Marita Pruessner

Self-reported depressive symptoms and stress levels in healthy young men: associations with the cortisol response to awakening.

Objective There is evidence that clinical depression and negative mood are associated with elevated basal cortisol levels. Recently, measuring the cortisol response during the first hour in the morning with strict reference to the time of awakening was established as a reliable marker of individual adrenocortical activity. In studies using this marker, a relationship with self-reported stress levels and psychosomatic symptoms has been found. The goal of the present study was to investigate the association of self-reported depressive symptomatology with early morning free cortisol levels and their relationship to measures of stress. Methods We assessed the severity of depressive symptoms using the Hamilton Depression Inventory and chronic and acute stress perception in 40 healthy young men. Once a week, for 4 consecutive weeks, subjects provided saliva samples collected at 0, 30, and 60 minutes after awakening. Results Higher levels of depressive symptomatology were associated with a greater cortisol response after awakening. This association seemed to be stronger when only subjects in the nonclinical range of depression were included. Furthermore, cortisol levels and depressive symptomatology were significantly positively correlated with measures of chronic and acute stress perception. Conclusions The present study extends earlier findings of hypothalamus-pituitary-adrenal axis hyperactivity in clinical depression to healthy young men with mild levels of depressive symptomatology. Measuring the cortisol response to awakening is proposed as an economical alternative to traditional approaches for determining basal hypothalamus-pituitary-adrenal axis activity. Associations between depressive symptomatology and chronic stress, as well as implications for future studies, are discussed.

Deactivation of the Limbic System During Acute Psychosocial Stress: Evidence from Positron Emission Tomography and Functional Magnetic Resonance Imaging Studies

BACKGROUND Stress-induced metabolic changes can have detrimental health effects. Newly developed paradigms to investigate stress in neuroimaging environments allow the assessment of brain activation changes in association with the perception of and the metabolic response to stress. METHODS We exposed human subjects to a psychosocial stressor in one positron emission tomography (n = 10) and one functional magnetic resonance imaging (fMRI; n = 40) experiment. RESULTS We observed a profound deactivation of limbic system components including hippocampus, hypothalamus, medio-orbitofrontal cortex and anterior cingulate cortex in subjects who reacted to the stressor with a significant increase of the endocrine stress marker cortisol. Further, in the fMRI study, the degree of deactivation in the hippocampus was correlated with the release of cortisol in response to the stress task. CONCLUSIONS The observed deactivation of limbic system structures suggests elevated activation at rest and during nonstressful situations. A model is proposed where the observed reduction in limbic system activity is essential for the initiation of the stress response.

Age and Gender Predict Volume Decline in the Anterior and Posterior Hippocampus in Early Adulthood

Magnetic Resonance Imaging (MRI) provides a noninvasive method for investigating brain morphology. Within the medial temporal lobe, special attention has been paid to the hippocampus (HC) and amygdala (AG) because of their role in memory, depression, emotion, and learning. Volume changes in these areas have been observed in conjunction with certain disease states, e.g. Alzheimers disease, post-traumatic stress disorder, and depression. Aging has also been shown to result in gray matter volume loss of the overall brain, including the HC. With regard to gender specificity, results suggest a larger shrinkage for men of brain gray matter, with controversial observations being made for the HC. With recently refined MRI acquisition and segmentation protocols, the HC and AG of 80 subjects in early adulthood (39 men and 41 women, age 18–42 years) were investigated. Whereas the volume of the AG appeared to be independent of age and gender, a significant negative correlation with age for both left and right HC was found in men (r = −0.47 and −0.44, respectively) but not in women (r = 0.01 and 0.02, respectively). The volume decline in men appeared to be linear, starting at the beginning of the third life decade and approximating 1.5% per annum. Using voxel-based regressional analysis, it was shown that changes with age occurred mostly in the head and tail of the HC. This finding underscores the need to include sociodemographic variables in functional and anatomical MRI designs.

Stress regulation in the central nervous system: evidence from structural and functional neuroimaging studies in human populations - 2008 Curt Richter Award Winner

