Salivary cortisol in unaffected twins discordant for affective disorder

Struggling Can Also Show on the Inside: Current Knowledge of the Impact of Childhood Maltreatment on Biomarkers in Mood Disorders

The link between childhood maltreatment and mood disorders is complex and involves multiple bio-psycho-social factors that affect multiple molecular pathways. The present narrative review aims to clarify the current understanding of the impact of childhood maltreatment on biomarkers in patients with mood disorders and their first-degree relatives. Neurotransmitters, such as serotonin, dopamine, norepinephrine, and hormones (eg the stress hormone cortisol), play a crucial role in regulating mood and emotion. Childhood maltreatment can alter and affect the levels and functioning of these neurotransmitters in the brain; further, childhood maltreatment can lead to structural and connectivity changes in the brain, hence contributing to the development of mood disorders and moderating illness presentation and modifying response to treatments. Childhood maltreatment information, therefore, appears mandatory in treatment planning and is a critical factor in therapeutic algorithms. Further research is needed to fully understand these pathways and develop new treatment modalities for individuals with mood disorders who have experienced childhood maltreatment and effective preventive interventions for individuals at risk of developing mood disorders.

Hair cortisol in newly diagnosed bipolar disorder and unaffected first-degree relatives

OBJECTIVE

Hair cortisol is a promising new biomarker of retrospective systemic cortisol concentration. In this study, we compared hair cortisol concentrations in patients with newly diagnosed bipolar disorder (BD), their unaffected first-degree relatives and healthy individuals and identified potential predictors of hair cortisol concentrations in patients with BD.

METHOD

In a cross-sectional design, we compared hair cortisol concentrations in 181 patients with newly diagnosed/first episode BD, 42 of their unaffected first-degree relatives and 101 healthy age- and sex-matched individuals with no personal or first-degree family history of affective disorder. In patients with BD, we further investigated whether medication- and illness related variables, as well as measures of stressful life events in the preceding 12 months and childhood trauma, were associated with hair cortisol concentrations.

RESULTS

Hair cortisol concentrations were 35.1% (95%CI: 13.0-61.5) higher in patients with BD (P = 0.001) compared with healthy individuals in models adjusted for age and sex. Hair cortisol concentrations in unaffected first-degree relatives did not differ from healthy individuals (P = 0.8). In patients, neither medication, illness duration nor stress related variables were associated with hair cortisol concentrations.

CONCLUSION

We found elevated hair cortisol concentrations in patients newly diagnosed with BD indicating the presence of physiological stress in early stages of BD.

Parental history of depression and higher basal salivary cortisol in unaffected child and adolescent offspring

INTRODUCTION

There are contradictory findings regarding the associations of parental depression on the hypothalamic-pituitary-adrenal axis activity of their offspring. We aimed to explore the associations of parental depression on the diurnal salivary cortisol profile in their child and adolescent offspring.

METHODS

A total of 189 unaffected child and adolescent offspring as determined by structured clinical interview were divided into 3 groups according to their parental history of depression, namely current parental depression (CPD, n = 27), past parental depression (PPD, n = 57), and no parental depression (NPD, n = 105). Diurnal saliva samples were collected to measure the cortisol awakening response and diurnal cortisol profile.

RESULTS

CPD group had significantly higher basal cortisol level (mean ± SE = 11.9 ± 0.80 nmol/dl) than PPD group (mean ± SE = 9.7 ± 0.73 nmol/dl, post hoc p = .024) and NPD group (mean ± SE = 10.2 ± 0.52 nmol/dl, post hoc p = .031) and lower cortisol level at noon, but comparable cortisol levels in other time points. The cortisol awakening response reference to increase (AUCi) were significantly blunted in CPD group when compared with PPD and NPD (post hoc p < .01). Adjustment for potential confounding factors did not change major findings. Further analyses revealed that main influences were derived from current maternal depression.

LIMITATIONS

A single day of saliva sample.

CONCLUSION

Current but not past (lifetime) parental depression is associated with higher basal salivary cortisol and blunted cortisol awakening response in their children and adolescents.

