Effects of early adverse experiences on brain structure and function: clinical implications

Annual Research Review: All mothers are not created equal: neural and psychobiological perspectives on mothering and the importance of individual differences

Quality of mothering relies on the integrity of multiple physiological and behavioral systems and on two maternal factors, one proximal and one distal, that have a great impact on how a mother mothers: postpartum depression and early experiences. To mother appropriately requires the action of systems that regulate sensation, perception, affect, reward, executive function, motor output and learning. When a mother is at risk to engage in less than optimal mothering, such as when she is depressed or has experienced adversity in childhood, the function of many or all of maternal and related systems may be affected. In this paper, we will review what is currently known about the biological basis of mothering, with attention to literature on hormones but with a particular focus on recent advances in the fields of functional neuroimaging. Instead of discussing strictly 'maternal' brain imaging studies, we instead use a systems approach to survey important findings relevant to brain systems integral to and/or strongly related to the mothering experience: (a) social behavior; (b) reward and affect; (c) executive function; and (d) maternal behavior. We find that there are many commonalities in terms of the brain regions identified across these systems and, as we would expect, all are sensitive to the influence of, or function differently in the context of, depression and adverse early experience. It is likely that the similarity and cross-talk between maternal, affect and stress systems, observed behaviorally, hormonally and in the context of brain function, allows for mood disturbance and early adverse experiences to have a significant impact on the quality of mothering and the motivation to mother.

Early life exposure to violence and substance misuse in adulthood-The first Brazilian national survey

BACKGROUND

Substance misuse has been a major source of health and social problems in developing societies as it has been elsewhere. There is a growing body of evidence from developed nations linking early exposure to violence in childhood with substance misuse in adulthood. The role of depression on this association is not clear. This study estimates the association between early life exposure to violence, alcohol disorders and illegal substance use in adulthood and the role of depression on these associations using a national Brazilian sample.

METHODS

The first Brazilian National Alcohol Survey gathered information on early exposure to violence and use of psychoactive substances in 1880 participants aged 20 to 60 years old selected at random from the Brazilian household population. We used weighted logistic regression to calculate adjusted odds ratios for the associations between early exposure to violence and substance misuse. To assess the mediating effect of depression on these associations we used the Sobel-Goodman Mediation Test.

RESULTS

Witnessing violence during childhood or adolescence was reported by nearly 20% of the participants whilst over 8% reported having been victims of at least one form of violence. There was a statistically significant association between early exposure to violence and alcohol abuse and/or dependence and use of illegal substances in adulthood with a dose-response relationship. Depression partially explained the association between early exposure to violence with alcohol dependence (18.77% p<0.001) and did not have a statistically significant mediating effect on the association with illegal substance use (5.83% p=0.220).

CONCLUSIONS

Adverse early life events may affect individual's susceptibility to substance misuse which can be partially mediated by depression. Prevalence of substance misuse in adulthood may be in part attributed to the prevalence of adverse childhood experience. While prevention is the ideal goal, detection and intervention with children exposed to violence must be prioritised.

Early-life stress and cognitive outcome

RATIONALE

Early-life stress is associated with later neuropsychiatric illness. While the association between early-life stress and brain development is well recognized, relatively few studies have examined the association between exposure to early-life stress and cognitive outcome.

OBJECTIVES

The objective of this paper is to examine the association between early-life stress and cognitive outcome in animal models and humans.

METHODS

In this article, we review alterations in cognitive function associated with early-life stress in animals and then discuss the association of early-life stress and cognitive function in humans.

RESULTS

Findings suggest that early-life stress is associated with abnormal cognitive function in animals and humans. Furthermore, cognitive deficits associated with exposure to early-life stress in humans may persist into at least early adulthood, although animal models of enriched environments and studies of children adopted from institutionalized care into foster families suggest that certain social factors may at least partially reverse cognitive deficits following exposure to early-life stress.

CONCLUSIONS

Exposure to stress in early life may be associated with later deficits in cognitive function.

Epigenetic marking of the BDNF gene by early-life adverse experiences

Studies over the past half-century have made it clear that environmental influences in development, particularly stress and traumatic experiences, can remain pervasive across the lifespan. Though it has been hypothesized for some time that the long-term consequences of early-life adversity represent epigenetic influences, it has not been until recently that studies have begun to provide empirical support of experience-driven epigenetic modifications to the genome. Here we focus on this theme, and review current knowledge pertaining to the epigenetics of behavioral development. At the center of our discussion is the brain-derived neurotrophic factor (BDNF) gene, as abnormal BDNF gene activity is a leading etiological hypothesis by which early-life adverse experiences persistently modify brain and behavioral plasticity.

Early life stress paradigms in rodents: potential animal models of depression?

RATIONALE

While human depressive illness is indeed uniquely human, many of its symptoms may be modeled in rodents. Based on human etiology, the assumption has been made that depression-like behavior in rats and mice can be modulated by some of the powerful early life programming effects that are known to occur after manipulations in the first weeks of life.

OBJECTIVE

Here we review the evidence that is available in literature for early life manipulation as risk factors for the development of depression-like symptoms such as anhedonia, passive coping strategies, and neuroendocrine changes. Early life paradigms that were evaluated include early handling, separation, and deprivation protocols, as well as enriched and impoverished environments. We have also included a small number of stress-related pharmacological models.

RESULTS

We find that for most early life paradigms per se, the actual validity for depression is limited. A number of models have not been tested with respect to classical depression-like behaviors, while in many cases, the outcome of such experiments is variable and depends on strain and additional factors.

CONCLUSION

Because programming effects confer vulnerability rather than disease, a number of paradigms hold promise for usefulness in depression research, in combination with the proper genetic background and adult life challenges.

