Decrease in cortisol reverses human hippocampal atrophy following treatment of Cushing's disease

Effects of lamotrigine on hippocampal activation in corticosteroid-treated patients

BACKGROUND

An extensive animal literature suggests that stress or excessive corticosteroid exposure is associated with changes in hippocampal function and memory. These findings are pertinent to psychiatric disorders with elevated cortisol, Cushing's disease and the millions of patients receiving prescription corticosteroids. In animals, agents that decrease glutamate release attenuate the effects of corticosteroids on the hippocampus. Minimal data are available on preventing or reversing the effects of corticosteroids on the human hippocampus. We previously reported improvement in memory in corticosteroid-treated patients given lamotrigine. In this report, we examined the impact of lamotrigine on task-related hippocampal activation in patients taking prescription corticosteroids.

METHODS

A total of 28 outpatients taking long-term oral prednisone for medical conditions, such as renal transplant rejection, were randomized to lamotrigine or placebo for 24 weeks. Hippocampal activation in response to a visual memory task was assessed with blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI).

RESULTS

Consistent with a reduction in glutamate release, the right posterior hippocampus showed a significant decrease in task-related activation in the lamotrigine group as compared to the placebo group.

LIMITATIONS

The modest sample size and an assessment period of only 24 weeks are study limitations.

CONCLUSIONS

Between-group differences in hippocampal activation were observed. The results suggest that an agent that modulates glutamate may modify the effects of long-term corticosteroid exposure on the human hippocampus.

Stress, sex, and neural adaptation to a changing environment: mechanisms of neuronal remodeling

The adult brain is much more resilient and adaptable than previously believed, and adaptive structural plasticity involves growth and shrinkage of dendritic trees, turnover of synapses, and limited amounts of neurogenesis in the forebrain, especially the dentate gyrus of the hippocampal formation. Stress and sex hormones help to mediate adaptive structural plasticity, which has been extensively investigated in the hippocampus and to a lesser extent in the prefrontal cortex and amygdala, all brain regions that are involved in cognitive and emotional functions. Stress and sex hormones exert their effects on brain structural remodeling through both classical genomic as well as non-genomic mechanisms, and they do so in collaboration with neurotransmitters and other intra- and extracellular mediators. This review will illustrate the actions of estrogen on synapse formation in the hippocampus and the process of stress-induced remodeling of dendrites and synapses in the hippocampus, amygdala, and prefrontal cortex. The influence of early developmental epigenetic events, such as early life stress and brain sexual differentiation, is noted along with the interactions between sex hormones and the effects of stress on the brain. Because hormones influence brain structure and function and because hormone secretion is governed by the brain, applied molecular neuroscience techniques can begin to reveal the role of hormones in brain-related disorders and the treatment of these diseases. A better understanding of hormone-brain interactions should promote more flexible approaches to the treatment of psychiatric disorders, as well as their prevention through both behavioral and pharmaceutical interventions.

Neuropsychophysiological correlates of depression

The neuropsychiatric and cognitive deficits have been shown to exist in various psychiatric disorders. An attempt has been made by authors to evaluate the evidence pertaining to electrophysiological, structural and neuropsychological domains in depression. Renewal of interest in testing patients with depression on a broad range of neuropsychological tasks has revealed distinct pattern of cognitive impairment in cases with depression. The review focuses on structural and neuropsychological evidence of deficit in cases of depression.

Behavioral and neurobiological consequences of prolonged glucocorticoid exposure in rats: relevance to depression

Stress is a critical environmental trigger for the development of clinical depression, yet little is known about the specific neurobiological mechanisms by which stress influences the development of depressive symptomatology. Animal models provide an efficient way to study the etiology of human disorders such as depression, and a number of preclinical models have been developed to assess the link between stress, glucocorticoids, and depressive behavior. These mode ls typically make use of repeated exposure to physical or psychological stressors in rodents or other small laboratory animals. This review focuses primarily on a recently developed preclinical model of depression that uses exogenous administration of the stress hormone corticosterone (CORT) in rodents instead of exposure to physical or psychological stressors. Repeated CORT administration in rats or mice produces reliable behavioral and neurobiological alterations that parallel many of the core symptoms and neurobiological changes associated with human depression. This provides an opportunity to study behavior and neurobiology in the same animal, so that the neurobiological factors that underlie specific symptoms can be identified. Taken together, these findings suggest that exogenous CORT administration is a useful method for studying the relationship between stress, glucocorticoids, and depression. Further study with this model may provide important new data regarding the neurobiological bases of depression.

Basal hypothalamic pituitary adrenal axis activity and hippocampal volumes: the SMART-Medea study

BACKGROUND

It has frequently been hypothesized that high levels of glucocorticoids have deleterious effects on the hippocampus and increase risk for cognitive decline and dementia, but no large-scale studies in humans have examined the direct relation between hippocampal volumes and hypothalamic-pituitary-adrenal axis activity.

METHODS

Cross-sectional analyses within the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART)-Medea study, an ancillary study to the SMART-MR study on brain changes on magnetic resonance imaging (MRI) among patients with arterial disease. In 575 patients (mean age 62 +/- 9 years), diurnal cortisol rhythm was assessed with six saliva samples, collected at awakening; at 30, 45, and 60 min thereafter; and at 10 pm and 11 pm. A low dose of dexamethasone (.5 mg) was administered at 11 pm, and saliva was sampled the next morning at awakening. Volumetric measurements of the hippocampus were performed on a three-dimensional fast field echo T1-weighted scan with isotropic voxels.

RESULTS

Mean total relative hippocampal volume was 6.0 +/- .7 mL. Linear regression analyses, adjusted for age, sex, vascular risk factors, and global brain atrophy showed that participants with higher evening levels and higher awakening levels after dexamethasone had smaller hippocampal volumes [B per SD (4.2) increase = -.09 mL; 95% confidence interval -.15 to -.03 mL and B per SD (2.5) increase = -.07 mL; 95% confidence interval -.13 to -.01 mL, respectively]. The awakening response was not significantly associated with hippocampal volumes.

CONCLUSIONS

In this population, higher evening cortisol levels and reduced suppression after dexamethasone were associated with smaller hippocampal volumes, independent of total brain volume. The cortisol response after awakening was not associated with hippocampal volume.

Central role of the brain in stress and adaptation: links to socioeconomic status, health, and disease

The brain is the key organ of stress reactivity, coping, and recovery processes. Within the brain, a distributed neural circuitry determines what is threatening and thus stressful to the individual. Instrumental brain systems of this circuitry include the hippocampus, amygdala, and areas of the prefrontal cortex. Together, these systems regulate physiological and behavioral stress processes, which can be adaptive in the short-term and maladaptive in the long-term. Importantly, such stress processes arise from bidirectional patterns of communication between the brain and the autonomic, cardiovascular, and immune systems via neural and endocrine mechanisms underpinning cognition, experience, and behavior. In one respect, these bidirectional stress mechanisms are protective in that they promote short-term adaptation (allostasis). In another respect, however, these stress mechanisms can lead to a long-term dysregulation of allostasis in that they promote maladaptive wear-and-tear on the body and brain under chronically stressful conditions (allostatic load), compromising stress resiliency and health. This review focuses specifically on the links between stress-related processes embedded within the social environment and embodied within the brain, which is viewed as the central mediator and target of allostasis and allostatic load.