Sleep and circadian alterations in people at risk for bipolar disorder: A systematic review

BACKGROUND

Sleep and circadian abnormalities have been mostly demonstrated in bipolar patients. However, it is not clear whether these alterations are present in population at high risk for bipolar disorder (BD), indicating a possible risk factor for this condition.

OBJECTIVE

This systematic review aims to define current evidence about sleep and rhythm alterations in people at risk for BD and to evaluate sleep and circadian disorders as risk factor for BD.

METHODS

The systematic review included all articles about the topic until February 2016. Two researchers performed an electronic search of PubMed and Cochrane Library. Keywords used were 'sleep' or 'rhythm' or 'circadian' AND 'bipolar disorder' or 'mania' or 'bipolar depression' AND 'high-risk' or 'risk'.

RESULTS

Thirty articles were analyzed (7451 participants at risk for BD). Sleep disturbances are frequent in studies using both subjective measures and actigraphy. High-risk individuals reported irregularity of sleep/wake times, poor sleep and circadian rhythm disruption. Poor sleep quality, nighttime awakenings, and inadequate sleep are possible predictive factors for BD. A unique study suggested that irregular rhythms increase risk of conversion. People at risk for BD showed high cortisol levels in different times of day. Studies about anatomopathology, melatonin levels, inflammatory cytokines and oxidative stress were not identified. The most important limitations were differences in sleep and rhythm measures, heterogeneity of study designs, and lack of consistency in the definition of population at risk.

CONCLUSION

Sleep and circadian disturbances are common in people at risk for BD. However, the pathophysiology of these alterations and the impact on BD onset are still unclear.

Sleep- and circadian rhythm-associated pathways as therapeutic targets in bipolar disorder

INTRODUCTION

Disruptions in sleep and circadian rhythms are observed in individuals with bipolar disorders (BD), both during acute mood episodes and remission. Such abnormalities may relate to dysfunction of the molecular circadian clock and could offer a target for new drugs.

AREAS COVERED

This review focuses on clinical, actigraphic, biochemical and genetic biomarkers of BDs, as well as animal and cellular models, and highlights that sleep and circadian rhythm disturbances are closely linked to the susceptibility to BDs and vulnerability to mood relapses. As lithium is likely to act as a synchronizer and stabilizer of circadian rhythms, we will review pharmacogenetic studies testing circadian gene polymorphisms and prophylactic response to lithium. Interventions such as sleep deprivation, light therapy and psychological therapies may also target sleep and circadian disruptions in BDs efficiently for treatment and prevention of bipolar depression.

EXPERT OPINION

We suggest that future research should clarify the associations between sleep and circadian rhythm disturbances and alterations of the molecular clock in order to identify critical targets within the circadian pathway. The investigation of such targets using human cellular models or animal models combined with 'omics' approaches are crucial steps for new drug development.

Cortisol awakening response and subsequent depression: prospective longitudinal study

BACKGROUND

Some studies have found an association between elevated cortisol and subsequent depression, but findings are inconsistent. The cortisol awakening response may be a more stable measure of hypothalamic-pituitary-adrenal function and potentially of stress reactivity.

AIMS

To investigate whether salivary cortisol, particularly the cortisol awakening response, is associated with subsequent depression in a large population cohort.

METHOD

Young people (aged 15 years, n = 841) from the Avon Longitudinal Study of Parents and Children (ALSPAC) collected salivary cortisol at four time points for 3 school days. Logistic regression was used to calculate odds ratios for developing depression meeting ICD-10 criteria at 18 years.

RESULTS

We found no evidence for an association between salivary cortisol and subsequent depression. Odds ratios for the cortisol awakening response were 1.24 per standard deviation (95% CI 0.93-1.66, P = 0.14) before and 1.12 (95% CI 0.73-1.72, P = 0.61) after adjustment for confounding factors. There was no evidence that the other cortisol measures, including cortisol at each time point, diurnal drop and area under the curve, were associated with subsequent depression.