Neurobiological and psychiatric consequences of child abuse and neglect

The effects of early-life trauma and its consequences for the treatment of depression are reviewed. The prevalence and clinical sequelae of early sexual and physical abuse, neglect and parental loss are described. An overview of preclinical studies that help guide clinical research and practice is presented. Human clinical studies on the neurobiological consequences of early trauma are summarized. Moderating factors, such as genetic variation and sex differences, are discussed. The few current treatment outcome studies relevant to this research area are described. Guidance for the management of patients with depression and a history of child abuse and neglect are provided. Most patients who have experienced early traumatic experiences are likely best treated with a combination of psychotherapy and pharmacotherapy. This review is dedicated to the memory of Seymour Levine who pioneered the field of early experience research and to a considerable extent inspired the clinical studies described in this review.

Interaction of childhood stress with hippocampus and prefrontal cortex volume reduction in major depression

Early emotional stress is associated with a life-long burden of risk for later depression and stressful life events contribute to the development of depressive episodes. In this study we investigated whether childhood stress is associated with structural brain alterations in patients with major depression (MD). Forty-three patients with MD and 44 age as well as gender matched healthy control subjects were investigated using high-resolution magnetic resonance imaging (MRI). Region of interest analysis of the hippocampus, whole brain voxel-based morphometry (VBM) and assessment of childhood stress was carried out. Significantly smaller hippocampal white matter and prefrontal gray matter volume was observed in patients with MD compared to healthy controls. In particular left hippocampal white matter was smaller in patients, who had emotional childhood neglect, compared to those without neglect. For male patients this effect was seen in the left and right hippocampus. Moreover, physical neglect during childhood affected prefrontal gray matter volume in healthy subjects. Both emotional neglect and brain structural abnormalities predicted cumulative illness duration and there was a significant interaction between emotional neglect and prefrontal volumes as well as hippocampal white matter on the illness course. Childhood neglect resulted in hippocampal white matter changes in patients with major depression, pronounced at the left side and in males. Most interestingly, childhood stress and brain structure volumes independently predicted cumulative illness course. Subjects with both, structural brain changes and childhood emotional neglect seem to be at a very high risk to develop a more severe illness course.

Functional emergence of the hippocampus in context fear learning in infant rats

The hippocampus is a part of the limbic system and is important for the formation of associative memories, such as acquiring information about the context (e.g., the place where an experience occurred) during emotional learning (e.g., fear conditioning). Here, we assess whether the hippocampus is responsible for pups' newly emerging context learning. In all experiments, postnatal day (PN) 21 and PN24 rat pups received 10 pairings of odor-0.5 mA shock or control unpaired odor-shock, odor only, or shock only. Some pups were used for context, cue or odor avoidance tests, while the remaining pups were used for c-Fos immunohistochemistry to assess hippocampal activity during acquisition. Our results show that cue and odor avoidance learning were similar at both ages, while contextual fear learning and learning-associated hippocampal (CA1, CA3, and dentate gyrus) activity (c-Fos) only occurred in PN24 paired pups. To assess a causal relationship between the hippocampus and context conditioning, we infused muscimol into the hippocampus, which blocked acquisition of context fear learning in the PN24 pups. Muscimol or vehicle infusions did not affect cue learning or aversion to the odor at PN21 or PN24. The results suggest that the newly emerging contextual learning exhibited by PN24 pups is supported by the 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.

Early life stressors and genetic influences on the development of bipolar disorder: the roles of childhood abuse and brain-derived neurotrophic factor

OBJECTIVES

Although there is increasing research exploring the psychosocial influences and biological underpinnings of bipolar disorder, relatively few studies have specifically examined the interplay between these factors in the development of this illness. Social-biological models within a developmental psychopathology perspective are necessary to advance our understanding of the processes involved in the onset and course of bipolar disorder. This article presents a review of the empirical literature linking childhood abuse to bipolar disorder, the research to date on the possible role of brain-derived neurotrophic factor (BDNF) in the development of this disorder, followed by a discussion of how childhood abuse may interact with BDNF.

METHODS

A literature search was conducted using Psycinfo to identify relevant articles on childhood abuse, BDNF, and bipolar disorder.

RESULTS

The extant research implicates both childhood abuse and BDNF in the etiology of bipolar disorder. Specifically, there is growing evidence associating early abuse to the development of bipolar disorder. Similarly, the BDNF Val66 allele has been linked with increased susceptibility to bipolar disorder. Based on existing research, a genetic diathesis-transactional stress model is proposed incorporating childhood abuse and the BDNF gene in the pathogenesis of bipolar disorder.

CONCLUSIONS

Although there is some support for this model, the relatively modest amount of relevant literature highlights the need for further research. An integrative theoretical framework including both social and biological processes in bipolar disorder is important for the development of effective prevention and treatment strategies for this disorder.

5HTT genotype moderates the influence of early institutional deprivation on emotional problems in adolescence: evidence from the English and Romanian Adoptee (ERA) study

BACKGROUND

A common polymorphism in the serotonin transporter gene (SLC6A4, 5HTT) has been repeatedly shown to moderate the influence of childhood adversity and stressful life events on the development of psychopathology. Using data from the English and Romanian Adoptee Study, a prospective-longitudinal study of individuals (n = 125) exposed to severe early institutional deprivation (ID), we tested whether the effect of ID on adolescent emotional problems is moderated by 5HTT genotype and stressful life events in adolescence.

METHODS

Emotional problems were assessed using questionnaire data (age 11), and on the basis of the CAPA diagnostic interview (age 15). Additionally, the number of stressful life events was measured.

RESULTS

There was a significant effect for genotype (p = .003) and a gene x environment interaction (p = .008) that was independent of age at testing. Carriers of the s/l and s/s genotype who experienced severe ID showed the highest emotional problem scores, while l/l homozygotes in the severe ID group showed the lowest overall levels. Furthermore, s/s carriers in the severe ID group who experienced a high number of stressful life events between 11 and 15 years had the largest increases in emotional problem scores, while a low number of stressful life events was associated with the largest decrease (4-way interaction: p = .05).

CONCLUSIONS

The effects of severe early ID on emotional problems in adolescence are moderated by 5HTT genotype, and influenced by stressful life events in adolescence.

