that observed in subjects with pure anxiety disorders (16.7%).

CONCLUSION

An abnormal HPA response persists even after effective treatment for depression. A history of co-morbid depression and anxiety gives rise to changes characteristic of anxiety alone. Our findings suggest that cortisol abnormalities may be trait markers for vulnerability to depression and for the differentiation of depression and depression with co-morbid anxiety.

Salivary cortisol in unaffected twins discordant for affective disorder

Dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a biological endophenotype for affective disorders. In the present study the hypothesis that a high genetic liability to affective disorder is associated with higher cortisol levels was tested in a cross-sectional high-risk study. Healthy monozygotic (MZ) and dizygotic (DZ) twins with (High-Risk twins) and without (Low-Risk twins) a co-twin history of affective disorder were identified through nationwide registers. Awakening and evening salivary cortisol levels were compared between the 190 High- and Low-Risk twins. The 109 High-Risk twins had significantly higher evening cortisol levels than the 81 Low-Risk MZ twins, also after adjustment for age, sex, and the level of subclinical depressive symptoms. No significant difference was found in awakening cortisol levels between High-Risk and Low-Risk twins. In conclusion, a high genetic liability to affective disorder was associated with a higher evening cortisol level, but not with awakening cortisol level. Future prospective family, high-risk and twin studies are needed to decide whether abnormalities in the HPA axis can be identified as an endophenotype of affective disorder.

HPA-axis hyperactivity and mortality in psychotic depressive disorder: preliminary findings

BACKGROUND

The excess mortality associated with depressive disorders has been most often attributed to risks for suicide but diverse findings indicate that depressive disorders also increase risks for cardiovascular (CV) mortality. Among the possible mediators is the hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity that characterizes many cases of relatively severe depressive disorder and severity is characteristic of psychotic depressive disorder.

METHODS

The following describes a 17-year mortality follow-up of 54 patients with Research Diagnostic Criteria (RDC) psychotic major depression or schizoaffective, mainly affective, depression. All had baseline assessments that included a 1mg dexamethasone suppression test with post-dexamethasone samples at 8 a.m., 4 p.m. and 11 p.m.

RESULTS

Regression analyses showed that both greater age and higher maximum post-dexamethasone cortisol concentrations predicted deaths due to CV causes (t=4.01, p<0.001 and t=3.03, p=0.004, respectively). The 4 who died from CV disease had a mean (SD) post-dexamethasone cortisol concentration of 18.0 (6.0)microg/dl while the mean (SD) value for the remaining 50 patients was 7.6 (6.6)microg/dl (t=3.03, df=53, p=0.004). Regression analyses showed the 11 p.m. post-dexamethasone value to be predictive of suicide (t=2.05, p=0.048).

CONCLUSIONS

Conclusions should be tentative because an earlier follow-up of a more heterogeneous, but larger, sample did not find a relationship between DST results and CV mortality, and because only 4 CV deaths occurred in the present study. HPA-axis hyperactivity is probably only one of a number of factors that link depressive disorder to CV mortality.

Susceptibility to depression expressed as alterations in cortisol day curve: a cross-twin, cross-trait study

OBJECTIVE

To examine, using a cross-twin cross-trait design, the hypotheses 1) that the genetic and environmental susceptibility to depression is expressed, in part, as alterations in cortisol day curves and 2) that cortisol abnormalities are not merely the consequence of depressive states or the stressors associated with its onset. Alteration of diurnal secretion of cortisol is a possible endophenotype of depression, as depressed patients show alterations in cortisol dynamics over the day.

METHODS

Salivary cortisol measurements were obtained in a sample of 279 twin pairs at 10 random times a day for 5 days. A structured clinical interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition) axis I mood disorder (SCID) was administered. Using multilevel regression analysis, the moderating influence of a lifetime diagnosis of depression in the co-twin on the association between time of day and cortisol concentrations in the proband twin was examined.

RESULTS

Diurnal variation in cortisol in the proband twin differed as a function of lifetime diagnosis of depression in the co-twin. In addition, this moderating effect was significantly stronger for dizygotic than for monozygotic twins.

CONCLUSIONS

Probands of co-twins with lifetime depression have a different diurnal cortisol profile than those without, suggesting that altered hypothalamic-pituitary-adrenal axis functioning is an indicator of depression susceptibility.