CONCLUSIONS

Our findings do not support the hypothesis that elevated salivary cortisol increases the short-term risk of subsequent depressive illness. The results suggest that if an association does exist, it is small and unlikely to be of clinical significance.

Serotonin transporter genotype, salivary cortisol, neuroticism and life events: impact on subsequent psychopathology in healthy twins at high and low risk for affective disorder

OBJECTIVE

To investigate if cortisol alone or in interaction with other risk factors (familial risk, the serotonin transporter genotype, neuroticism and life events (LEs)) predicts onset of psychiatric disorder in healthy individuals at heritable risk.

MATRIAL AND METHODS

In a high-risk study, 234 healthy monozygotic and dizygotic twins with or without a co-twin history of affective disorder (high and low risk twins) were baseline assessed. Participants were followed up for seven years and then reassessed with a personal interview revealing whether they had developed psychiatric illness.

RESULTS

36 participants (15.4%) developed psychiatric disorder. Using Cox proportional hazards ratio (HR) estimates neither morning nor evening salivary cortisol at baseline did predict illness onset. In multivariate Cox models, the two-way interaction between morning cortisol and LEs lifetime before baseline was significantly associated with onset. Further, the HR of onset was higher concerning individuals carrying the short allele of the 5-HTTPLR and having experienced more LEs lifetime. Familial risk for affective disorder predicted illness and the risk of onset was further increased in individuals at familial risk carrying the short allele of the 5-HTTPLR.

CONCLUSIONS

Cortisol levels alone do not increase the risk of onset of psychiatric illness but the interaction of a lower cortisol level and the experience of more LEs do. The 5-HTTLPR genotype seems to interact and contribute to increased stress vulnerability in combination with other stress indicators of illness thereby adding to the risk of subsequent psychopathology.

Cortisol at the emergency room rape visit as a predictor of PTSD and depression symptoms over time

BACKGROUND

Dysregulation of the hypothalamic-pituitary-adrenal axis, typically reflected by alterations in cortisol responsivity, has been associated with exposure to traumatic events and the development of stress-related disorders such as posttraumatic stress disorder (PTSD) and depression.

METHODS

Serum cortisol was measured at the time of a post sexual assault medical exam among a sample of 323 female victims of recent sexual assault. Analyses were conducted among 235 participants who provided data regarding history of previous assault as well as PTSD and depression symptoms during at least one of the three follow-ups.

RESULTS

Growth curve models suggested that prior history of assault and serum cortisol were positively associated with the intercept and negatively associated with the slope of PTSD and depression symptoms after controlling for covariates. Prior history of assault and serum cortisol also interacted to predict the intercept and slope of PTSD and depression symptoms such that women with a prior history of assault and lower ER cortisol had higher initial symptoms that decreased at a slower rate relative to women without a prior history and those with higher ER cortisol.

CONCLUSIONS

Prior history of assault was associated with diminished acute cortisol responsivity at the emergency room visit. Prior assault history and cortisol both independently and interactively predicted PTSD and depression symptoms at first follow-up and over the course a 6-month follow-up.

Cortisol secretion in depressed, and at-risk adults

Distinct patterns of cortisol secretion have been associated with depression in past research, but it remains unclear whether individuals at-risk for depression may also have similar patterns of cortisol secretion. This is the first study to date of both naturalistic diurnal cortisol secretion and cortisol reactivity to a psychosocial laboratory stressor in depressed and at-risk adults. Cortisol secretion patterns were compared for 57 currently depressed, at-risk (based on trait-level positive and negative affect), and control participants over 5 days and in response to a laboratory stressor. After controlling for potentially confounding biobehavioral variables, the depressed group had a larger cortisol awakening response (CAR) and higher average diurnal cortisol compared to control participants. Individuals at-risk for depression also had significantly higher waking cortisol levels than control participants. Results for the psychosocial laboratory stressor did not show the predicted elevations in cortisol for depressed and at-risk participants compared to controls. The at-risk group recovered more quickly when compared to the depressed group both in levels of cortisol and concurrent measures of negative affect. The at-risk and depressed participants were similar on the diurnal cortisol measures, but differed on response to the laboratory social stressor, suggesting divergence in cortisol secretion patterns between currently depressed and temperamentally at-risk individuals. Further investigation of HPA functioning of individuals at-risk for depression may clarify the stress processes involved in risk for depression onset.