Developing a neurobehavioral animal model of infant attachment to an abusive caregiver

BACKGROUND

Both abused and well cared for infants show attachment to their caregivers, although the quality of that attachment differs. Moreover, the infant's attachment to the abusive caregiver is associated with compromised mental health, especially under stress. In an attempt to better understand how abuse by the caregiver can compromise mental health, we explore the neural basis of attachment in both typical and abusive environments using infant rats, which form attachments to the mother through learning her odor. Here, we hypothesize that the neural circuitry for infant attachment differs based on the quality of the attachment, which can be uncovered during stressful situations.

METHODS

We used infant rats to compare infant attachment social behaviors and supporting neurobiology using natural maternal odor, as well as two odor-learning attachment paradigms: odor-stroke (mimics typical attachment) and odor-.5 mA shock conditioning (mimics abusive attachment). Next, to uncover differences in behavior and brain, these pups were injected with systemic corticosterone. Finally, pups were reared with an abusive mother to determine ecological relevance.

RESULTS

Our results suggest that the natural and learned attachment odors indistinguishably control social behavior in infancy (approach to the odor and interactions with the mother). However, with corticosterone injection, pups with an abusive attachment show disrupted infant social behavior with the mother and engagement of the amygdala.

CONCLUSIONS

This animal model of attachment accommodates both abusive and typical attachment and suggests that pups' social behavior and underlying neural circuitry may provide clues to understanding attachment in children with various conditions of care.

Palatable cafeteria diet ameliorates anxiety and depression-like symptoms following an adverse early environment

Early trauma contributes to psychosocial disorders later in life. An adverse early environment induced by maternal separation (MS) is known to alter behavioural and stress responses in rats. Palatable food dampens stress responses. We investigated the influence of palatable cafeteria high-fat diet (HFD) on behavioural responses following MS or non-handling (NH), versus 15min brief separation. After littering, Sprague-Dawley rats were exposed to short separation, S15 (15min), prolonged separation, S180 (180min) daily from postnatal days 2 to 14 or were non-handled. Pups were assigned to HFD or chow at weaning. We assessed depression and anxiety-like behaviour with sucrose preference test (SPT) and elevated plus maze (EPM) respectively, and measured hypothalamic CRH and hippocampal glucocorticoid receptor (GR) expression. S180 rats showed increased anxiety-and depression-like behaviours, with increased plasma corticosterone, hypothalamic CRH, and reduced hippocampal GR expression versus S15 rats. Similar effects were observed across gender. These were normalized by provision of HFD, with greater beneficial effects in males. S15 showed no benefit of HFD. NH female rats had less adverse impacts; HFD had beneficial impact on behaviour in NH males. Thus behavioural deficits and gene expression changes induced by early life stress were ameliorated by HFD. These results highlight the important place of palatable food in reducing central stress responses supporting the therapeutic value of 'comfort food'.

Prenatal alcohol exposure: fetal programming and later life vulnerability to stress, depression and anxiety disorders

Children with fetal alcohol spectrum disorder (FASD) exhibit cognitive, neuropsychological and behavioral problems, and numerous secondary disabilities including depression and anxiety disorders. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is common in depression/anxiety, reflected primarily in increased HPA tone or activity. Prenatal alcohol exposure (PAE) increases HPA tone and results in HPA dysregulation throughout life, paralleling many of the HPA changes in depression/anxiety. We review data demonstrating altered HPA function and increased depression/anxiety in FASD. In the context of the stress-diathesis model, we discuss the hypothesis that fetal programming of the HPA axis by PAE alters neuroadaptive mechanisms that mediate the stress response, thus sensitizing the organism to stressors encountered later in life, and mediating, at least partly, the increased vulnerability to depression/anxiety disorders. Furthermore, we present evidence demonstrating sex-specific alterations in both hormonal and behavioral responsiveness to tasks measuring depressive- and anxiety-like behaviors in PAE offspring. Overall, the research suggests that the stress-diathesis model provides a powerful approach for elucidating mechanisms underlying the increased vulnerability to mental illness among individuals with FASD, and developing appropriate treatments for these individuals. Dr. Seymour Levine's seminal work on the long-term consequences of early life experiences formed a framework for the development of the research described in this review.

Neonatal rearing conditions distinctly shape locus coeruleus neuronal activity, dendritic arborization, and sensitivity to corticotrophin-releasing factor

Early life events influence vulnerability to psychiatric illness. This has been modelled in rats and it has been demonstrated that different durations of maternal separation shape adult endocrine and behavioural stress reactivity. One system through which maternal separation may act is the locus coeruleus (LC)-norepinephrine system that regulates emotional arousal. Here we demonstrate that different durations of maternal separation have distinct effects on LC physiology and dendritic morphology. Rat pups were separated from the dam for 15 min/d (HMS-15) or 180 min/d (HMS-180) from post-natal days 2-14. Others were either undisturbed (HMS-0) or were vendor-purchased controls. LC characteristics were compared at age 22-35 d using whole-cell recordings in vitro. Cells were filled with biocytin for morphological analysis. LC neurons of HMS-180 rats were tonically activated compared to HMS-15 and control rats, with firing rates that were 2-fold higher than these groups. Corticotrophin-releasing factor (CRF) application did not further activate LC neurons of HMS-180 rats but increased LC firing rate in HMS-0 and control rats. LC neurons of HMS-15 rats were resistant to excitation by CRF. Maternal separation also affected LC dendritic morphology. LC dendrites of HMS-15 rats exhibited less branching and decreased total dendritic length, an effect that could decrease the probability of contacting limbic afferents that terminate in the pericoerulear region. This effect may provide a structural basis for an attenuated magnitude of emotional arousal. Together, these results demonstrate long-term consequences of early life events on the LC-norepinephrine system that may shape adult behaviour.