Lack of hippocampal volume differences in primary insomnia and good sleeper controls: an MRI volumetric study at 3 Tesla

BACKGROUND

A recent pilot study reported that hippocampal volume (HV) was reduced in patients with primary insomnia (PI) relative to normal sleepers. Loss of HV in PI might be due to chronic hyperarousal and/or chronic sleep debt. The aim of this study was to replicate the earlier pilot report while employing a larger sample, more rigorous screening criteria, and objective sleep data.

METHODS

This cross-sectional design included community recruits meeting DSM-IV criteria for PI (n=20, 10 males, mean age 39.3+/-8.7) or good sleeper controls (n=15, 9 males, mean age 38.8+/-5.3). All subjects were unmedicated and rigorously screened to exclude comorbid psychiatric and medical illness. PI subjects underwent overnight polysomnography to screen for sleep-related breathing and movement disorders. HV and total brain volumes were derived by MRI employing a Siemens/Trio scanner operating at 3 Tesla. Data also included 2 weeks of sleep diaries and wrist actigraphy.

RESULTS

Mean HV was 4322.0+/-299.7 mm(3) for the good sleeper controls and 4601.55+/-537.4 mm(3) for the PI group. The dependent variable, HV, was analyzed by ANCOVA. Main effects were diagnosis and gender; whole brain volume served as the covariate. Although the overall model was significant (F=6.3, p=0.001), the main effects of diagnosis (F=2.14) and gender (F=0.04) were not significant. The covariate of whole brain volume was significant (F=5.74, p=0.023) as was the interaction of diagnosis with gender (F=10.22, p=0.003), with male insomniacs having larger HVs than male controls.

CONCLUSIONS

This study did not replicate a previously published report of HV loss in primary insomnia. Differences between our finding and the previous report might be due to sample composition and method of MRI assessment. Furthermore, we demonstrated no objective differences between the controls and PIs in actigraphic measures of sleep maintenance. Within the PIs, however, actigraphic measures of poor sleep maintenance were associated with smaller HV.

Hippocampus abnormalities in at risk mental states for psychosis? A cross-sectional high resolution region of interest magnetic resonance imaging study

BACKGROUND

Hippocampal volume (HV) reduction is well documented in schizophrenia. However, it is still unclear whether this change is a pre-existing vulnerability factor, a sign of disease progression, a consequence of environmental factors, such as drug use, antipsychotic medication, or malnutrition. The timing of HV changes is not well established, but a lack of macrostructural hippocampal brain abnormalities before disease onset would rather support a neuroprogressive illness model.

AIM

To investigate the timing of HV changes in emerging psychosis.

METHODS

A cross-sectional MRI study of manually traced HVs in 37 individuals with an At Risk Mental State (ARMS) for psychosis, 23 individuals with First-Episode Psychosis (FEP), and 22 Healthy Controls (HC) was performed. We compared left and right HVs corrected for whole brain volume across groups using analysis of covariance (ANCOVA) with gender as a covariate. Sixteen of 37 ARMS individuals developed a psychotic disorder during follow up (ARMS-T). The mean duration of follow up in ARMS was 25.1months.

RESULTS

The overall ANCOVA model comparing left HVs across FEP, ARMS and HC indicated a significant general group effect (p<.05) with largest volumes in ARMS and smallest in FEP. ARMS-T subjects had significantly larger left HVs compared to FE but no HV differences compared to HC (p<0.05). Over all groups, we found an asymmetry between the left and right mean HVs and a strong effect of sex.

DISCUSSION

The present study suggests that macrostructural hippocampal abnormalities probably occur in the context of the first psychotic breakdown.

Mice overexpressing corticotropin-releasing factor show brain atrophy and motor dysfunctions

Chronic stress and persistently high glucocorticoid levels can induce brain atrophy. Corticotropin-releasing factor (CRF)-overexpressing (OE) mice are a genetic model of chronic stress with elevated brain CRF and plasma corticosterone levels and Cushing's syndrome. The brain structural alterations in the CRF-OE mice, however, are not well known. We found that adult male and female CRF-OE mice had significantly lower whole brain and cerebellum weights than their wild type (WT) littermates (347.7+/-3.6mg vs. 460.1+/-4.3mg and 36.3+/-0.8mg vs. 50.0+/-1.3mg, respectively) without sex-related difference. The epididymal/parametrial fat mass was significantly higher in CRF-OE mice. The brain weight was inversely correlated to epididymal/parametrial fat weight, but not to body weight. Computerized image analysis system in Nissl-stained brain sections of female mice showed that the anterior cingulate and sensorimotor cortexes of CRF-OE mice were significantly thinner, and the volumes of the hippocampus, hypothalamic paraventricular nucleus and amygdala were significantly reduced compared to WT, while the locus coeruleus showed a non-significant increase. Motor functions determined by beam crossing and gait analysis showed that CRF-OE mice took longer time and more steps to traverse a beam with more errors, and displayed reduced stride length compared to their WT littermates. These data show that CRF-OE mice display brain size reduction associated with alterations of motor coordination and an increase in visceral fat mass providing a novel animal model to study mechanisms involved in brain atrophy under conditions of sustained elevation of brain CRF and circulating glucocorticoid levels.

Glucocorticoids. Mood, memory, and mechanisms

Elevated circulating levels of glucocorticoids are associated with psychiatric symptoms across several different conditions. It remains unknown if this hormonal abnormality is a cause or an effect of the psychiatric conditions. For example, the hypercortisolemia observed in a subset of patients with depression may have a direct impact on the symptoms of depression, but it is also possible that the hypercortisolemia merely reflects the stress associated with depression. Further, rather than causing depression, hypercortisolemia could represent a homeostatic attempt to overcome glucocorticoid resistance. Each of these possibilities will be considered, and correlational and causal evidence will be reviewed. This article will focus on the relationships between glucocorticoids and psychiatric symptoms in Cushing's syndrome, major depression, and steroid psychosis/steroid dementia, as well as the effects of exogenously administered glucocorticoids in normal volunteers. Similarities and differences in the relationship of glucocorticoid hormones to psychiatric symptoms in these conditions will be reviewed. Possible mediators of glucocorticoid effects on the brain and behavior, as well as possible "pro-aging" effects of glucocorticoids in certain cells of the body, will be reviewed. The article concludes with a conceptual model of glucocorticoid actions in the brain that may lead to novel therapeutic opportunities.

Central nervous system effects of natural and synthetic glucocorticoids

Natural glucocorticoids (NGC) physiologically modulate body homeostasis and coordinate adaptive responses to stress, involving almost all organs and tissues, including brain. Since their therapeutic availability, synthetic GC (SGC) have been successfully prescribed for a variety of diseases. Mounting evidence, however, demonstrated pleiotropic adverse effects (AE), including central nervous system (CNS) disturbances, which are often misdiagnosed or underestimated. The aim of the present study was therefore to review and discuss the CNS effects of both NGC and SGC. A detailed search was carried out of the available literature using the PubMed (US National Library of Medicine) database. Cortisolemia plays a crucial role in control of behavior, cognition, mood, and early life programming of stress reactivity. Hypercortisolemia or SGC treatments may induce behavioral, psychic and cognitive disturbances, due to functional and, over time, structural alterations in specific brain target areas. These AE are generally dose and time dependent (infrequent at prednisone-equivalent doses <20 mg/day) and usually reversible. Pediatric patients are particularly susceptible. Behavioral changes, including feeding and sleeping modifications, are common. Psychic AE are unpredictable and heterogeneous, usually mild/moderate, severe in 5-10% of cases. Manic symptoms have been mostly associated with short SGC courses, and depressive disorder with long-term treatments. Suicidality has been reported. Cognitive AE peculiarly affect declarative memory performance. Physiologic levels of NGC are essential for efficient brain functions. Otherwise, hypercortisolemia and SGC treatments may cause dose-/time-dependent neuropsychic AE and, over time, structural alterations in brain target areas. Clinicians should carefully monitor patients, especially children and/or when administering high doses SGC.