Cortisol awakening response is linked to disease course and progression in multiple sclerosis

Objectives

Dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis has frequently been reported in multiple sclerosis (MS). So far, HPA axis function in MS has predominantly been studied under pharmacological stimulation which is associated with a series of methodological caveats. Knowledge of circadian cortisol patterns and cortisol awakening response (CAR) is still limited.

Methods

A total of 77 MS patients (55 relapsing-remitting MS (RRMS)/22 secondary-progressive MS (SPMS)) as well as 34 healthy control (HC) subjects were enrolled. Diurnal cortisol release was assessed by repeated salivary cortisol sampling. Neurological disability was rated by the Kurtzke’s Expanded Disability Status Scale (EDSS). Depressive symptoms and perceived stress were assessed by self-report measures.

Results

RRMS but not SPMS patients differed in circadian cortisol release from HC subjects. Differences in cortisol release were restricted to CAR. Treated and treatment naïve RRMS patients did not differ in CAR. In a RRMS follow-up cohort (nine months follow-up), RRMS patients with EDSS progression (≥0.5) expressed a significantly greater CAR compared to HC subjects. RRMS patients with a stable EDSS did not differ from HC subjects. Neither depressive symptoms nor perceived stress ratings were associated with CAR in RRMS patients. In a step-wise regression analysis, EDSS at baseline and CAR were predictive of EDSS at follow-up (R² = 67%) for RRMS patients.

Conclusions

Circadian cortisol release, in particular CAR, shows a course specific pattern with most pronounced release in RRMS. There is also some evidence for greater CAR in RRMS patients with EDSS progression. As a consequence, CAR might be of predictive value in terms of neurological disability in RRMS patients. The possible role of neuroendocrine-immune interactions in MS pathogenesis is further discussed.

The effect of escitalopram versus placebo on perceived stress and salivary cortisol in healthy first-degree relatives of patients with depression-A randomised trial

The effect of selective serotonin reuptake inhibitors (SSRI) on healthy individuals remains unclear. We tested the hypothesis that escitalopram decreases perceived stress and salivary cortisol. The trial has a randomised, blinded, placebo-controlled, parallel-group design. After informed consent 80 healthy first-degree relatives to patients with depression were randomly allocated to receive daily tablets of escitalopram 10mg or placebo for 4 weeks. The area under the curve (AUC) for awakening and all day salivary cortisol was analysed in samples taken immediately after awakening and at 15-min intervals for the next hour, and at 12:00, 18:00 and 23:00. The salivary cortisol awakening response, all day salivary cortisol, and scale scores on sleep, pain, aggression, quality of life, and perceived stress assessed at entry were compared to values following 4 weeks of intervention. Statistically significant decreases were found in awakening salivary cortisol (P=0.04) and in all day salivary cortisol (P=0.02) in the escitalopram group compared with the placebo group. There were no statistically significant differences in perceived stress between the intervention groups. These findings from a randomised clinical trial suggest that a long-term escitalopram administration to healthy participants results in a decrease in the hypothalamic-pituitary-adrenal (HPA) activity measured by salivary cortisol compared with inert placebo. However, change in salivary cortisol was one out of multiple outcome measures. The results of the present trial do not refute salivary cortisol as a potential endophenotype for depression.

No evidence for an anti-inflammatory effect of escitalopram intervention in healthy individuals with a family history of depression

Inflammation may contribute to the pathogenesis of depression and antidepressants are hypothesised to have an anti-inflammatory effect. In this randomised double-blinded trial we investigated the cytokine levels in supernatants of stimulated whole blood samples from first degree relatives to patients with depression randomised to a single daily dose of either 10mg escitalopram or placebo for four weeks. No significant differences were found in any of the cytokine levels between the participants treated with escitalopram (n=21) or placebo (n=23). Our data does thus not support the hypothesis of a global anti-inflammatory effect of escitalopram on cytokines in healthy subjects.