Interfacial instabilities affect microfluidic extraction of small molecules from non-Newtonian fluids

As part of a project to develop an integrated microfluidic biosensor for the detection of small molecules in saliva, practical issues of extraction of analytes from non-Newtonian samples using an H-filter were explored. The H-filter can be used to rapidly and efficiently extract small molecules from a complex sample into a simpler buffer. The location of the interface between the sample and buffer streams is a critical parameter in the function of the H-filter, so fluorescence microscopy was employed to monitor the interface position; this revealed apparently anomalous fluorophore diffusion from the samples into the buffer solutions. Using confocal microscopy to understand the three-dimensional distribution of the fluorophore, it was found that the interface between the non-Newtonian sample and Newtonian buffer was both curved and unstable. The core of the non-Newtonian sample extended into the Newtonian buffer and its position was unstable, producing a fluorescence intensity profile that gave rise to the apparently anomalously fast fluorophore transport. These instabilities resulted from the pairing of rheologically dissimilar fluid streams and were flowrate dependent. We conclude that use of non-Newtonian fluids, such as saliva, in the H-filter necessitates pretreatment to reduce viscoelasticity. The interfacial variation in position, stability and shape caused by the non-Newtonian samples has substantial implications for the use of biological samples for quantitative analysis and analyte extraction in concurrent flow extraction devices.

Persistent alterations in biological profiles in women with abuse histories: influence of premenstrual dysphoric disorder

OBJECTIVE

To examine dysregulation in biological measures associated with histories of abuse in women and whether women with premenstrual dysphoric disorder (PMDD) differ in their dysregulation.

DESIGN

Twenty-five women meeting prospective criteria for PMDD and 42 non-PMDD controls underwent structured interview to determine abuse histories and lifetime Axis I diagnoses, excluding those with current Axis I disorders or using medications.

MAJOR OUTCOME MEASURES

Plasma cortisol and norepinephrine (NE), heart rate (HR), blood pressure (BP), and vascular resistance index (VRI) were assessed at rest and in response to mental stress.

RESULTS

A greater proportion of PMDD women had prior abuse compared with non-PMDD women. Regardless of PMDD status, all abused women had lower plasma NE and higher HRs and tended to have lower plasma cortisol at rest and during stress. Abused women also reported more severe daily emotional and physical symptoms. Greater VRI and BP at rest and during stress were seen only in PMDD women with abuse.

CONCLUSION

There is persistent dysregulation in stress-responsive systems in all abused women that cannot be accounted for by current psychiatric illness or medications, and PMDD women may be differentially more vulnerable to the impact of abuse on measures reflecting alpha-adrenergic receptor function.

Neurosteroids in the context of stress: implications for depressive disorders

Animal models indicate that the neuroactive steroids 3alpha,5alpha-THP (allopregnanolone) and 3alpha,5alpha-THDOC (allotetrahydroDOC) are stress responsive, serving as homeostatic mechanisms in restoring normal GABAergic and hypothalamic-pituitary-adrenal (HPA) function following stress. While neurosteroid increases to stress are adaptive in the short term, animal models of chronic stress and depression find lower brain and plasma neurosteroid concentrations and alterations in neurosteroid responses to acute stressors. It has been suggested that disruption in this homeostatic mechanism may play a pathogenic role in some psychiatric disorders related to stress. In humans, neurosteroid depletion is consistently documented in patients with current depression and may reflect their greater chronic stress. Women with the depressive disorder, premenstrual dysphoric disorder (PMDD), have greater daily stress and a greater rate of traumatic stress. While results on baseline concentrations of neuroactive steroids in PMDD are mixed, PMDD women have diminished functional sensitivity of GABA(A) receptors and our laboratory has found blunted allopregnanolone responses to mental stress relative to non-PMDD controls. Similarly, euthymic women with histories of clinical depression, which may represent a large proportion of PMDD women, show more severe dysphoric mood symptoms and blunted allopregnanolone responses to stress versus never-depressed women. It is suggested that failure to mount an appropriate allopregnanolone response to stress may reflect the price of repeated biological adaptations to the increased life stress that is well documented in depressive disorders and altered allopregnanolone stress responsivity may also contribute to the dysregulation seen in HPA axis function in depression.

Hypothalamic-pituitary-adrenal axis function in dissociative disorders, post-traumatic stress disorder, and healthy volunteers

BACKGROUND

This study investigated basal and stress-induced hypothalamic-pituitary-adrenal (HPA)-axis alterations in dissociative disorders (DDs).