The effects of chronic glucocorticoid exposure on dendritic length, synapse numbers and glial volume in animal models: implications for hippocampal volume reductions in depression

Glucocorticoids (GCs) are hormones secreted by the adrenal glands as an endocrine response to stress. Although the main purpose of GCs is to restore homeostasis when acutely elevated, animal studies indicate that chronic exposure to these hormones can cause damage to the hippocampus. This is indicated by reductions in hippocampal volume, and changes in neuronal morphology (i.e., decreases in dendritic length and number of dendritic branch points) and ultrastructure (e.g., smaller synapse number). Smaller hippocampal volume has been also reported in humans diagnosed with major depressive disorder or Cushing's disorder, conditions in which GCs are endogenously and chronically elevated. Although a number of studies considered neuron loss as the major factor contributing to the volume reduction, recent findings indicated that this is not the case. Instead, alterations in dendritic, synaptic and glial processes have been reported. The focus of this paper is to review the GC effects on the cell number, dendritic morphology and synapses in an effort to better understand how these changes may contribute to reductions in hippocampal volume. Taken together, the data from animal models suggest that hippocampal volumetric reductions represent volume loss in the neuropil, which, in turn, under-represent much larger losses of dendrites and synapses.

Brain development under stress: hypotheses of glucocorticoid actions revisited

One of the conundrums in today's stress research is why some individuals flourish and others perish under similar stressful conditions. It is recognized that this individual variability in adaptation to stress depends on the outcome of the interaction of genetic and cognitive/emotional inputs in which glucocorticoid hormones and receptors play a crucial role. Hence one approach towards understanding individual variation in stress coping is how glucocorticoid actions can change from protective to harmful. To address this question we focus on four hypotheses that are connected and not mutual exclusive. First, the classical Glucocorticoid Cascade Hypothesis, in which the inability to cope with chronic stress causes a vicious cycle of excess glucocorticoid and downregulation of glucocorticoid receptors (GR) in the hippocampus triggering a feed-forward cascade of degeneration and disease. Second, the Balance Hypothesis, which takes also the limbic mineralocorticoid receptors (MR) into account and proposes that an integral limbic MR:GR imbalance is causal to altered processing of information in circuits underlying fear, reward, social behaviour and resilience, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and impairment of behavioural adaptation. The MR:GR balance is altered by gene variants of these receptor complexes and experience-related factors, which can induce lasting epigenetic changes in the expression of these receptors. A particular potent epigenetic stimulus is the maternal environment which is fundamental for the Maternal Mediation Hypothesis. The outcome of perinatal gene x environment interaction, and thus of MR:GR-mediated functions depends however, on the degree of 'matching' with environmental demands in later life. The Predictive Adaptation Hypothesis therefore presents a conceptual framework to examine the role of glucocorticoids in understanding individual phenotypic differences in stress-related behaviours over the lifespan.

Chronic psychosocial stress exacerbates impairment of cognition and long-term potentiation in beta-amyloid rat model of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a degenerative disorder that leads to progressive cognitive decline. Alzheimer's disease develops as a result of over-production and aggregation of beta-amyloid (Abeta) peptides in the brain. The reason for variation in the gravity of symptoms among AD patients is unknown and might result from patient-related factors including lifestyle. Individuals suffering from chronic stress are at an increased risk for developing AD. This study investigated the effect of chronic psychosocial stress in Abeta rat model of AD.

METHODS

Psychosocial stress was induced with a rat intruder model. The rat model of AD was induced by 14-day osmotic pump infusion of a mixture of 300 pmol/day Abeta(1-40)/Abeta(1-42). The effect of chronic stress on the severity of Abeta-induced spatial learning and memory impairment was tested by three approaches: behavioral testing in the radial arm water maze, in vivo electrophysiological recording in anesthetized rat, and immunoblot analysis to determine protein levels of learning- and memory-related molecules.

RESULTS

A marked impairment of learning and memory developed when stress was combined with Abeta, more so than that caused by Abeta alone. Additionally, there was a significantly greater impairment of early-phase long-term potentiation (E-LTP) in chronically stressed/Abeta-treated rats than in either the stressed or Abeta-treated rats. This might be a manifestation of the reduction in protein levels of calcium/calmodulin-dependent protein kinase II (CaMKII) and the abnormal increase in calcineurin levels.

CONCLUSIONS

Chronic stress significantly intensified Abeta-induced deficits of short-term memory and E-LTP by a mechanism involving decreased CaMKII activation along with increased calcineurin levels.

Antiapoptotic and neurotrophic effects of antidepressants: a review of clinical and experimental studies

Recent studies have strengthened the role of the abnormalities in neurotrophic pathways in the pathophysiology of depression. It has been shown that the depletion of growth factors, particularly brain-derived neurotrophic factor, may result in depression-like behavior in animals and may induce cellular changes that are reminiscent of those observed in depressed patients. Some authors even suggested that increased neuronal cell loss may contribute to the pathogenesis of depression. Hence, appreciable interest has been focused on the trophic and antiapoptotic effects of antidepressant drugs. In this paper, we put emphasis on the contribution of hippocampal atrophy, increased cell death and alterations in trophic factors to the pathogenesis of depression and their relationship to the potential of antidepressants to reverse these changes by modulating trophic factor cascades and preventing apoptosis. First, evidences for increased hippocampal atrophy and cell death in depression are discussed, followed by a review of selected studies of special interest that concern antiapoptotic action of antidepressant drugs. Next, depression-related neurotrophic abnormalities and their reversal by antidepressants are depicted. Finally, relationships among neurotrophins, antiapoptotic proteins and antioxidant enzymes in the pathology and treatment of depression are pointed out.

Delirium and long-term cognitive impairment

Delirium is a severe, acute neuropsychiatric syndrome that is highly prevalent in acute hospital populations. Delirium has noticeable effects on length of hospitalization, cost of care, mortality and morbidity. In addition to these well-established adverse consequences, there is increasing evidence linking delirium and a higher risk of long-term cognitive impairment (LTCI), including dementia. A prior review (Jackson, Gordon, Hart, Hopkins, & Ely, 2004), in which nine studies (total N = 1,885, years 1989-2003) were considered, concluded that there was evidence for an association between delirium and LTCI. Here we provide a review of studies published since Jackson's review. We included nine reports, with a total of 2,025 patients. The studies show diverse sample sizes, methodologies, designs and patient populations. However, taken together, the results of these new studies broadly confirm that there is a link between delirium and LTCI. We go on to discuss putative mechanisms and explanations. These include (1) delirium as a marker of chronic progressive pathology, but unrelated to any progression, (2) delirium as a consequence of acute brain damage which is also responsible for a 'single hit' or triggering of active processes causing LTCI, (3) delirium itself as a cause of LTCI, and (4) drug treatment of delirium or other conditions as a cause of LTCI. We conclude with suggestions for future research.