Effects of early-life adversity on white matter diffusivity changes in patients at risk for major depression

BACKGROUND

Relatives of patients with major depressive disorder (MDD) and people who experienced early-life adversity are at risk for MDD. The aim of our study was to investigate whether unaffected first-degree healthy relatives (UHRs) of patients with MDD show changes in white matter fibre connections compared with healthy controls and whether there are interactions between early-life adversity and these microstructural changes.

METHODS

Unaffected, healthy first-degree relatives of patients with MDD and healthy controls without any family history for a psychiatric disease underwent high angular resolution diffusion imaging with 61 diffusion directions. Data were analyzed with tract-based spatial statistics, and findings were confirmed with tractography.

RESULTS

Twenty-one UHRs and 24 controls participated in our study. The UHRs showed greater fractional anisotropy than controls in the body and splenium of the corpus callosum, inferior fronto-occipital fasciculus (IFO), left superior longitudinal fasciculus (SLF) and right fornix. The UHRs who experienced more early-life adversity had greater fractional anisotropy than those with less early-life adversity in the splenium of the corpus callosum, fornix, IFO and SLF; in controls, early-life adversity was found to be associated with decreased fractional anisotropy in these fibre tracts.

LIMITATIONS

Studying participants' strategies for coping with early-life adversity would have been helpful. Crossing fibres intracts are a general limitation of the method used.

CONCLUSION

Altogether, our findings provide evidence for greater fractional anisotropy in UHRs and for interaction between early-life adversity and family risk on white matter tracts involved in cognitive-emotional processes. Whether stronger neural fibre connections are associated with more resilience against depression needs to be addressed in future studies.

Circadian cortisol, depressive symptoms and neurological impairment in early multiple sclerosis

OBJECTIVE

There is evidence for the existence of a hyperactive hypothalamus-pituitary-adrenal (HPA) axis and its potential role in disease progression in multiple sclerosis (MS). Depressive symptoms are also common in MS. At the same time, depressive symptoms are often associated with an elevated circadian cortisol secretion. So far, little is known about the interplay between depressive symptoms and circadian HPA axis abnormalities in MS.

METHODS

Here we investigated depressive symptoms, circadian HPA axis function, cortisol awakening response (CAR) and neurological impairment in 32 early stage relapsing-remitting MS (RRMS) patients and 16 age- and sex-matched controls. Saliva cortisol samples were collected in patients' home environment. Depressive symptoms were assessed by self-report measures. Neurological impairment was assessed by the Kurtzke Expanded Disability Status Scale (EDSS).

RESULTS

RRMS patients expressed a significantly higher CAR when compared to healthy controls. After patients were divided into two groups based on their depressive symptom load (Beck Depression Inventory (BDI); median-split), only RRMS patients with moderately elevated depression scores (BDI high) statistically differed in their cortisol release when compared to healthy controls. RRMS patients with low depression scores (BDI low) expressed similar circadian patterns as healthy controls. Neurological impairment (EDSS) was more pronounced in the BDI high group than in the BDI low group.

CONCLUSION

In summary, there is evidence, that a hyperactive HPA axis is primarily present in MS patients expressing moderately elevated depressive symptoms. MS patients with only few depressive symptoms do not significantly differ in CAR when compared to healthy controls. To the best of our knowledge, this is the first study showing that in early stage MS, a hyperactive HPA axis is primarily present in patients who express moderate depressive symptoms.