METHODS

Forty-six subjects with DD without lifetime post-traumatic stress disorder (PTSD), 35 subjects with PTSD, and 58 healthy comparison (HC) subjects, free of current major depression, were studied as inpatients. After a 24-hour urine collection and hourly blood sampling for ambient cortisol determination, a low-dose dexamethasone suppression test was administered, followed by the Trier Social Stress Test.

RESULTS

The DD group had significantly elevated urinary cortisol compared with the HC group, which was more pronounced in the absence of lifetime major depression, whereas the PTSD and HC groups did not differ. The DD group demonstrated significantly greater resistance to, and faster escape from, dexamethasone suppression compared with the HC group, whereas the PTSD and HC groups did not differ. The three groups did not differ in cortisol stress reactivity, but both psychiatric groups demonstrated a significant inverse correlation between dissociation severity and cortisol reactivity, after controlling for all other symptomatology. The PTSD subgroup with comorbid DD tended to have blunted stress reactivity compared with the HC group.

CONCLUSIONS

The study demonstrates a distinct pattern of HPA-axis dysregulation in DDs, emphasizing the importance of further study of stress-response systems in dissociative psychopathology.

Depression in Mothers

Whether one takes a biological, psychological, or psychosocial perspective, depression in mothers raises concerns about risks for the development of psychopathology in the children. This review addresses the complexity of that risk and the essential role of development in a model that explains processes of transmission. This article addresses the following aims: (a) to provide convincing evidence that depression in mothers is an important topic for clinical psychologists; (b) to summarize current theoretical models of mechanisms of risk for the development of psychopathology in children of depressed mothers and the status of empirical support for those models; (c) to examine the theoretical bases and current status of evidence for moderators of this risk; (d) to argue for the advantages to be gained from a developmental psychopathology perspective on this topic; and (e) to point to future directions for theory, research, and practice.

Cortisol and adrenocorticotropic hormone responses to naloxone in subjects with high and low neuroticism

BACKGROUND

Neuroticism is a highly heritable personality trait that is a risk factor for certain affective and anxiety disorders. Studies link neuroticism with alterations in the Hypothalamic-Pituitary-Adrenal (HPA) stress response. We interrogated HPA axis dynamics as a function of neuroticism, employing the opioid receptor antagonist, naloxone.

METHODS

Subjects were assigned to either high or low neuroticism groups on the basis of Revised Neuroticism, Extraversion, Openness Personality Inventory (NEO-PI-R) scores and received naloxone hydrochloride (0, 125 microg/kg, and 375 microg/kg). Serum adrenocorticotropic hormone (ACTH) and cortisol levels were monitored.

RESULTS

Significant, dose-dependent differences in cortisol response were observed between neuroticism groups, whereas no differences were observed in ACTH. The low neuroticism group demonstrated a dose-dependent cortisol response with a plateau at the 125 microg/kg dose of naloxone. In contrast, the high neuroticism group demonstrated a graded cortisol response to all doses of naloxone.

CONCLUSIONS

These findings show that neuroticism is associated with altered cortisol responses to opioid receptor blockade, suggesting that alterations in HPA axis function already exist in persons at increased risk for certain depressive and anxiety disorders.

Saliva cortisol and response to dexamethasone in children of depressed parents

BACKGROUND

Major depression (MDD) is heritable, and children of depressed parents are at higher risk for the development of depression. However, depression in a parent might also act as a stressor leading to increased activation of neuroendocrine stress circuits. To address this question we examined saliva cortisol in children whose parents have a history of MDD.

METHODS

We recruited 15 families with one parent with MDD (26 prepubertal children) and 16 control families without history of parental MDD (32 prepubertal children). All parents and children underwent Structured Clinical Interview for DSM-IV and Kiddie Schedule For Affective Disorders And Schizophrenia interviews, respectively. Families were asked to collect morning, afternoon, and bedtime saliva samples for 4 days for 2 weeks. At bedtime of the 3rd day, dexamethasone was administered. Two doses, standard and low, were used in each family.

RESULTS

The majority of children demonstrated no psychiatric diagnosis. Children with MDD parents showed higher cortisol basally and higher cortisol after both 25 mg and 5 mg dexamethasone. However, this effect occurred predominantly in children whose parents were currently depressed. There were strong correlations for cortisol between parents and children (r = 52 in depressed; r = 499 in control).

CONCLUSIONS

Elevated cortisol and impaired feedback seemed to reflect an environmental effect of MDD in a parent.