The rebirth of neuroscience in psychosomatic medicine, Part I: historical context, methods, and relevant basic science

Neuroscience was an integral part of psychosomatic medicine at its inception in the early 20th century. Since the mid-20th century, however, psychosomatic research has largely ignored the brain. The field of neuroscience has burgeoned in recent years largely because a variety of powerful new methods have become available. Many of these methods allow for the noninvasive study of the living human brain and thus are potentially available for integration into psychosomatic medicine research at this time. In this first paper we examine various methods available for human neuroscientific investigation and discuss their relative strengths and weaknesses. We next review some basic functional neuroanatomy involving structures that are increasingly being identified as relevant for psychosomatic processes. We then discuss, and provide examples of, how the brain influences end organs through "information transfer systems," including the autonomic, neuroendocrine, and immune systems. The evidence currently available suggests that neuroscience holds great promise for advancing the goal of understanding the mechanisms by which psychosocial variables influence physical disease outcomes. An increased focus on such mechanistic research in psychosomatic medicine is needed to further its acceptance into the field of medicine.

Treatment of bipolar disorder: new perspectives

Treatment of bipolar disorder (BD) has traditionally focused on alleviation of acute symptoms and prevention of future recurrences. Current treatment guide-lines advocate more or less similar treatment algorithms for all patients. Such approach largely ignores the clinical, genetic, and pathophysiological heterogeneity of BD, which makes certain patients more (or less) likely to respond to specific treatments. Variables such as family history, comorbidity, course of illness, quality and duration of previous remissions, physical and medical comorbidity, and side-effects may help in selecting the most effective treatment for an individual patient, yet their value is not recognized by current algorithms. As well, polymorphisms of specific genes may prove useful in predicting treatment outcome and/or understanding the pharmacological mechanisms of mood stabilization. Novel molecular targets have recently emerged from studies of mechanisms of action of available mood stabilizers. They include inhibitors of protein kinase C, inhibitors of glycogen synthase kinase, or medications modulating glutamatergic neurotransmission. As well, treatment targets are moving beyond acute symptoms and prevention of mood episodes. Cognitive deficits, persistence of residual symptoms, and increased mortality of BD are recognized as important for outcome of BD, yet are not always adequately addressed by traditional treatments.

Imaging stress effects on memory: a review of neuroimaging studies

OBJECTIVE

To review and give an overview of neuroimaging studies that look at the role of stress (hormones) on memory.

METHOD

An overview will be given of imaging studies that looked at the role of stress (hormones) on memory. Stress is here defined as the acute provocation of the sympathetic adrenal medullar system and the hypothalamic-pituitary-adrenal axis in experimental designs. Stress hormone levels can be raised endogenously in response to stimulus material (for example, pictures and films) or social evaluative threat situations (stress tasks). Other studies use the exogenous application of drugs to enhance or decrease stress hormone levels. Finally, we review studies on chronic stress and memory.

RESULTS

Stress or emotional arousal, leading to increased noradrenaline or cortisol levels, led to better memory performance when it is applied during perception or encoding. Brain regions involved in this process were medial temporal lobe regions such as amygdala and hippocampus, and several parts of the prefrontal cortex (PFC). High stress levels accompanied by high cortisol levels during retrieval led to impaired memory performance. Sex effects on memory as well as lateralization effects on brain activation were found.

CONCLUSION

High stress levels during encoding and consolidation of emotional material involve increased amygdala and hippocampus activation. The role of the anterior cingulate cortex and other parts of the PFC during perception and encoding of arousing material appears to be a modulating one. However, additional research is needed to shed more light on the nature of the brain changes during stress, especially during retrieval.

Increased cortisol levels in cognitively challenging situations are beneficial in young but not older subjects

RATIONALE

Adaptation to stressful situations changes with increasing age. This is also reflected in age-related differences in effects of acute stress on, e.g., episodic memory. Less is known about age-related differences of the cognitive effects of individual stress responses to challenging situations.

OBJECTIVE

To investigate the influence of the individual cortisol response (as a marker for the individual stress level) on behavioral and neural measures during a challenging memory paradigm.

MATERIALS AND METHODS

Twenty young and 12 older subjects were scanned using functional magnetic resonance imaging during encoding and retrieval of spatial contextual information. Salivary cortisol levels were measured before and after scanning.

RESULTS

A multiple regression analysis of behavioral data showed an interaction effect of age and cortisol response on memory for the items and their spatial context during retrieval due to increased accuracy with increasing cortisol responses in young compared to old subjects. During encoding, this was reflected in a positive effect of the cortisol response on prefrontal activity in young but not in older subjects. During retrieval, there was a negative effect of the cortisol response on brain activity in the hippocampus and prefrontal regions in older but not in young subjects.

CONCLUSIONS

The data suggest an increased efficiency to encode items and their context with increasing cortisol responses in young subjects, and a decreased efficiency to retrieve information with increasing cortisol responses in older subjects. We conclude that neuroendocrine responses are differentially associated with behavioral and neural measures in cognitively challenging situations in young and older volunteers.

Cushing's syndrome: aftermath of the cure

Cushing's syndrome (CS) is a chronic and systemic disease caused by endogenous or exogenous hypercortisolism, associated with an increase of mortality rate due to the clinical consequences of glucocorticoid excess, especially cardiovascular diseases. After cure, usually obtained by the surgical removal of the tumor responsible for the disease, the normalization of cortisol secretion is not constantly followed by the recovery of the clinical complications developed during the active disease, and it is often followed by the development of novel clinical manifestations induced by the fall of cortisol levels. These evidences were mostly documented in patients with pituitary-dependent CS, after surgical resection of the pituitary tumor. Indeed, despite an improvement of the mortality rate, metabolic syndrome and the consequent cardiovascular risk have been found to partially persist after disease remission, strictly correlated to the insulin resistance. Skeletal diseases, mainly osteoporosis, improve after normalization of cortisol levels but require a long period of time or the use of specific treatment, mainly bisphosphonates, to reach the normalization of bone mass. A relevant improvement or resolution of mental disturbances has been described in patients cured from CS, although in several cases, cognitive decline persisted and psychological or psychiatric improvement was erratic, delayed, or incomplete. On the other hand, development or exacerbation of autoimmune disorders, mainly thyroid autoimmune diseases, was documented in predisposed patients with CS after disease remission. The totality of these complications persisting or occurring after successful treatment contribute to the impairment of quality of life registered in patients with CS after disease cure.

Disease-specific impairments in quality of life during long-term follow-up of patients with different pituitary adenomas

OBJECTIVE

Quality of life (QoL) is impaired in patients treated for pituitary adenomas. However, differences in age and gender distributions hamper a proper comparison of QoL. Therefore, we compared age- and gender-specific standard deviations (SD) scores (Z-scores) of QoL parameters in patients treated for pituitary adenomas.

PATIENTS AND METHODS

We determined Z-scores for health-related questionnaires [the Hospital Anxiety and Depression Scale (HADS), Multidimensional Fatigue Inventory (MFI)-20, Nottingham Health Profile (NHP), and Short Form Health Survey (SF-36)] in patients during long-term follow-up (13 +/- 8 years) after treatment for pituitary adenomas. Z-scores were calculated by comparing the data for 403 patients with acromegaly (n = 118), Cushing's disease (CD; n = 58), prolactinoma (n = 128), and nonfunctioning macroadenoma (n = 99) with a control population (n = 440) for each subscale of the questionnaires and for total QoL score.

RESULTS

All subscales of the questionnaires and the total QoL score were negatively affected in patients compared to controls. Comparing the Z-scores, patients treated for acromegaly reported more impairment in physical ability and functioning and more bodily pain compared to patients treated for nonfunctioning macroadenoma and those treated for prolactinoma. Patients with CD reported impairment in physical functioning compared to patients treated for nonfunctioning macroadenoma. Linear regression analysis, with correction for age and gender, confirmed these findings. Additionally, CD was associated with increased anxiety. Hypopituitarism negatively influenced multiple aspects of QoL.