The use of the zebrafish model in stress research

The study of the causes and mechanisms underlying psychiatric disorders requires the use of non-human models for the test of scientific hypotheses as well as for use in pre-clinical drug screening and discovery. This review argues in favor of the use of zebrafish as a novel animal model to study the impact of early (stressful) experiences on the development of differential stress phenotypes in later life. This phenomenon is evolutionary conserved among several vertebrate species and has relevance to the etiology of psychiatric disorders. Why do we need novel animal models? Although significant progress has been achieved with the use of traditional mammalian models, there are major pitfalls associated with their use that impedes progress on two major fronts: 1) uncovering of the molecular mechanisms underlying aspects of compromised (stress-exposed) brain development relevant to the etiology of psychiatric disorders, and 2) ability to develop high-throughput technology for drug discovery in the field of psychiatry. The zebrafish model helps resolve these issues. Here we present a conceptual framework for the use of zebrafish in stress research and psychiatry by addressing three specific domains of application: 1) stress research, 2) human disease mechanisms, and 3) drug discovery. We also present novel methodologies associated with the development of the zebrafish stress model and discuss how such methodologies can contribute to remove the main bottleneck in the field of drug discovery.

A transdisciplinary perspective of chronic stress in relation to psychopathology throughout life span development

The allostatic load (AL) model represents an interdisciplinary approach to comprehensively conceptualize and quantify chronic stress in relation to pathologies throughout the life cycle. This article first reviews the AL model, followed by interactions among early adversity, genetics, environmental toxins, as well as distinctions among sex, gender, and sex hormones as integral antecedents of AL. We next explore perspectives on severe mental illness, dementia, and caregiving as unique human models of AL that merit future investigations in the field of developmental psychopathology. A complimenting transdisciplinary perspective is applied throughout, whereby we argue that the AL model goes beyond traditional stress–disease theories toward the advancement of person-centered research and practice that promote not only physical health but also mental health.

Circadian biomarkers, circadian genes and bipolar disorders

Bipolar disorders are associated with circadian deregulations both during acute mood episodes and during euthymic periods, suggesting that these circadian rhythms may represent trait markers of the disease. Several arguments demonstrate that deregulations of circadian rhythms may be part of the pathophysiology of bipolar disorders. Abnormal quantitative and qualitative circadian disturbances have been repeatedly showed in bipolar patients, both during euthymic periods and acute phases, using different assessment tools such as actigraphy, polysomnography, and blood melatonin monitoring. In addition, many circadian physiological functions have been demonstrated to be altered in bipolar patients, such as secretion of hormones and other endogenous substances, core temperature, and fibroblasts activity. Furthermore, mood stabilizers efficiency could partially be explained by their impact on the regulation of the circadian rhythms. The implication of genetic vulnerability factors has long been demonstrated in bipolar disorders and several circadian genes have been tested for association in bipolar disorders. Although preliminary, interesting results have been obtained in several independent studies.

Escitalopram and neuroendocrine response in healthy first-degree relatives to depressed patients--a randomized placebo-controlled trial

INTRODUCTION

The mechanisms by which selective serotonin re-uptake inhibitors (SSRI) act in depressed patients remain unknown. The serotonergic neurotransmitter system and the hypothalamic-pituitary-adrenal (HPA) system may interact. The aim of the AGENDA trial was to investigate whether long-term intervention with SSRI versus placebo affects the cortisol response in the dexamethasone corticotropin-releasing hormone (DEX-CRH) test in healthy first-degree relatives to patients with major depressive disorder (MDD).

METHODS

Eighty healthy first-degree relatives to patients with MDD were randomized to escitalopram 10 mg versus matching placebo daily for four weeks. The primary outcome measure was the intervention difference in the change of the total area under the curve (CorAUC(total)) for plasma cortisol in the DEX-CRH test at entry to after four weeks of intervention.

RESULTS

Change in CorAUC(total) showed no statistically significant difference between the escitalopram and the placebo group, p = 0.47. There were large intra- and inter-individual differences in the results of the DEX-CRH test. There was statistically significant negative correlation between the plasma escitalopram concentration and change in CorAUC(total), rho = -0.41, p = 0.01. Post-hoc analyses showed a statistically significant interaction between age and intervention group and change in log CorAUC(total).

CONCLUSION

The present trial does not support an effect of escitalopram 10 mg daily compared with placebo on the HPA-axis in healthy first-degree relatives to patients with MDD. Increasing levels of escitalopram tended to decrease the HPA-response in the DEX-CRH test and this effect increased with age.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00386841.