Transitions in sensitive period attachment learning in infancy: the role of corticosterone

Survival of altricial infants, including humans and rats, depends on attachment to the caregiver - a process that requires infants to recognize, learn, and remember their attachment figure. The demands of a dynamic environment combined with a maturing organism require frequent neurobehavioral reorganization. This restructuring of behavior and its supporting neural circuitry can be viewed through the unique lens of attachment learning in rats in which preference learning is enhanced and aversion learning is attenuated. Behavioral restructuring is well adapted to securing the crucial infant-caregiver relationship regardless of the quality of care. With maturation and the end of the infant-caregiver attachment learning period, the complex interplay of neural structures, hormones, and social behavior coordinates the developing rat's eventual transition to life outside of the nest. Nevertheless, early-life environmental and physiological stressors can alter the resilient nature of this system, particularly with respect to the amygdala, and these changes may provide important clues to understanding the lasting effects of early stress.

The response to postnatal stress: amino acids transporters and PKC activity

It is well known that animals exposed to stressful stimuli during their early life develop different neurological disorders when they become adults. In this study, we evaluated the effect of acute cold stress on gamma-aminobutyric acid (GABA) and L-Serine (L-Ser) transporters in vitro, using the uptake of [(3)H]-GABA and [(3)H]L-Ser by synaptosomes-enriched fractions isolated from rat cerebral cortex during postnatal development. GABA and L-Ser uptake studies in vitro will be used in this investigation as a colateral evidence of changes in the expression of transporters of GABA and L-Ser. We observed that the maximum velocity (V (max)) in L-Ser and GABA uptake after stress session increased in all stages studied. In contrast, K (m) values of L-Ser uptake enhancent in almost age calculated, excluding at PD21 after cold stress during development, at the same time as K (m) (uptake affinity) values of GABA increased in just about age considered but not at PD5 compared with the control group. Finally we investigated the mechanism by which cells regulate the substrate affinity of L-Ser and GABA transporters. We demonstrated a significantly increase in total PKC activity to PD5 from PD21. Pretreatment with PKC inhibitor: staurosporine (SP) led to a restoration of control uptake in several postnatal-days suggesting a relationship between amino acids system and PKC activation. These findings suggest that a single exposure to postnatal cold stress at different periods after birth modifies both GABA and L-Ser transporters and the related increase in total PKC activity could be intracellular events that participate in neuronal plasticity by early life stress, which could be relevant to function of transporters in the adult rat brain.

A preliminary study of medial temporal lobe function in youths with a history of caregiver deprivation and emotional neglect

Previous research findings have linked caregiver deprivation and emotional neglect with sensitivity to threatening cues. The present preliminary study investigated whether dysfunctions of the medial temporal lobe could underlie these associations. Using fMRI, we measured medial temporal lobe responses to emotional faces (angry, fearful, happy, neutral) among 30 youths. Eleven of the youths had a history of caregiver deprivation and emotional neglect. Attention states (i.e., attention to anger, fear, or physical attributes, or passive viewing) were systematically manipulated. Relative to comparison youths, youths with a history of caregiver deprivation and emotional neglect showed significantly greater left amygdala and left anterior hippocampus activation during the processing of threatening information. To our knowledge, these findings are the first to demonstrate altered medial temporal lobe function during the processing of threat cues in youths with a history of caregiver deprivation and emotional neglect.

Early life stress as an influence on limbic epilepsy: an hypothesis whose time has come?

The pathogenesis of mesial temporal lobe epilepsy (MTLE), the most prevalent form of refractory focal epilepsy in adults, is thought to begin in early life, even though seizures may not commence until adolescence or adulthood. Amongst the range of early life factors implicated in MTLE causation (febrile seizures, traumatic brain injury, etc.), stress may be one important contributor. Early life stress is an a priori agent deserving study because of the large amount of neuroscientific data showing enduring effects on structure and function in hippocampus and amygdala, the key structures involved in MTLE. An emerging body of evidence directly tests hypotheses concerning early life stress and limbic epilepsy: early life stressors, such as maternal separation, have been shown to aggravate epileptogenesis in both status epilepticus and kindling models of limbic epilepsy. In addition to elucidating its influence on limbic epileptogenesis itself, the study of early life stress has the potential to shed light on the psychiatric disorder that accompanies MTLE. For many years, psychiatric comorbidity was viewed as an effect of epilepsy, mediated psychologically and/or neurobiologically. An alternative – or complementary – perspective is that of shared causation. Early life stress, implicated in the pathogenesis of several psychiatric disorders, may be one such causal factor. This paper aims to critically review the body of experimental evidence linking early life stress and epilepsy; to discuss the direct studies examining early life stress effects in current models of limbic seizures/epilepsy; and to suggest priorities for future research.

Neonatal stress modulates sickness behavior

The quality of the early environment, especially during the neonatal period, influences the development of individual differences in resistance to stress and illness in adulthood. A previous study demonstrated that neonatal stress augmented proinflammatory cytokine expression and viral replication in influenza virus-infected adult mice. The goal of the following study was to examine the lifelong effects of neonatal stress on the behavioral response to an immune challenge. Neonatal stress consisted of separating mouse pups from their dams (maternal separation, MSP) at critical points of their development. In the first study, pups were separated from the dam daily for 6h between postnatal day 1 and 14. As adults, these mice were infected with influenza A/PR8 virus. In a second study, a similar paradigm of MSP was employed, and as adults mice were injected with lipopolysaccharide (LPS) (ip). In a third study pups were separated from the dam for 24h on postnatal day 4 or 9. As adults, these mice received ip injections of LPS. In all three studies, changes in body weight, food and sweet solution consumption were examined following immune challenge. As previously described, activation of the immune system using influenza virus infection or LPS administration resulted in sickness behavior that consisted of body weight loss, anorexia and reduced consumption of a sweet solution. Furthermore, neonatal stress induced more rapid kinetics of sickness behavior and augmented several aspects of these symptoms. Together with previous studies, these findings suggest that neonatal stress disrupted the regulation of innate resistance to an immune challenge resulting in enhanced immunological and behavioral responses to immune activation. Thus, long lasting effects of early stress events may be the basis for individual differences in health and susceptibility to disease.