CONCLUSION

QoL is impaired in patients during long-term follow-up after treatment of pituitary adenomas. Patients with pituitary adenomas should be informed of these persistent adverse effects of their disease on QoL to prevent inappropriate expectations with respect to the long-term results of treatment.

Pituitary volumes in relatives of bipolar patients: high-risk study

BACKGROUND

Increased, decreased, as well as unchanged pituitary volumes have been reported in bipolar disorders (BD). It is unclear, whether abnormal pituitary volumes increase vulnerability for BD (primary vulnerability marker), or are secondary to burden of illness. To address this question, we performed the first high-risk study of pituitary volumes in affected and unaffected relatives of bipolar subjects.

METHOD

High-risk participants (age range 15-30 years) were recruited from families multiply affected with BD and included 24 unaffected, 19 affected subjects with first or second degree bipolar I or II relative, matched by age and sex with 31 controls without a personal or family history of psychiatric disorders. Pituitary volumes were measured on 1.5 T 3D anatomical MRI images using standard methods.

RESULTS

We found comparable pituitary volumes among unaffected, affected relatives of bipolar patients and controls. There were no differences in pituitary volumes between male and female subjects nor was there any sex by group interaction. Analyzing 26 participants with bipolar I parent or excluding 5 medicated subjects did not change the results. There were no differences between subjects from families containing bipolar I versus families containing only bipolar II subjects.

CONCLUSIONS

The lack of abnormalities in unaffected and also affected subjects early in the course of illness in our study, as well as previous investigations of bipolar and familial unipolar children and adolescents, suggest that pituitary volume abnormalities are unlikely to be a primary risk factor for mood disorders.

Attenuation of the effects of corticosteroids on declarative memory with lamotrigine

An extensive animal literature suggests that excessive corticosteroid exposure is associated with changes in memory and the hippocampus. Agents that decrease glutamate attenuate corticosteroid effects on the hippocampus. Minimal data are available on preventing or reversing corticosteroid effects on the human hippocampus. We previously reported that open-label lamotrigine was associated with significant improvement in declarative memory in corticosteroid-treated patients. We now examine the impact of 24 weeks of randomized, placebo-controlled lamotrigine therapy on declarative memory (primary aim) and hippocampal volume (secondary aim) in 28 patients (n=16 for lamotrigine, n=12 for placebo) taking prescription corticosteroids. All participants with data from at least one postbaseline assessment (n=9 for lamotrigine, n=11 for placebo) were included in the analysis. Declarative memory was assessed with the Rey Auditory Verbal Learning Test (RAVLT) at baseline and weeks 12 and 24. Hippocampal and total brain volumes were manually traced from MRI scans obtained at baseline and week 24. On the basis of an ANCOVA analysis, total words learned on the RAVLT at exit were significantly greater in the lamotrigine group (n=8, missing data or dropouts n=8) compared to the placebo group (n=11, dropout n=1). RAVLT scores in the lamotrigine group increased from mildly impaired to average range. Hippocampal volume changes were small in both lamotrigine (n=7) and placebo (n=7) groups during the 24-week assessment period and between-group differences were not significant. Results suggest that lamotrigine may improve declarative memory in patients taking prescription corticosteroids although differential dropout rate in the two groups is a concern.

A comparison of schizophrenia outpatients treated with antipsychotics with and without metabolic syndrome: findings from the CLAMORS study

OBJECTIVE

To compare clinical, laboratory, lifestyle, and sociodemographic parameters and cardiac risk in antipsychotic-treated patients with and without metabolic syndrome (MS).

METHODS

A multicenter cross-sectional study in which 117 psychiatrists recruited antipsychotic-treated outpatients meeting DSM-IV criteria for schizophrenia, schizophreniform or schizoaffective disorder. MS was diagnosed when 3 or more of the following criteria were met: waist circumference > 102 cm (men)/> 88 cm (women); serum triglycerides > or = 150 mg/dl; HDL cholesterol < 40 mg/dl (men)/< 50 mg/dl (women); blood pressure > or = 130/85 mmHg; fasting blood glucose > or = 110 mg/dl. The 10-year cardiovascular (CV) risk was assessed by the Systematic COronary Risk Evaluation (SCORE) function (CV mortality) and the Framingham function (any-CV-event).

RESULTS

1452 evaluable patients (863 men, 60.9%), aged 40.7+/-12.2 years and with a mean duration of illness of 15.5+/-10.8 years (mean+/-SD), were included. MS was present in 24.6% [23.6% (men), 27.2% (women); p=0.130]. Overall 10-year risks were 0.9+/-1.9 (SCORE) and 7.2+/-7.6 (Framingham). Coronary heart disease (CHD) 10-year risk was higher in MS patients: 6.6% vs 2.8% showed high/very-high CV mortality risk (SCORE > or = 3%), and 44.2% vs 12.9% high/very-high CV event risk (Framingham > or = 10%) (p<0.001). MS patients also had more psychopathology (PANSS) and greater severity (CGI).

CONCLUSIONS

MS is highly prevalent in antipsychotic-treated patients and is associated with increased cardiovascular risk and psychopathology.

Effects of altered corticosteroid milieu on rat hippocampal neurochemistry and structure--an in vivo magnetic resonance spectroscopy and imaging study

Altered corticosteroid milieu induces changes in hippocampal volume, neuronal structure, neurochemistry and cognitive function in humans and rodents. This in vivo magnetic resonance spectroscopy (1H MRS) and imaging (MRI) study investigated whether long-term alterations of the corticosteroid milieu cause: (i) metabolic and/or (ii) structural changes of the rat hippocampus. Therefore, hypocortisolism was induced by adrenalectomy (ADX), normocortisolism by ADX with low-dose corticosterone replacement, and hypercortisolism by ADX and high-dose dexamethasone treatment (for 11 weeks, respectively). All groups including a control group (n=23) were studied by in vivo 1H MRS and MR volumetry. Effects of treatment on normalized hippocampal metabolites and volumes were tested for significance using one-factorial multivariate analysis of variance (MANOVA). Hypercortisolemic rats revealed significantly elevated glutamate. Hypocortisolemic rats showed significantly decreased myo-inositol ratio levels, and were associated with significantly reduced normalized hippocampal volumes. Our findings suggest chronic hypercortisolism to be associated with glutamate-mediated excitotoxicity in the absence of volumetric abnormalities. In contrast, hypocortisolism appears to be associated with neurodegenerative processes, altered astrocytic metabolism but preserved neuronal density.

Role of neuroendocrine pathways in cognitive decline during aging

The pineal and pituitary-adrenocortical secretions play an important role in adaptive responses of the organism acting as coordinating signals for both several biological rhythms and multiple neuroendocrine and metabolic functions. The more relevant neuroendocrine changes occurring with ageing affect the secretion of melatonin and of corticosteroids. These changes may be clearly appreciated by the study of their circadian rhythmicity. The circadian profile of plasma melatonin was clearly flattened in elderly subjects and even more in old individuals with dementia. Indeed, the impairment of melatonin signal occurring in aging was related either to age itself or to the cognitive performances of subjects. The biosynthetic dissociation between glucocorticoids and androgen secretion is responsible for the selective impairment of androgens, such as DHEA and DHEA-S, by comparison to cortisol. Due to the opposite effects of the two kinds of corticosteroids either in the periphery and in the CNS, the imbalance between glucocorticoids and androgens, well demonstrated by the evaluation of the cortisol/DHEA-S molar ratio, may be responsible for the occurrence in the CNS of a more neurotoxic steroidal milieu, already present in clinically healthy elderly subjects and especially in patients with dementia. The effects of that steroidal milieu are more prominent at the level of the hippocampal-limbic structure, involved both in the modulation of endocrine structures, such as the HPA axis, and in the control of cognitive, behavioral and affective functions.