Cortisol response to acute trauma and risk of posttraumatic stress disorder

This study sought to characterize the variability of the acute cortisol response following trauma and its relationship to posttraumatic stress disorder (PTSD). Forty eight participants were recruited within 24h of a traumatic accident requiring hospital admission. A saliva sample was collected at 08.00 h and 16.00 h 2 days, 1 month and 6 months after hospital admission, together with 24-h urine collection. Participants completed a dexamethasone suppression test (0.5mg DEX at 21.00 h) at each follow up, together with self-report questionnaires. The Clinician Administered PTSD Scale (CAPS) was administered at 1 and 6 months to identify PTSD. Prevalence of PTSD was 27% at 1 month and 21% at 6 months. PTSD symptoms at 6 months were negatively correlated with salivary cortisol at 08.00 h on day 2 (r=-0.36, p=0.04), but positively correlated with 16.00 h cortisols (r=0.41, p=0.03). A lower rise in cortisol at 08.00 h on day 2 was associated with an increase in risk of PTSD at both 1 month (OR=1.411 (1.017, 1.957)) and 6 months (OR=1.411 (1.066, 1.866)). At 1 month, 70% of participants with PTSD suppressed cortisol to more than 90% of pre-dex levels compared with 25% without PTSD (χ(2)=6.77, p=0.034). Urinary cortisol excretion was not different between groups at any time point. The findings support a hypothesis that sensitization of the HPA axis and enhanced suppression of cortisol following the dexamethasone suppression test are established early in the disease process.

Chronic stress, cognitive functioning and mental health

This review aims to discuss the evidence supporting the link between chronic stress, cognitive function and mental health. Over the years, the associations between these concepts have been investigated in different populations. This review summarizes the findings that have emerged from older populations as well as from populations suffering from pathological aging, namely Mild Cognitive Impairment and Alzheimer's Disease. Although older adults are an interesting population to study in terms of chronic stress, other stress-related diseases can occur throughout the lifespan. The second section covers some of these stress-related diseases that have recently received a great deal of attention, namely burnout, depression, and post-traumatic stress disorder. Given that chronic stress contributes to the development of certain pathologies by accelerating and/or exacerbating pre-existing vulnerabilities that vary from one individual to the other, the final section summarizes data obtained on potential variables contributing to the association between chronic stress and cognition.

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.

Parental history of depression or anxiety and the cortisol awakening response

BACKGROUND

It is unclear whether altered hypothalamic-pituitary-adrenal (HPA) axis regulation, which frequently accompanies depression and anxiety disorders, represents a trait rather than a state factor.

AIMS

To examine whether HPA axis dysregulation represents a biological vulnerability for these disorders, we compared cortisol levels in unaffected people with and without a parental history of depressive or anxiety disorders. We additionally examined whether possible HPA axis dysregulations resemble those observed in participants with depression or anxiety disorders.

METHOD

Data were from the Netherlands Study of Depression and Anxiety. Within the participants without a lifetime diagnoses of depression or anxiety disorders, three groups were distinguished: 180 people without parental history, 114 with self-reported parental history and 74 with CIDI-diagnosed parental history. These groups were additionally compared with people with major depressive disorder or panic disorder with agoraphobia (n = 1262). Salivary cortisol samples were obtained upon awakening, and 30, 45 and 60 min later.

RESULTS

As compared with unaffected participants without parental history, unaffected individuals with diagnosed parental history of depression or anxiety showed a significantly higher cortisol awakening curve (effect size (d) = 0.50), which was similar to that observed in the participants with depression or anxiety disorders. Unaffected people with self-reported parental history did not differ in awakening cortisol levels from unaffected people without parental history.

CONCLUSIONS

Unaffected individuals with parental history of depression or anxiety showed a higher cortisol awakening curve, similar to that of the participants with depression or anxiety disorders. This suggests that a higher cortisol awakening curve reflects a trait marker, indicating an underlying biological vulnerability for the development of depressive and anxiety disorders.