Genetic analysis of the stress-responsive adrenocortical axis

The underlying genetic components contributing to individual variability in functions of the stress-responsive hypothalamic-pituitary-adrenal (HPA) axis are poorly understood. To determine genetic loci mediating three aspects of the adrenocortical function, we conducted a quantitative trait locus (QTL) analysis in the segregating F2 generation of a Wistar Kyoto (WKY) x Fischer 344 (F344) cross, two inbred rat strains that differ in several HPA axis measures. The following three components of adrenocortical function are known to be regulated by different mechanisms that are mediated via suprahypothalamic, hypothalamic, pituitary, and intra-adrenal influences: basal plasma corticosterone (Cort) levels, plasma Cort response to a 10-min restraint stress, and adrenal weight. Genome scans identified a complex genetic architecture for the basal Cort phenotype, including sex and maternal lineage effects. Pairwise interactions were also identified for this trait. We identified three significant and two suggestive QTLs for stress Cort, along with two pairs of interacting loci for this trait. Four highly significant and two suggestive loci were identified for adrenal weight, with no interacting loci. In contrast to basal Cort, no sex- or lineage-dependent QTL were identified for stress Cort or adrenal weight, despite the large sex differences in these phenotypes. We identified three nucleotide alterations in an obvious candidate gene mapped to the most significant QTL for stress Cort, Cort-binding globulin (CBG), one of which is known to alter CBG binding. This analysis confirms that three separate traits regulated by the HPA axis are controlled by multiple, but mainly nonoverlapping, QTLs.

Developing an Agenda for Translational Studies of Resilience and Vulnerability Following Trauma Exposure

Here we outline a translational research agenda for studies of resilience, defined as the process of adapting well in the face of adversity or trauma. We argue that an individual differences approach to the study of resilience, in which the full range of behavioral and biological responses to stress exposure is examined can be applied across human samples (e.g., people who have developed psychopathology versus those who have not; people who have been exposed to trauma versus those who have not) and even, in some cases, across species. We delineate important psychological resilience-related factors including positive affectivity and optimism, cognitive flexibility, coping, social support, emotion regulation, and mastery. Key brain regions associated with stress-related psychopathology have been identified with animal models of fear (e.g., extinction and fear conditioning; memory reconsolidation) and we describe how these regions can be studied in humans using neuroimaging technology. Finally, we cite recent research identifying neuroendocrine markers of resilience and recovery in humans (e.g., neuropeptide Y [NPY], dehydroepiandrosterone [DHEA]) that can also be measured, in some cases, in other species. That exposure to adversity or trauma does not necessarily lead to impairment and the development of psychopathology in all people is an important observation. Understanding why this is so will provide clues for the development of therapeutic interventions for those people who do develop stress-related psychopathology, or even for the prevention of adverse outcomes.

Saliva cortisol in posttraumatic stress disorder: a community epidemiologic study

BACKGROUND

Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, so it was expected that posttraumatic stress disorder (PTSD) would be associated with activation of this axis; however, studies have found both increased and decreased cortisol in PTSD. To address this question, we collected saliva cortisol at home in a subsample of a longitudinal epidemiologic sample.

METHODS

Six hundred eighty-four persons randomly selected from the total sample of 913 were requested to collect saliva samples upon awakening and in the early evening. Of these, 538 responded with samples, 516 of whom met inclusion criteria. These were 68 exposed to trauma with lifetime PTSD, 265 exposed to trauma with no PTSD, and 183 never exposed to trauma.

RESULTS

In a comparison of these three groups, lifetime PTSD revealed elevated evening saliva cortisol compared with exposed/no PTSD. When lifetime comorbidity with major depressive disorder (MDD) was included in the analysis, only persons with comorbid PTSD and MDD showed this evening elevation in cortisol. Persons with PTSD alone (never MDD) showed normal saliva cortisol levels, as did subjects with lifetime MDD alone.

CONCLUSIONS

Neither exposure to trauma nor PTSD alone is associated with alterations in saliva cortisol; however, elevated cortisol is found in PTSD comorbid with lifetime MDD.

Salivary cortisol and posttraumatic stress disorder in a low-income community sample of women

BACKGROUND

Studies of male combat veterans with posttraumatic stress disorder have demonstrated a profile of low cortisol. Studies with women with posttraumatic stress disorder (PTSD) have focused on childhood sexual abuse and holocaust survivors, both of whom experienced trauma during development, which could be different than adult trauma exposure.