The metabolic effects of stress are known to have significant health effects in both humans and animals. Most of these effects are mediated by the major stress hormonal axis in the body, the hypothalamic-pituitary-adrenal (HPA) axis. Within the central nervous system (CNS), the hippocampus, the amygdala and the prefrontal cortex as part of the limbic system are believed to play important roles in the regulation of the HPA axis. With the advent of structural and functional neuroimaging techniques, the role of different CNS structures in the regulation of the HPA axis can be investigated more directly. In the current paper, we summarize the findings obtained in our laboratory in the context of stress and HPA axis regulation. Our laboratory has developed and contributed to the development of manual and automated segmentation protocols from structural magnetic resonance imaging (MRI) scans for assessment of hippocampus, amygdala, medial temporal lobe and frontal lobe structures. Employing these protocols, we could show significant age-related changes in HC volumes, which were different between men and women, with pre-menopausal women showing smaller age-related volume decline compared to men. We could recently extent these findings by showing how estrogen therapy after menopause leads to higher volumes in the HC. Investigating possible neurotoxicity effects of steroids, we showed effects of long-term steroid exposure on HC volumes, and investigated variability of HC volumes in relation to HPA axis regulation in young and elderly populations. Here, we were able to follow-up from non-imaging studies showing that subjects low in self-esteem have higher cortisol stress responses, and the HC emerged as the critical link between these variables. Recently, we have made two more important discoveries with regard to HC volume: we could show that HC volume is as variable in young as it is in older adults, in subjects ranging in age from 18 to 80 years. Also, we have linked birth weight and maternal care to HC volumes in young adults, demonstrating the effects of variations in maternal care on the integrity of the CNS. Besides structural assessments, there is increasing interest in functional techniques to investigate possible links between CNS activity and HPA axis regulation. These two approaches complement each other; some aspects of HPA axis regulation might be linked to the integrity of a specific CNS structure, while other aspects might be linked to the function of a specific structure with no involvement of CNS morphology. Thus, we have developed a mental arithmetic stress task that can be employed in functional neuroimaging studies, and have used it in a number of functional neuroimaging studies. Employing positron emission tomography (PET), we were able to demonstrate that stress causes dopamine release if subjects reported low maternal care early in life. Finally, employing the task in functional magnetic resonance imaging (fMRI), we could show how exposure to stress and activation of the HPA axis are associated with decreased activity in major portions of the limbic system, a result that allows to speculate on the effects of stress on cognitive and emotional regulation in the brain. Taken together, the use of neuroimaging techniques in Psychoneuroendocrinology opens exciting new possibilities for the investigation of stress effects in the central nervous system.

Hippocampal volume is as variable in young as in older adults: implications for the notion of hippocampal atrophy in humans.

Previous studies in humans have shown the presence of an age-related reduction of hippocampal (HC) volume, as well as the presence of reduced HC volume in psychiatric populations suffering from schizophrenia, depression or post-traumatic stress disorder. Altogether, these data suggested that aging or psychiatric disease can have neurotoxic effects on the hippocampus, and lead to HC atrophy. However, these two sets of findings imply that HC volume in young healthy adults should present less variability than HC volume in older adults and psychiatric populations. In the present study, we assessed HC volume in 177 healthy men and women aged from 18 to 85 years of age. We show that the dispersion around the mean of HC volume is not different in young and older adults, so that 25% of young healthy adults present HC volume as small as the average participants aged 60 to 75 years. This shows that HC volume is as variable in young as in older adults and suggests that smaller HC volume attributed to the aging process in previous studies could in fact represent HC volume determined early in life. We also report that within similar age groups, the percentage of difference in HC volume between the individuals with the smallest HC volume (smallest quartile) and the group average is greater than the percentage of difference reported to exist between psychiatric populations and normal control in recent meta-analyses. Taken together, these results confront the notion of hippocampal atrophy in humans and raise the possibility that pre-determined inter-individual differences in HC volume in humans may determine the vulnerability for age-related cognitive impairments or psychopathology throughout the lifetime.

Stress and protective factors in individuals at ultra-high risk for psychosis, first episode psychosis and healthy controls

Stress-vulnerability models of schizophrenia regard psychosocial stress as an important factor in the onset and aggravation of psychotic symptoms, but such research in the early phases of psychosis is limited. Protective factors against the effects of stress might be the key to understanding some inconclusive findings and to the development of optimal psychosocial interventions. The present study compared self-reported levels of stress, self-esteem, social support and active coping in 32 patients with a first episode of psychosis (FEP), 30 individuals at ultra-high risk for psychosis (UHR) and 30 healthy controls. Associations with symptoms of psychosis were assessed in both patient groups. Individuals at UHR reported significantly higher stress levels compared to FEP patients. Both patient groups showed lower self-esteem compared to controls, and the UHR group reported lower social support and active coping than controls. These group differences could not be explained by age and dose of antipsychotic medication in the FEP group. In the UHR group, higher stress levels and lower self-esteem were associated with more severe positive and depressive symptoms on the Brief Psychiatric Rating Scale. Multiple regression analyses revealed that stress was the only significant predictor for both symptom measures and that the relationship was not moderated by self-esteem. Our findings show that individuals at UHR for psychosis experience high levels of psychosocial stress and marked deficits in protective factors. The results suggest that psychosocial interventions targeted at reducing stress levels and improving resilience in this population may be beneficial in improving outcomes.