Is major depressive disorder a metabolic encephalopathy?

Metabolic encephalopathy is an acute disturbance in cellular metabolism in the brain evoked by conditions of hypoxia, hypoglycaemia, oxidative stress and/or inflammation. It usually develops acutely or subacutely and is reversible if the systemic disorder is treated. If left untreated, however, metabolic encephalopathy may result in secondary structural damage to the brain. Most encephalopathies are present with neuropsychiatric symptoms, one in particular being depression. However, mood disorders are often co-morbid with cardiovascular, liver, kidney and endocrine disorders, while increasing evidence concurs that depression involves inflammatory and neurodegenerative processes. This would suggest that metabolic disturbances resembling encephalopathy may underscore the basic neuropathology of depression at a far deeper level than currently realized. Viewing depression as a form of encephalopathy, and exploiting knowledge gleaned from our understanding of the neurochemistry and treatment of metabolic encephalopathy, may assist in our understanding of the neurobiology of depression, but also in realizing new ideas in the pharmacotherapy of mood disorders.

Age-dependent reduction of amygdala volume in bipolar disorder

The amygdala is hypothesized to play a critical role in mood regulation, yet its involvement in bipolar disorder remains unclear. The aim of the present study was to compare measurements of amygdala volumes in a relatively large sample of bipolar disorder patients and healthy controls ranging in age from 18 to 49 years. Subjects comprised 54 adult patients meeting DSM-IV criteria for bipolar disorder and 41 healthy controls matched for age, sex, and education. Magnetic resonance imaging (1.5 T) was performed to obtain volumetric measurements of the amygdala using a manual region-of-interest tracing method with software that allowed simultaneous visualization of the amygdala in three orthogonal planes. The anterior head of the hippocampus was removed in the sagittal plane prior to amygdala volumetry measurement. Multiple regression analysis was computed on amygdala volume measurements as a function of diagnosis, age, sex, and cerebral volume. Bipolar patients showed an age-related reduction of amygdala volume, but controls did not. Among bipolar subjects, amygdala volume was unrelated to medication history. There were no significant hemispheric or sex interactions with the main effects. Results support a role for amygdala dysfunction in bipolar disorder which appears most robustly in older relative to younger adult patients. Differential aging effects in bipolar disorder may compromise amygdala integrity and contribute to mood dysregulation.

Glucocorticoid therapy-induced memory deficits: acute versus chronic effects

Conditions with chronically elevated glucocorticoid levels are usually associated with declarative memory deficits. Considerable evidence suggests that long-term glucocorticoid exposure may cause cognitive impairment via cumulative and long-lasting influences on hippocampal function and morphology. However, because elevated glucocorticoid levels at the time of retention testing are also known to have direct impairing effects on memory retrieval, it is possible that such acute hormonal influences on retrieval processes contribute to the memory deficits found with chronic glucocorticoid exposure. To investigate this issue, we examined memory functions and hippocampal volume in 24 patients with rheumatoid arthritis who were treated either chronically (5.3 +/- 1.0 years, mean +/- SE) with low to moderate doses of prednisone (7.5 +/- 0.8 mg, mean +/- SE) or without glucocorticoids. In both groups, delayed recall of words learned 24 h earlier was assessed under conditions of either elevated or basal glucocorticoid levels in a double-blind, placebo-controlled crossover design. Although the findings in this patient population did not provide evidence for harmful effects of a history of chronic prednisone treatment on memory performance or hippocampal volume per se, acute prednisone administration 1 h before retention testing to either the steroid or nonsteroid group impaired word recall. Thus, these findings indicate that memory deficits observed under chronically elevated glucocorticoid levels result, at least in part, from acute and reversible glucocorticoid effects on memory retrieval.

No long-term effect two years after intrauterine exposure to dexamethasone on dentate gyrus volume, neuronal proliferation and differentiation in common marmoset monkeys

Glucocorticoids are prenatally administered to promote the maturation of the lungs. They, however, can affect neuronal proliferation and differentiation. In newborn marmoset monkeys, intrauterine hyperexposure to dexamethasone (DEX) resulted in a significantly decreased proliferation rate in the hippocampal dentate gyrus without affecting neuronal differentiation. In this study, marmoset monkeys received 5 mg/kg body weight DEX either during early (days 42-48) or late (days 90-96) pregnancy. The volume of the dentate granule cell layer as well as the proliferation and neuronal differentiation in the dentate gyrus of their 2-year-old offspring were investigated. The density of proliferating cells (Ki-67), apoptotic cells (in situ tailing) and cells differentiating to neurons (double cortin, TUC-4 and calretinin) were determined immunohistochemically. Analysis of the dentate granule cell layer volume showed no significant differences between early or late DEX-exposed marmosets and untreated control animals. Similarly, proliferation and neuronal differentiation in DEX-treated animals was not significantly different in comparison with controls. In summary, the decreased proliferation rate observed in newborn marmosets after intrauterine exposure to DEX was no longer detectable in their 2-year-old siblings suggesting no long-lasting effect of prenatal hyperexposure to DEX on neuronal proliferation and differentiation in the dentate gyrus of marmoset monkeys.

The influence of stress hormones on emotional memory: relevance for psychopathology

Substantial progress within recent years has led to a better understanding of the impact of stress on emotional memory. These effects are of relevance for understanding and treating psychopathology. The present selective review describes how emotional memory is modulated through stress hormones. Acute as well as chronic effects are discussed and information from rodent models is compared to human experimental studies and clinical observations. Finally, the relevance of these findings for emotional memory disturbances in psychiatric disorders is exemplified by discussions on neuroendocrine alterations in depression, post traumatic stress disorder and phobias.

The As and Ds of stress: metabolic, morphological and behavioral consequences

Unlike responses to acute stressful events that are protective and adaptive in nature, chronic stress elicits neurochemical, neuroanatomical and cellular changes that may have deleterious consequences upon higher brain functioning. For example, while exposure to acute stress facilitates memory formation and consolidation, chronic stress or chronic exposure to stress levels of glucocorticoids impairs cognitive performance. Chronic stress or glucocorticoid exposure, as well as impairments in hypothalamic-pituitary-adrenal (HPA) axis function are proposed to participate in the etiology and progression of neurological disorders such as depressive illness, anxiety disorders and post-traumatic stress disorder (PTSD). HPA axis dysfunction, impaired stress responses and elevated basal levels of glucocorticoids are also hallmark features of experimental models of type 1 and type 2 diabetes, as well as diabetic subjects in poor glycemic control. Such results suggest that stress and glucocorticoids contribute to the neurological complications observed in diabetes patients. Interestingly, many of the hyperglycemia mediated changes in the brain are similar to those observed in depressive illness patients and in experimental models of chronic stress. Such results suggest that common mechanisms may be involved in the development of the neurological complications associated with Anxiety, Depressive illness and Diabetes: the As and Ds of stress. The aim of the current review will be to discuss the mechanisms through which limbic structures such as the hippocampus and amygdala respond and adapt to the deleterious consequences of chronic stress and hyperglycemia.