Variations in 5-HTTLPR: relation to familiar risk of affective disorder, life events, neuroticism and cortisol

BACKGROUND

Variations in the serotonin transporter gene (5-HTTLPR) and stressful life events are associated with affective disorders.

AIM

To investigate whether the distribution of the alleles of the 5-HTTLPR is associated with a genetic predisposition to affective disorder and whether these variations interact with life events in relation to depressive symptoms, neuroticism and salivary cortisol.

METHOD

In a high-risk population study, healthy monozygotic and dizygotic twins with (high-risk twins) and without (low-risk twins) a co-twin history of affective disorder were identified through nationwide registers.

RESULTS

When comparing the 81 individuals homozygote for the long allele with the 125 individuals hetero- and homozygote for the short allele no associations between the allele distribution and a genetic predisposition were found. The presence of the short allele of the 5-HTTLPR and the experience of SLE was associated with a higher neuroticism score, but not with depressive symptoms nor awakening or evening salivary cortisol.

CONCLUSION

A combination of variants in 5-HTTLPR and environmental stress seems to increase neuroticism in healthy individuals.

Deployment-related severe fatigue with depressive symptoms is associated with increased glucocorticoid binding to peripheral blood mononuclear cells

Severe fatigue and co-morbid depressive symptoms are frequently reported by recently deployed military personnel. Stress can induce lasting changes in the negative feedback regulation of the hypothalamic-pituitary-adrenal axis (HPA-axis) and the regulation of the immune system by cortisol. Since these actions of cortisol are modulated via glucocorticoid receptors (GR), we investigated the effect of deployment and of deployment-related fatigue on glucocorticoid binding to peripheral blood mononuclear cells (PBMCs) in a prospective design. Psychological assessments and blood sample collection took place before and one and six months after deployment. Participants were selected from a larger group and assigned to three groups based on their level of fatigue and depressive symptoms six months after deployment. We compared fatigued participants without depressive symptoms (n=21), fatigued participants with depressive symptoms (n=14) and non-fatigued participants without depressive symptoms (n=21). Fatigued participants with depressive symptoms at six months after deployment had higher glucocorticoid binding to PMBCs than the other two groups at all three time points. Notably, this difference was already present before deployment. There was no effect of deployment on glucocorticoid binding to PBMCs. The observed differences in glucocorticoid binding were not related to pre-existing group differences in psychological symptoms. No group differences were observed in the composition of the PBMC population and plasma cortisol levels. These results indicate that high glucocorticoid binding to PBMCs might represent a vulnerability factor for the development of severe fatigue with depressive symptoms after a sustained period of stress, such as deployment.

The BDNF Val66Met polymorphism: relation to familiar risk of affective disorder, BDNF levels and salivary cortisol

BACKGROUND

Brain-derived neurotrophic factor (BDNF) and the hypothalamic-pituitary-adrenal (HPA) axis are considered to play an important role in the pathophysiology of affective disorders. The aim of the present study was to investigate whether the BDNF Val66Met polymorphism is associated with a familiar risk of affective disorder and whether these genotypes affect whole blood BDNF level and salivary cortisol.

METHOD

In a high-risk study, healthy monozygotic and dizygotic twins with and without a co-twin (high- and low-risk twins, respectively) history of affective disorder were identified through nationwide registers.

RESULTS

Familiar predisposition to unipolar and bipolar disorder was not associated with any specific genotype pattern of the BDNF Val66Met polymorphism, not in this sample of 124 val/val, 58 val/met and 8 met/met individuals. However, the combination of having a high familiar risk of affective disorder and the met allele was associated with a higher whole blood BDNF (p=0.02) and a higher evening cortisol level (p=0.01), but not with awakening cortisol.

CONCLUSION

Individuals at high risk of affective disorders and who are carriers of the met allele of the Val66Met polymorphism may present with an enhanced stress response. The presence of a specific genotype alone may not enhance the risk of developing an affective episode. Rather, the altered stress response may be expressed only in combination with other risk variants through interactions with the environment.