Blunted cortisol awakening response in men with first episode psychosis: Relationship to parental bonding

Early life adversity has been associated with an increased risk for the development of mental health problems, including psychotic disorders, perhaps mediated by a changed regulation of the Hypothalamic Pituitary Adrenal (HPA) axis. Aim of the present study was to confirm our previous finding of an attenuated cortisol awakening response (CAR) in men with first episode psychosis (FEP) and to explore a possible link between a blunted CAR and early adversity as indicated by perceived parental bonding. Fifty-eight patients (38 men, 20 women; mean age 23.25±3.86) with a FEP and 33 healthy community controls (16 men, 17 women; mean age 22.91±3.64) participated in the study. Saliva samples for assessment of the CAR were collected immediately, 30 and 60min after awakening. Complete cortisol samples were available in a reduced sample of 56 patients (37 men) and 30 controls (13 men). Parental bonding during the first 16 years of life was assessed retrospectively with the Parental Bonding Inventory. Results showed a significantly blunted CAR in male compared to female patients, confirming our previously reported findings. We also found a lower CAR in the total FEP group compared to controls, which failed to reach significance after controlling for time of awakening. A significantly lower percentage of patients than controls reported optimal maternal parenting. Within the patient group, significantly fewer male than female patients reported optimal maternal and paternal parenting. Only in patients, unfavorable paternal parenting was related to a blunted CAR. Dysregulation of the HPA axis in male patients might be a consequence of non-optimal parenting and contribute to the less favorable course of psychosis in men compared to women.

Sex differences in the cortisol response to awakening in recent onset psychosis

A dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis has been suggested as a factor in the etiology and exacerbation of psychosis, but has not been reported consistently. Sex differences are apparent in many aspects of psychotic disorders and may explain some of the equivocation associated with the regulation of the HPA axis in the illness. The present study compared the cortisol response to awakening (CRA) in 27 patients (16 men and 11 women) with recent onset of psychosis (within the past 2 years) and 40 age and gender matched controls. Within the patient group, we also assessed the relationship between the CRA and positive and negative symptoms of psychosis, anxiety and depression. The CRA in patients was not significantly different from controls. However, within the patient group, we observed a significant sex difference, with a blunted cortisol response to awakening in men but not in women (F=7.26; p<0.002). This difference could not be explained by differences between male and female patients in awakening time, medication, or diagnosis of schizophrenia vs. affective psychosis. Cortisol levels were not related to symptom measures. Our findings demonstrate a dysregulation of the HPA axis in male patients with recent onset of psychosis. This sex specificity might be related to and explain in part the unfavorable course of the illness observed in men.

The neural diathesis-stress model of schizophrenia revisited: An update on recent findings considering illness stage and neurobiological and methodological complexities

HighlightsDistinct patterns of HPA axis dysregulation in psychosis are observed for basal, stress‐induced and awakening cortisolHPA axis alterations in clinical high risk populations resemble those observed in established psychosis, but are less consistentConfounding factors and challenges in the measurement of stress, cortisol, and symptomatic outcome affect interpretation of resultsGenetic, epigenetic, neurodevelopmental and environmental factors may modulate the effects of HPA axis abnormalities on psychosis progressionHPA axis activity in psychosis appears to be associated with altered neurotransmitter activity, inflammatory processes and brain structure &NA; Over the past decade, our understanding of the role of stress in serious mental illness has become more sophisticated. In this paper, we revisit the neural diathesis‐stress model of schizophrenia that was initially proposed in 1997 and updated in 2008. In light of cumulative research findings, we must now encompass evidence on the premorbid periods of psychosis, and our more nuanced understanding of hypothalamic‐pituitary‐adrenal (HPA) axis function and its association with neurodevelopmental, epigenetic, neurotransmitter, and inflammatory processes, as well as brain structure and function. Giving consideration to the methodological complexities that have become more apparent as research in this area has burgeoned, the various indices of HPA axis function, and the different stages of illness, we review relevant research published since the 2008 update of the model. We conclude by proposing an extended neural diathesis‐stress model that addresses the broader neurobiological context of stress psychobiology in psychosis progression. Implications of this model for best practice, with regards to both future research and treatment strategies, are discussed.

Hippocampal activation during a cognitive task is associated with subsequent neuroendocrine and cognitive responses to psychological stress

Increased activation of the hypothalamus pituitary adrenal (HPA) axis, marked by increased secretion of cortisol, is a biological marker of psychological stress. It is well established that the hippocampus plays an important role in the regulation of HPA axis activity. The relationship between cortisol (stress‐related elevation or exogenous administration) and the hippocampal‐related cognitive function is often examined. However, few human studies to date have examined the effect of stress on hippocampal activity and the interactions between stress‐induced activation of the HPA axis and hippocampal function during different phases of cognitive function. On the basis of our previous work, we hypothesized that group differences in stress‐sensitivity relate to differences in hippocampal‐related stress‐integration. To test this hypothesis, we conducted a functional MRI study using tasks known to involve the hippocampal formation: novel‐picture encoding, psychological stress, and paired‐picture recognition. On the basis of their cortisol responses to stress, we divided subjects into stress‐responders (increase in cortisol, n = 9) and nonresponders (decrease in cortisol, n = 10). Responders showed higher hippocampal deactivation during the stress task and lower recognition scores due to a larger number of misses. Intriguingly, stress‐responders showed significant differences in hippocampal activation already prior to stress, with higher levels of hippocampal activity during the picture encoding. Although effects of both cortisol and hippocampal activation on recognition were present in responders, similar effects were absent in the nonresponder group. Our results indicate that hippocampus plays an important role in adaptive behavioral responses. We hypothesize that states of hippocampal activation prior to stress might reflect states of vigilance or anxiety, which might be important for determining interindividual differences in subsequent stress response and cognitive performance.