METHODS

Using an epidemiologic sample of low-income women from an urban area in Michigan, we conducted structured psychiatric interviews and saliva cortisol collection on a subsample of women with exposure to trauma but never PTSD (n = 72), recent PTSD (n = 29), and past PTSD (n = 70). Saliva cortisol was collected at awakening, 30 minutes later, at bedtime, and during a clinic visit.

RESULTS

Recent trauma exposure but not past trauma exposure led to an increase in saliva cortisol. Neither recent PTSD nor past PTSD resulted in any saliva cortisol changes compared with the trauma exposed, never PTSD group. Recent major depression (past 12 months) demonstrated a weak effect (p =.08) on bedtime saliva cortisol.

CONCLUSIONS

While recent trauma exposure can increase saliva cortisol, neither recent nor past PTSD affected saliva cortisol in our community sample of women. Our data do not support saliva cortisol changes associated with PTSD.

Cortisol responses to daily events in major depressive disorder

OBJECTIVE

Abnormal responses of the hypothalamic-pituitary-adrenal (HPA) axis to stress are thought to be involved in the pathophysiology of major depressive disorder (MDD). The aim of the present study was to determine whether cortisol responses to negative and positive daily events in depressed participants (N= 47) differed from such responses in healthy participants (N= 39). We also examined the influence of clinical characteristics and possible gender differences in cortisol responses to events. Finally, the role of mood changes in mediating cortisol responses was assessed.

METHODS

Experience sampling methodology (self-reports of mood and events, with simultaneous saliva samples, 10 times each day for 6 consecutive days) and multilevel regression analysis were used to examine the relationship between events in daily life and salivary cortisol levels.

RESULTS

In contrast to healthy participants, depressed participants showed no increase in cortisol following negative events. Responses were even more blunted in depressed participants with a family history of mood disorders. Although the effects of negative events on cortisol responses appeared to be mediated by changes in mood, negative affect tended to be less closely associated with cortisol levels in depressed participants. Depressed women showed larger cortisol responses to negative events than depressed men. Positive events had no effect on cortisol levels in either group.

CONCLUSIONS

These results suggest that responses of the HPA axis to negative daily events and mood changes are blunted in MDD. Future studies will need to address whether these abnormalities disappear after clinical recovery.

Neuroendocrine and cardiovascular reactivity to stress in mid-aged and older women: long-term temporal consistency of individual differences

We report long-term temporal consistency of stress-related neuroendocrine and cardiovascular variables in mid-aged and older women who performed mental math and speech stress tasks two times approximately 1 year apart. Epinephrine, norepinephrine, ACTH, cortisol, cardiac preejection period (PEP), respiratory sinus arrhythmia, heart rate (HR), blood pressure, and respiration rate were measured at baseline, after or during stressors, and 30 min posttask. Although there were exceptions, year-to-year Spearman coefficients showed mostly moderate to high consistency (rs approximately equal to .5-.8) for baseline, stressor, and posttask values. For reactivity, HR and PEP were most consistent (rs approximately equal to .65); consistency for other variables was moderate to low (rs approximately equal to .1-.4). Means of most variables changed from year to year. Results support the use of baseline, stressor, and posttask values in longitudinal studies.

Antidepressive treatment with amitriptyline and paroxetine: effects on saliva cortisol concentrations

With regard to the course of basal human hypothalamus-pituitary-adrenal (HPA) system activity, there is a lack of data for comparing different classes of antidepressants. Ninety-four patients were included in a study comparing standardized treatment with paroxetine (PAROX) and amitriptyline (AMI) after a drug-free period of at least 6 days. Saliva for measurement of cortisol concentrations was obtained daily at 0800, 1600, and 2200 during the 6 days of drug-free washout and 35 days of active treatment. The course of HPA system activity and psychopathology, as assessed by the Hamilton Depression Scale, was compared by means of repeated-measurement analyses of variance (ANOVA-rm). Only AMI responders-not PAROX responders or nonresponders to either antidepressant-had a significant decline in saliva cortisol concentrations. In hypercortisolemically depressed patients, treatment with AMI may be preferable to PAROX in order to lower HPA system activity.