The role of childhood abuse in HPA-axis reactivity in Social Anxiety Disorder: a pilot study

BACKGROUND

Studies on depression have found that childhood abuse (CA) is associated with a persistent sensitization of the hypothalamic-pituitary-adrenal (HPA)-axis to stress in adulthood. So far, it is unknown whether this HPA-axis sensitization is specific to depression, or whether this is a more general outcome associated with CA in patients with mood and anxiety disorders. The aim of this study was to investigate whether CA is associated with enhanced cortisol reactivity to psychosocial stress in Social Anxiety Disorder (SAD).

METHODS

Salivary cortisol levels before, during, and after exposure to psychosocial stress (i.e., Trier Social Stress Task, TSST) in SAD patients with a history of childhood abuse (SAD+CA, n=9) were compared to cortisol levels in SAD patients without a history of childhood abuse (SAD-CA, n=9), patients with PTSD related to childhood abuse (n=16), and healthy controls without a history of childhood abuse (n=16).

RESULTS

Analyses showed that the SAD+CA group had a strongly increased cortisol reactivity (mean peak: 17.5+/-1.9 nmol/l) compared to SAD-CA (mean peak: 9.0+/-1.1 nmol/l), PTSD (mean peak: 9.0+/-1.1 nmol/l) and healthy controls (mean peak: 9.6+/-1.4 nmol/l), whereas baseline cortisol levels did not differ. The enhanced increase in the SAD+CA group was not explained by stronger anxiety in response to the TSST.

CONCLUSIONS

Consistent with the findings in depression, these results show for the first time that childhood abuse is also associated with strongly increased cortisol reactivity in SAD. When replicated in a larger sample, these findings may have important implications for the treatment of SAD.

Abnormal fronto-striatal connectivity in children with histories of early deprivation: A diffusion tensor imaging study

An Inattentive/Overactive (I/O) behavioral phenotype has been reported in a significant percentage of children raised from birth in orphanages. While a number of studies have identified both functional and structural brain abnormalities in children raised from birth in orphanages, no published studies have evaluated potential neural correlates of the I/O phenotype. We applied diffusion tensor imaging (DTI) to 15 pre-teen children raised in orphanages in Eastern Europe or Asia and later adopted to the US. Fiber tracts were constructed from DTI data using probabilistic fiber tracking and the cortical fiber distribution of fibers originating from the head of the caudate was compared between the early deprivation (ED) group and 12 age-matched controls. The ED group showed a more diffuse connectivity pattern, especially in the right hemisphere, potentially related to incomplete neuronal pruning during development. These structural abnormalities may be associated with inattention and overactivity encountered in children with ED.

Amygdala, hippocampal and corpus callosum size following severe early institutional deprivation: the English and Romanian Adoptees study pilot

The adoption into the UK of children who have been reared in severely deprived conditions provides an opportunity to study possible association between very early negative experiences and subsequent brain development. This cross-sectional study was a pilot for a planned larger study quantifying the effects of early deprivation on later brain structure. We used magnetic resonance imaging (MRI) to measure the sizes of three key brain regions hypothesized to be sensitive to early adverse experiences. Our sample was a group of adoptee adolescents (N = 14) who had experienced severe early institutional deprivation in Romania and a group of non-institutionalised controls (N = 11). The total grey and white matter volumes were significantly smaller in the institutionalised group compared with a group of non-deprived, non-adopted UK controls. After correcting for difference in brain volume, the institutionalised group had greater amygdala volumes, especially on the right, but no differences were observed in hippocampal volume or corpus callosum mid-sagittal area. The left amygdala volume was also related to the time spent in institutions, with those experiencing longer periods of deprivation having a smaller left amygdala volume. These pilot findings highlight the need for future studies to confirm the sensitivity of the amygdala to early deprivation.

Altered water diffusivity in cortical association tracts in children with early deprivation identified with Tract-Based Spatial Statistics (TBSS)

Institutional rearing is associated with neurocognitive and behavioral difficulties. Although such difficulties are thought to reflect abnormal neurologic development resulting from early social deprivation (ED) and there is evidence for functional abnormality in children with histories of ED, the impact of early deprivation on brain anatomy has received little study in humans. The present study utilized an objective and sensitive neuroimaging analysis technique (Tract-Based Spatial Statistics) to evaluate white matter fractional anisotropy (FA) and diffusivity in a group of right-handed children with histories of ED (n = 17; mean age = 10.9 + 2.6 years) as compared with age-matched healthy controls (n = 15; mean age = 11.7 + or - 2.8 years). Participants underwent magnetic resonance imaging diffusion tensor imaging sequences and comprehensive neuropsychological evaluations. Results revealed reduced FA in frontal, temporal, and parietal white matter including components of uncinate and superior longitudinal fasciculi, in children with histories of ED, providing further support for limbic and paralimbic abnormalities in children with such histories. Furthermore, white matter abnormalities were associated with duration of time in the orphanage and with inattention and hyperactivity scores. It is suspected that the observed white matter abnormalities are associated with multiple depriving factors (e.g., poor prenatal care, postnatal stress) associated with institutional caregiving.

Preliminary evidence for sensitive periods in the effect of childhood sexual abuse on regional brain development

Volumetric MRI scans from 26 women with repeated episodes of childhood sexual abuse and 17 healthy female comparison subjects (ages 18-22 years) were analyzed for sensitive period effects on hippocampal and amygdala volume, frontal cortex gray matter volume and corpus callosum area. Hippocampal volume was reduced in association with childhood sexual abuse at ages 3-5 years and ages 11-13 years. Corpus callosum was reduced with childhood sexual abuse at ages 9-10 years, and frontal cortex was attenuated in subjects with childhood sexual abuse at ages 14-16 years. Brain regions have unique windows of vulnerability to the effects of traumatic stress.