Pre-training administration of tianeptine, but not propranolol, protects hippocampus-dependent memory from being impaired by predator stress

Extensive research has shown that the antidepressant tianeptine blocks the adverse effects of chronic stress on hippocampal functioning. The current series of experiments extended this area of investigation by examining the influence of tianeptine on acute stress-induced impairments of spatial (hippocampus-dependent) memory. Tianeptine (10 mg/kg, ip) administered to adult male rats before, but not after, water maze training blocked the amnestic effects of predator stress (occurring between training and retrieval) on memory. The protective effects of tianeptine on memory occurred in rats which had extensive pre-stress training, as well as in rats which had only a single day of training. Tianeptine blocked stress effects on memory without altering the stress-induced increase in corticosterone levels. Propranolol, a beta-adrenergic receptor antagonist (5 and 10 mg/kg, ip), in contrast, did not block stress-induced amnesia. These findings indicate that treatment with tianeptine, unlike propanolol, provides an effective means with which to block the adverse effects of stress on cognitive functions of the hippocampus.

Chronic low dose corticosterone exposure decreased hippocampal cell proliferation, volume and induced anxiety and depression like behaviours in mice

A dysregulated hypothalamic-pituitary-adrenal axis (HPA) has been implicated in major depressive disorder and most commonly used animal models of depression have been shown to elevate circulating levels of plasma corticosterone. We have compared the effects of chronic and acute corticosterone administration on hippocampal cell proliferation (as measured by BrdU immunohistochemistry), hippocampal volume and the appearance of anxiety (light dark box) and depression (forced swim test) like behaviours in CD1 mice. We have also examined the effects of chronic administration of fluoxetine and imipramine on these parameters. Chronic (14 days) but not acute treatment with corticosterone resulted in reduced hippocampal cell proliferation and granule cell layer volume, these changes were prevented by co-administration of imipramine and fluoxetine. In contrast, acute and 7 day but not 14 or 21 day treatment with corticosterone gave rise to a "depressed" phenotype in the forced swim test. Mice treated for 14 days with corticosterone also developed an anxious phenotype in the light dark box but only upon repeated testing. The results presented here demonstrate that moderately elevated corticosterone for a prolonged period is sufficient to induce cellular changes in the hippocampus that are prevented by chronic administration of antidepressants.

Chronic stress-induced hippocampal vulnerability: the glucocorticoid vulnerability hypothesis

The hippocampus, a limbic structure important in learning and memory, is particularly sensitive to chronic stress and to glucocorticoids. While glucocorticoids are essential for an effective stress response, their oversecretion was originally hypothesized to contribute to age-related hippocampal degeneration. However, conflicting findings were reported on whether prolonged exposure to elevated glucocorticoids endangered the hippocampus and whether the primate hippocampus even responded to glucocorticoids as the rodent hippocampus did. This review discusses the seemingly inconsistent findings about the effects of elevated and prolonged glucocorticoids on hippocampal health and proposes that a chronic stress history, which includes repeated elevation of glucocorticoids, may make the hippocampus vulnerable to potential injury. Studies are described to show that chronic stress or prolonged exposure to glucocorticoids can compromise the hippocampus by producing dendritic retraction, a reversible form of plasticity that includes dendritic restructuring without irreversible cell death. Conditions that produce dendritic retraction are hypothesized to make the hippocampus vulnerable to neurotoxic or metabolic challenges. Of particular interest is the finding that the hippocampus can recover from dendritic retraction without any noticeable cell loss. When conditions surrounding dendritic retraction are present, the potential for harm is increased because dendritic retraction may persist for weeks, months or even years, thereby broadening the window of time during which the hippocampus is vulnerable to harm, called the 'glucocorticoid vulnerability hypothesis'. The relevance of these findings is discussed with regard to conditions exhibiting parallels in hippocampal plasticity, including Cushing's disease, major depressive disorder (MDD), and post-traumatic stress disorder (PTSD).

Brain atrophy and cognitive deficits in Cushing's disease

Cushing's disease is associated with brain atrophy and cognitive deficits. Excess glucocorticoids cause retraction and simplification of dendrites in the hippocampus, and this morphological change probably accounts for the hippocampal volume loss. Mechanisms by which glucocorticoids affect the brain include decreased neurogenesis and synthesis of neurotrophic factors, impaired glucose utilization, and increased actions of excitatory amino acids. In this review, the timing, pathology, and pathophysiology of the brain atrophy in Cushing's disease are discussed. The correlation of atrophy with cognitive deficits and its reversibility is also reviewed.

A possible role for the endocannabinoid system in the neurobiology of depression

The present review synthetically describes the currently advanced hypotheses for a neurobiological basis of depression, ranging from the classical monoaminergic to the more recent neurotrophic hypothesis. Moreover, the Authors review the available preclinical and clinical evidence suggesting a possible role for the endocannabinoid system in the physiopathology of depression. Indeed, in spite of the reporting of conflicting results, the pharmacological enhancement of endocannabinoid activity at the CB1 cannabinoid receptor level appears to exert an antidepressant-like effect in some animal models of depression. On the contrary, a reduced activity of the endogenous cannabinoid system seems to be associated with the animal model of depression, namely the chronic mild stress model. Moreover, a few studies have reported an interaction of antidepressants with the endocannabinoid system. With regard to clinical studies, several authors have reported an alteration of endocannabinoid serum levels in depression, while post mortem studies have demonstrated increased levels of endocannabinoids associated to a concomitant hyperactivity of CB1 receptor in the prefrontal cortex of suicide victims. No clinical trials carried out using cannabinoids in the treatment of affective disorders have been published to date, although anecdotal reports have described both antidepressant and antimanic properties of cannabis as well as the ability of cannabis to induce mania that has also been documented. These findings are discussed, leading us to conclude that, although data available are sufficient to suggest a possible involvement of the endogenous cannabinoid system in the neurobiology of depression, additional studies should be performed in order to better elucidate the role of this system in the physiopathology of depression.

Preliminary evidence that hippocampal volumes in monkeys predict stress levels of adrenocorticotropic hormone

BACKGROUND

Hippocampal volumes previously determined in monkeys by magnetic resonance imaging are used to test the hypothesis that small hippocampi predict increased stress levels of adrenocorticotropic hormone (ACTH).

METHODS

Plasma ACTH levels were measured after restraint stress in 19 male monkeys pretreated with saline or hydrocortisone. Monkeys were then randomized to an undisturbed control condition or intermittent social separations followed by new pair formations. After 17 months of exposure to the intermittent social manipulations, restraint stress tests were repeated to determine test/retest correlations.

RESULTS

Individual differences in postrestraint stress ACTH levels over the 17-month test/retest interval were remarkably consistent for the saline (r(s) = .82, p = .0004) and hydrocortisone (r(s) = .78, p = .001) pretreatments. Social manipulations did not affect postrestraint stress ACTH levels, but monkeys with smaller hippocampal volumes responded to restraint after saline pretreatment with greater increases in ACTH levels with total brain volume variation controlled as a statistical covariate (beta = -.58, p = .031). Monkeys with smaller hippocampal volumes also responded with diminished sensitivity to glucocorticoid feedback determined by greater postrestraint ACTH levels after pretreatment with hydrocortisone (beta = -.68, p = .010).

CONCLUSIONS

These findings support clinical reports that small hippocampi may be a risk factor for impaired regulation of the hypothalamic-pituitary-adrenal axis in humans with stress-related psychiatric disorders.