Depressive-like behavior and stress reactivity are independent traits in a Wistar Kyoto x Fisher 344 cross

Depression is a heritable disorder that is often precipitated by stress. Abnormalities of the stress-reactive hypothalamic-pituitary-adrenal (HPA) axis are also common in depressed patients. In animal models, the forced swim test (FST) is the most frequently used test of depressive-like behavior. We have used a proposed animal model of depression, the Wistar Kyoto (WKY) rat, to investigate the relationship as well as the mode of inheritance of FST behaviors and HPA measures. Through reciprocal breeding of WKY and F344 parent strains and brother-sister breeding of the F1 generation, we obtained 486 F2 animals. Parent, F1 and F2 animals were tested in the FST. Blood samples were collected for determination of basal and stress (10-min restraint) plasma corticosterone (CORT) levels, and adrenal weights were measured. We found that all measures were heritable to some extent and that this heritability was highly sex dependent. Both correlation and factor analyses of the F2 generation data demonstrate that FST behavior and HPA axis measures are not directly related. Thus, the underlying genetic components of depressive-like behavior and HPA axis abnormalities are likely to be disparate in the segregating F2 generation of a WKY x F344 cross.

Heritability of cortisol levels: review and simultaneous analysis of twin studies

Cortisol has a pivotal role in physical and mental health, but relatively few studies have paid attention to individual differences in cortisol levels and the etiology of these differences, in particular their possible genetic basis. In this article we review the existing literature on the heritability of cortisol levels. Most of the studies, which have been carried out in genetically informative samples, lack methodological consistency with regard to frequency and timing of sample collection. The circadian rhythm in cortisol levels was often not taken into account. A power analysis shows that none of these studies used adequate sample sizes to distinguish genetic from shared environmental influences as a cause for familial aggregation. Results of a simultaneous analysis of 5 comparable twin studies suggest a heritability of 62%. Hence, we conclude that, to understand the contribution of genetic and (shared) environmental influences to variation in basal cortisol levels, future studies should be designed more rigorously with strict collection and sampling protocols, sufficient sample size and repeated measures across multiple days.

Maternal stress beginning in infancy may sensitize children to later stress exposure: effects on cortisol and behavior

BACKGROUND

Preclinical studies demonstrate that the neonatal environment can permanently alter an individual's responses to stress. To demonstrate a similar phenomenon in humans, we prospectively examined the relationships of maternal stress beginning in infancy and concurrent stress on preschoolers' hypothalamic-pituitary-adrenal activity and later mental health symptoms.

METHODS

Salivary cortisol levels were assessed in 282 4.5-year-old children and 154 of their siblings. Maternal reports of stress were obtained when the children were ages 1, 4, and 12 months, and again at 4.5 years. Children's mental health symptoms were assessed in first grade.

RESULTS

A cross-sectional analysis revealed that preschoolers exposed to high levels of concurrent maternal stress had elevated cortisol levels; however, a longitudinal analysis revealed that concurrently stressed children with elevated cortisol also had a history of high maternal stress exposure in infancy. Importantly, children exposed only to high levels of concurrent or early stress had cortisol levels that did not significantly differ from those never exposed to stress. Further analysis of the components of stress indicated that maternal depression beginning in infancy was the most potent predictor of children's cortisol. We also found that preschoolers with high cortisol levels exhibited greater mental health symptoms in first grade.

CONCLUSIONS

These results link the findings of preclinical studies to humans by showing that exposure to early maternal stress may sensitize children's pituitary-adrenal responses to subsequent stress exposure.

The cortisol and glucocorticoid receptor response to low dose dexamethasone administration in aging combat veterans and holocaust survivors with and without posttraumatic stress disorder

BACKGROUND

Because alterations in cortisol negative feedback inhibition associated with aging are generally opposite of those observed in posttraumatic stress disorder (PTSD), we examined the cortisol and glucocorticoid receptor (GR) response to dexamethasone (DEX) in older trauma survivors.

METHODS

Twenty-three Holocaust survivors (9 men, 14 women), 27 combat veterans (all male), and 10 comparison subjects (7 men, 3 women) provided samples for plasma or salivary cortisol and glucocorticoid receptor determination in mononuclear leukocytes at 8:00 AM on the day of, and following, 0.5 mg of DEX at 11:00 PM.

RESULTS

Greater percent suppression of cortisol and lymphocyte GR was observed in older trauma survivors with PTSD compared to survivors without PTSD and comparison subjects. There was a significant main effect of depression in the direction of reduced suppression following DEX, consistent with the effects of DEX in major depressive disorder patients. Responses to DEX were uncorrelated with PTSD symptom severity, but cortisol suppression was associated with years elapsed since the most recent, but not focal, traumatic event.

CONCLUSIONS

The response to DEX is generally similar in older and younger trauma survivors, but the findings suggest that age, symptom severity, and lifetime trauma exposure characteristics may influence this response.