Early life stress as a risk factor for mental health: role of neurotrophins from rodents to non-human primates

Early adverse events can enhance stress responsiveness and lead to greater susceptibility for psychopathology at adulthood. The epigenetic factors involved in transducing specific features of the rearing environment into stable changes in brain and behavioural plasticity have only begun to be elucidated. Neurotrophic factors, such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), are affected by stress and play a major role in brain development and in the trophism of specific neuronal networks involved in cognitive function and in mood disorders. In addition to the central nervous system, these effectors are produced by peripheral tissues, thus being in a position to integrate the response to external challenges. In this paper we will review data, obtained from animal models, indicating that early maternal deprivation stress can affect neurotrophin levels. Maladaptive or repeated activation of NGF and BDNF, early during postnatal life, may influence stress sensitivity at adulthood and increase vulnerability for stress-related psychopathology.

Daytime cortisol secretion in 6-month-old twins: genetic and environmental contributions as a function of early familial adversity

BACKGROUND

Dysregulation of daytime cortisol activity has been associated with stress-related pathologies. Research suggests that early environmental adversity might shape cortisol activity. However, little is known about the genetic and environmental contributions to early cortisol and how this varies as a function of environmental circumstances. The goals of the study were to estimate the genetic and environmental contributions to daytime cortisol secretion in infant twins and to investigate whether these contributions varied as a function of familial adversity (FA).

METHODS

Participants were 517 6-month-old twins. Salivary cortisol was collected when the infants woke up at home and in the morning, upon arrival at the laboratory. Familial adversity was defined by seven perinatal and postnatal risk factors: maternal smoking during pregnancy, low birth weight, low family income, low maternal education, single parenthood, young motherhood, and maternal hostile/reactive behaviors. Genetic and environment contributions to cortisol activity were estimated for high (three risk factors or more: 21.3% of the sample) versus low FA.

RESULTS

Genetic factors accounted for cortisol levels in different ways: a moderate "main effect" of genes was found for home-based awakening cortisol, whereas the contribution of genes to morning cortisol was conditional to FA. Genetic factors accounted for most of the variance in morning cortisol in high family adversity but not in low family adversity.

CONCLUSIONS

Early FA modulates the heritability of morning cortisol in infants. The results are consistent with the diathesis-stress model, with genetic factors more likely to be expressed in adverse settings.

Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse

Maternal care influences hypothalamic-pituitary-adrenal (HPA) function in the rat through epigenetic programming of glucocorticoid receptor expression. In humans, childhood abuse alters HPA stress responses and increases the risk of suicide. We examined epigenetic differences in a neuron-specific glucocorticoid receptor (NR3C1) promoter between postmortem hippocampus obtained from suicide victims with a history of childhood abuse and those from either suicide victims with no childhood abuse or controls. We found decreased levels of glucocorticoid receptor mRNA, as well as mRNA transcripts bearing the glucocorticoid receptor 1F splice variant and increased cytosine methylation of an NR3C1 promoter. Patch-methylated NR3C1 promoter constructs that mimicked the methylation state in samples from abused suicide victims showed decreased NGFI-A transcription factor binding and NGFI-A-inducible gene transcription. These findings translate previous results from rat to humans and suggest a common effect of parental care on the epigenetic regulation of hippocampal glucocorticoid receptor expression.

Prenatal alcohol exposure increases vulnerability to stress and anxiety-like disorders in adulthood

Children and adults with fetal alcohol spectrum disorder (FASD) have elevated rates of depression and anxiety disorders compared to control populations. The effects of prenatal alcohol exposure (PAE) on anxiety, locomotor activity, and hormonal reactivity in male and female rats tested on the elevated plus maze (EPM), a task commonly used to assess anxiety-like behaviors in rodents, were examined. Pregnant dams were assigned to PAE, pair-fed (PF), or ad libitum-fed control (C) groups. At adulthood, half of all male (N= 60) and female (N= 60) PAE, PF, and C offspring were exposed to 10 days of chronic mild stress (CMS); the other half remained undisturbed. Animals were then tested on the EPM, and blood collected 30 min posttest for analysis of corticosterone (CORT), testosterone, estradiol, and progesterone. Overall, CMS exposure produced a significant anxiogenic profile. Moreover, CMS increased anxiety-like behavior in PAE males and females compared to controls and eliminated the locomotor hyperactivity observed in nonstressed PAE females. CMS also increased post-EPM CORT, testosterone, and progesterone levels in all groups, with CORT and progesterone levels significantly higher in PAE than in C females. By contrast, CMS selectively lowered estradiol levels in PAE and PF, but not C, females. CMS exposure reveals sexually dimorphic behavioral and endocrine alterations in PAE compared to C animals. Together, these data suggest the possibility that fetal reprogramming of hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) systems by alcohol may underlie, at least partly, an enhanced susceptibility of fetal alcohol-exposed offspring to depression/anxiety-like disorders in adulthood.

Subchronic stress-induced depressive behavior in ovariectomized mice

AIMS

Mood disorders including depression are more common in women than men, particularly in times of lower estradiol levels. In this study, we investigated the effect of estrogen on emotional behavior in mice in a stress environment.

MAIN METHODS

Female mice were divided into four groups: two groups were ovariectomized (OVX) and two were sham-operated. One group each of OVX and sham mice was kept in a normal environment and the other groups were assigned to a daily stress (1 h/day) for 7 days from 5 days after operation. On the 14th day after operation, subjects were measured to assess behavioral specificity, locomotor activity, elevated plus-maze (EPM) behavior, passive avoidance (PA) behavior and forced swimming behavior.

KEY FINDINGS

The OVX plus stress (OVX+S) group showed a significant prolongation of immobility compared with the other groups. In all the groups there were no changes in locomotor activity, EPM behavior or PA behavior. We further examined the effect of estrogen against depressive behavior in the OVX+S group. The vehicle or 17beta-estradiol (E2) was administered s.c. to OVX+S mice for 4 days beginning on post-operative day 11. Subchronic E2 treatment decreased the stress response and improved depressive behavior relative to the vehicle group.

SIGNIFICANCE

These data have important implications regarding the prevention of depression in postmenopausal women undergoing estrogen therapy.