Innovative approaches for the treatment of depression: targeting the HPA axis

Altered activity of the hypothalamic pituitary adrenal (HPA) axis is one of the most commonly observed neuroendocrine abnormalities in patients suffering from major depressive disorder (MDD). Altered cortisol secretion can be found in as many as 80% of depressed patients. This observation has led to intensive clinical and preclinical research aiming to better understand the molecular mechanisms which underlie the alteration of the HPA axis responsiveness in depressive illness. Dysfunctional glucocorticoid receptor (GR) mediated negative feedback regulation of cortisol levels and changes in arginine vasopressin (AVP)/vasopressin V1b receptor and corticotrophin-releasing factor/CRF1 receptor regulation of adrenocotricotrophin (ACTH) release have all been implicated in over-activity of the HPA axis. Agents that intervene with the mechanisms involved in (dys)regulation of cortisol synthesis and release are under investigation as possible therapeutic agents. The current status of some of these approaches is described in this review.

Impact of levetiracetam on mood and cognition during prednisone therapy

PURPOSE

Corticosteroid excess is associated with impairment in declarative memory and hippocampal changes. In animals, phenytoin blocks the effects of stress on memory and hippocampal histology. Levetiracetam also shows neuroprotective properties in some animal models. This report examines whether levetiracetam prevents mood or cognitive changes secondary to prescription corticosteroids.

MATERIALS AND METHODS

Thirty outpatients given systemic corticosteroid therapy for asthma were randomized to either levetiracetam (1500 mg/day) or placebo given concurrently with the corticosteroids. Mood was assessed with the Hamilton rating scale for depression (HRSD), Young mania rating scale (YMRS) and activation (ACT) subscale of the internal state scale, declarative memory with the Rey auditory verbal learning test (RAVLT), and attention and executive functioning with the Stroop color and word test at baseline and after approximately 7 days of corticosteroid plus levetiracetam or placebo therapy.

RESULTS

Levetiracetam and placebo groups showed significant improvement from baseline to exit on RAVLT total words recalled with a non-significant change on other outcomes. No significant between-group differences were found. Initial prednisone dose showed a significant correlation with change in some cognitive domains.

CONCLUSIONS

Levetiracetam was well tolerated when combined with prednisone. Significant between-group differences in mood and cognition were not found.

Improvement in mood and ideation associated with increase in right caudate volume

BACKGROUND

The basal ganglia, particularly caudate, are hypothesized to play a role in affective and obsessive-compulsive disorders. The depressive syndrome is a feature of untreated Cushing's disease. The objective of this study was to test the hypothesis that after treatment of Cushing's disease reduces elevated cortisol, improvement in mood and related ideations are associated with increase in caudate volume.

METHODS

In this longitudinal, interventional study of 23 patients with Cushing's disease, 24-hour urinary free cortisol, structural magnetic resonance imaging and behavioral measures were obtained prior to treatment and approximately one year after pituitary microadenomectomy. Five SCL-90-R subscales measuring change in mood, related ideations and physical symptoms were utilized.

RESULTS

Partial correlations (adjusted for age and time since surgery) showed change in caudate, but not hippocampal, volume was significantly associated with change in behavioral SCL-90-R subscales, indicating selectivity for structure. Right but not left caudate showed associations, suggesting selectivity for lateralization. Right caudate volume increase was significantly associated with decreases in Depression, Anxiety, Obsessive-Compulsive, and Paranoid scores, but not with Somatization (physical symptoms), indicating specificity for behavioral but not physical variables.

LIMITATIONS

A limitation is that relatively low-resolution scans were utilized. Although most likely not diminishing the significant findings, less sensitive methodology could lead to an increased probability of a type 2 error.

CONCLUSIONS

These findings support the concept that caudate, and likely right caudate, participates in human brain circuitry regulating mood.

What causes the hippocampal volume decrease in depression? Are neurogenesis, glial changes and apoptosis implicated?

Even though in vivo imaging studies document significant reductions of hippocampal volume in depressed patients, the exact underlying cellular mechanisms are unclear. Since stressful life events are associated with an increased risk of developing depression, preclinical studies in which animals are exposed to chronic stress have been used to understand the hippocampal shrinkage in depressed patients. Based on morphometrical studies in these models, parameters like dendritic retraction, suppressed adult neurogenesis and neuronal death, all due to elevated levels of glucocorticoids, have been suggested as major causative factors in hippocampal shrinkage. However, histopathological studies examining hippocampi of depressed individuals have so far failed to confirm either a massive neuronal loss or a suppression of dentate neurogenesis, an event that is notably very rare in adult or elderly humans. In fact, many of the structural changes and the volume reduction appear to be reversible. Clearly, more histopathological studies are needed; especially ones that (a) employ stereological quantification, (b) focus on specific cellular elements and populations, and (c) are performed in nonmedicated depressed patients. We conclude that mainly other factors, like alterations in the somatodendritic, axonal, and synaptic components and putative glial changes are most likely to explain the hippocampal shrinkage in depression, while shifts in fluid balance or changes in the extracellular space cannot be excluded either.

Cortisol levels in relation to hippocampal sub-regions in subjects with first episode schizophrenia

The etiology of hippocampal volumetric reductions in schizophrenia is largely unknown. In addition to genetic factors, environmental factors might also play a role. High levels of glucocorticoids are known to affect hippocampal volume in disorders such as Cushing's syndrome, but the relationship between cortisol and hippocampal volumes has not been studied in schizophrenia. We obtained diurnal salivary cortisol levels and MRI images to explore the link between cortisol levels and regional hippocampal volumes in healthy controls (N=29) and subjects with first episode schizophrenia (N=16) at the time of first admission. T1-weighted coronal MR images (slice thickness=1.5 mm) were acquired through the whole head using a 3D Fast SPGR IR Prep sequence on a 1.5 T GE imaging system. Using ANOVA, cumulative daily cortisol exposure calculated as area under the curve for each subject revealed significantly higher cortisol levels in the patient group [F(1,43)=4.4 p=0.04]. However, there were no statistically significant associations between the cortisol measures and regional hippocampal volumes in the subjects, except a trend level link between anterior hippocampal volume and cortisol in the positive direction, in parallel to previous findings in healthy adolescents. Our findings do not suggest a robust association between cortisol levels and hippocampal volumes in a first episode schizophrenia sample. Larger scale studies are needed to conclude a link between the two measures, yet it is possible that the negative association that was previously shown in other disorders may not apply to schizophrenia.

Intrapair differences in hippocampal volume in monozygotic twins discordant for the risk for anxiety and depression

BACKGROUND

Current biological psychiatric models assume that genetic and environmental risk factors for anxiety and depression act on the same brain structures.

METHODS

To test this assumption, we assessed brain anatomy by using optimized voxel-based morphometry on magnetic resonance images obtained in monozygotic twin pairs who were discordant for the risk of anxiety and depression (n = 10 pairs) and in monozygotic twin pairs who were concordant for high (n = 7 pairs) or low (n = 15 pairs) risk for anxiety and depression.

RESULTS

We observed volume reductions in the temporal lobe, most notably in the left posterior hippocampal region in subjects at high risk for anxiety and depression, but exclusively in the intrapair comparison of discordant monozygotic twins. Because monozygotic twins are genetically identical, any discordance in their risk for anxiety and depression and hippocampal volume must arise from differential exposure to environmental influences. A group comparison between pairs concordant for low or high risk, which is more likely to reflect differences in genetic vulnerability, did not show reduced temporal-lobe and posterior hippocampal volumes in the pairs at high risk for anxiety and depression.

CONCLUSIONS

This pattern of results suggests that damage to temporal-lobe structures may be specific to an environmentally driven etiology of anxiety and depression.