Changes in plasma levels of BDNF and NGF reveal a gender-selective vulnerability to early adversity in rhesus macaques

Early stressful events can increase vulnerability for psychopathology, although knowledge on the effectors is still limited. Here we tested the hypothesis that peripheral levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), which are involved in the response to stress and in the pathophysiology of anxiety and depression, might be affected in a non-human primate model of adverse rearing. Males and females rhesus macaques reared with their mothers (MR) or in peer-only groups (PR) were used as experimental subjects. BDNF, NGF, adrenocorticotropic hormone (ACTH), cortisol and growth hormone (GH) were determined at baseline on postnatal days (PND) 14, 30 and 60 by means of specific ELISA and RIA procedures. In addition, behavior was assessed on PND 7, 14, 21, 30 (Brazelton test) and 60 (home cage observation). Data indicate gender differences in basal levels of BDNF throughout development. Peer-rearing increased significantly BDNF levels only in females. In addition, while all peer-reared subjects showed high levels of stereotypies and self-directed behaviors, behavioral passivity was selectively increased in females. By contrast, NGF levels were increased in response to peer-rearing only in males, and correlated positively with other "classic" endocrine responses to stress, such as cortisol and GH. Our data identify BDNF and NGF as neuroendocrine markers underlying differential responses to maternal deprivation in males and females rhesus macaques. The selective changes in BDNF levels in females could help explain the greater vulnerability to mood disorders of this gender reported in humans.

Neurostructural imaging findings in children with post-traumatic stress disorder: brief review

Child maltreatment has been associated with different psychiatric disorders. Studies on both animals and humans have suggested that some brain areas would be directly affected by severe psychological trauma. The pathophysiology of post-traumatic stress disorder (PTSD) appears to be related to a complex interaction involving genetic and environmental factors. Advanced neuroimaging techniques have been used to investigate neurofunctional and neurostructural abnormalities in children, adolescents, and adults with PTSD. This review examined structural brain imaging studies that were performed in abused and traumatized children, and discusses the possible biological mechanisms involved in the pathophysiology of PTSD, the implications and future directions for magnetic resonance imaging (MRI) studies. Published reports in refereed journals were reviewed by searching Medline and examining references of the articles related to structural neuroimaging of PTSD. Structural MRI studies have been performed in adults and children to evaluate the volumetric brain alterations in the PTSD population. In contrast with studies involving adults, in which hippocampus volumetric reduction was the most consistent finding, studies involving children and adolescents with PTSD have demonstrated smaller medial and posterior portions of the corpus callosum.

Structural brain abnormalities in borderline personality disorder: a voxel-based morphometry study

Imaging studies using region-of-interest morphometry and positron emission tomography have contributed to our understanding of structural and functional abnormalities in borderline personality disorder (BPD); however, both methods have practical limitations to their usefulness for exploratory studies of brain-behavior relationships. We used voxel-based morphometry (VBM) in 34 subjects with BPD and 30 healthy control (HC) subjects to study effects of diagnosis, gender, childhood sexual abuse, depressed mood, impulsivity and aggression on group differences. VBM is a computer-based method for whole brain analysis that combines the advantages of a functional study with a structural method. The BPD subjects, diagnosed with the Diagnostic Interview for Borderline Patients and the International Personality Disorders Examination, were compared with 30 HC subjects, with age and gender covaried. Analyses were repeated separately by gender and, in women, by histories of childhood sexual abuse. Depressed mood, impulsivity, and aggression were covaried in separate analyses. Compared with HC, BPD subjects had significant bilateral reductions in gray matter concentrations in ventral cingulate gyrus and several regions of the medial temporal lobe, including the hippocampus, amygdala, parahippocampal gyrus, and uncus. BPD women (and abused BPD women), but not BPD men, had significant reductions in medial temporal lobe, including the amygdala. BPD men, but not BPD women, showed diminished gray matter concentrations in the anterior cingulate gyrus compared with findings in HC subjects. Covarying for depressed mood rendered group differences non-significant in the ventral cingulate but had little effect on differences in medial temporal cortex. Covarying for aggression (LHA) had relatively little effect on group differences, while covarying for impulsivity, as determined by the Barratt Impulsiveness Scale, rendered all previously noted voxel-level group differences non-significant. Diminished gray matter in the prefrontal cortex and the medial temporal cortex may mediate the dysregulation of impulse and affect in BPD. Group differences varied greatly by gender, levels of depression, and impulsivity. VBM is an efficient method for exploratory study of brain-behavior relationships.

Neonatal handling and the maternal odor preference in rat pups: involvement of monoamines and cyclic AMP response element-binding protein pathway in the olfactory bulb

Early-life environmental events, such as the handling procedure, can induce long-lasting alterations upon several behavioral and neuroendocrine systems. However, the changes within the pups that could be causally related to the effects in adulthood are still poorly understood. In the present study, we analyzed the effects of neonatal handling on behavioral (maternal odor preference) and biochemical (cyclic AMP response element-binding protein (CREB) phosphorylation, noradrenaline (NA), and serotonin (5-HT) levels in the olfactory bulb (OB)) parameters in 7-day-old male and female rat pups. Repeated handling (RH) abolished preference for the maternal odor in female pups compared with nonhandled (NH) and the single-handled (SH) ones, while in RH males the preference was not different than NH and SH groups. In both male and female pups, RH decreased NA activity in the OB, but 5-HT activity increased only in males. Since preference for the maternal odor involves the synergic action of NA and 5-HT in the OB, the maintenance of the behavior in RH males could be related to the increased 5-HT activity, in spite of reduction in the NA activity in the OB. RH did not alter CREB phosphorylation in the OB of both male and females compared with NH pups. The repeated handling procedure can affect the behavior of rat pups in response to the maternal odor and biochemical parameters related to the olfactory learning mechanism. Sex differences were already detected in 7-day-old pups. Although the responsiveness of the hypothalamic-pituitary-adrenal axis to stressors is reduced in the neonatal period, environmental interventions may impact behavioral and biochemical mechanisms relevant to the animal at that early age.

Suicide attempters: biological stressmarkers and adverse life events

Risk factors for suicidal behaviour include adverse life events as well as biochemical parameters acting, e.g. within the hypothalamic-pituitary-adrenal axis and/or monoaminergic systems. The aim of the present investigation was to study stressful life events and biological stress markers among former psychiatric inpatients, who were followed up 12 years after an index suicide attempt. At the time of the index suicide attempt, and before treatment, cerebrospinal fluid (CSF) samples were taken, and 24 h (h) urine (U) was collected. 3-Methoxy-4-hydroxyphenylglycole (MHPG) in CSF and 24 h urinary samples of cortisol and noradrenaline/adrenaline (NA/A) were analysed. Data concerning stressful life events were collected retrospectively from all participants in the study through semi-structured interviews at follow-up. We found that patients who reported sexual abuse during childhood and adolescence had significantly higher levels of CSF-MHPG and U-NA/A, than those who had not. Low 24 h U-cortisol was associated with feelings of neglect during childhood and adolescence. In conclusion, this study has shown significant and discrepant biological stress-system findings in relation to some adverse life events.

Psychopharmacotherapy of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a psychiatric disorder that develops after a psychological trauma usually caused by a situation perceived as deeply threatening to a person's life or integrity. Complex neurobiological changes triggered by such a traumatic and stressful experience may explain a wide range of PTSD symptoms and provide the rationale for psychopharmacological treatment. Selective serotonin-reuptake inhibitors make the first-line treatment of PTSD. Clinical experience has shown that they are more effective than noradrenalin-reuptake inhibitors or tricyclic antidepressants. Antipsychotic drugs, especially atypical ones, have been shown effective in PTSD patients with psychotic characteristics or refractoriness to other treatments. Mood stabilizers seem to reduce mostly autonomous overreactions to stress, whereas the evidence for effectiveness of monoamine oxidase inhibitors is largely inconclusive. Other groups of medications, such as serotonin agonists and antagonists, new antidepressants, dual inhibitors of serotonin- and noradrenalin-reuptake, anticonvulsants, and opiate antagonists are also sometimes used in PTSD treatment. However, as shown in the present review, most clinical studies performed to date to investigate the effectiveness of different psychopharmacological agents in the therapy of PTSD have serious limitations in terms of small sample size, lack of blinding and randomization, and small effect size. More rigorously designed, comparative studies are needed to determine the usefulness, efficacy, tolerability, and safety of particular psychopharmaceutical drugs in the treatment of this therapeutically and functionally challenging disorder.

Understanding the potency of stressful early life experiences on brain and body function

Early life experiences have powerful effects on the brain and body lasting throughout the entire life span and influencing brain function, behavior, and the risk for a number of systemic and mental disorders. Animal models of early life adversity are providing mechanistic insights, including glimpses into the fascinating world that is now called "epigenetics" as well as the role of naturally occurring alleles of a number of genes. These studies also provide insights into the adaptive value as well as the negative consequences, of early life stress, exposure to novelty, and poor-quality vs good-quality maternal care. Animal models begin to provide a mechanistic basis for understanding how brain development and physiological functioning is affected in children exposed to early life abuse and neglect, where there is a burgeoning literature on the consequences for physical health and emotional and cognitive development. An important goal is to identify interventions that are likely to be most effective in early life and some guidelines are provided.

Early weaning results in less active behaviour, accompanied by lower 5-HT1A and higher 5-HT2A receptor mRNA expression in specific brain regions of female pigs

In rodents and humans stressful events in early life e.g. maternal deprivation, can increase sensitivity to stress in later life. Humans may become more susceptible to mood disorders, e.g. depression. In livestock species, such as pigs, early weaning is a form of maternal deprivation. We investigated behavioural consequences in 99 female pigs weaned at three different ages (12, 21 and 42 days; d12, d21, d42). Pigs were habituated to an open field arena over 6 days before being given 5-min open-field tests over three subsequent days (days 77-79). Early-weaned pigs (d12) showed behavioural inhibition (reduced vocalisations and lower activity) compared with later-weaned pigs, although in all groups these measures declined over the three tests, so this treatment difference might reflect more rapid habituation to the test in d12 pigs. Long-term effects on mood-related 5-HT receptor subtypes were measured in the brain at 90 days in a random sample of the d12 (n=8) and d42 pigs (n=8), using (3)H-ligand-binding and autoradiography and in situ hybridisation histochemistry. There were no differences between weaning ages in binding of (3)H-8-OH-DPAT (5-HT(1A) receptor agonist) or of (3)H-ketanserin (5-HT(2A) receptor antagonist) to any brain region studied. In d12 pigs, 5-HT(1A) receptor mRNA expression per unit area was 29%, 63%, 52% and 64% lower than in d42 pigs in the parvocellular PVN, amygdala and hippocampal dentate gyrus and pyramidal cell layer, respectively. The ratio of expression per cell to expressing cells per unit area was also lower, by 31%, in the pars horizontalis of the PVN in d12 pigs. Conversely, 5-HT(2A) receptor mRNA was expressed at a 25% and 28% higher density per unit area in the amygdala and pyramidal cell layer of the hippocampus, respectively, in these d12 pigs. In individual pigs, across brain regions, 5-HT(1A) receptor mRNA data were 70-79% correlated with binding data but no correlation was found for 5-HT(2A) data, suggesting different regulatory mechanisms. The behavioural and neurobiological responses to early weaning might represent either dysfunction or adaptation. Further investigation is required.

Social support and resilience to stress across the life span: a neurobiologic framework

This review discusses selected neurobiologic and genetic factors-including noradrenergic and hypothalamic-pituitary-adrenal axis markers, oxytocin pathways, and serotonin transporter and brain-derived neurotrophic factor gene polymorphisms-in the context of resilience to stress, with an emphasis on social support. Social support's impact on medical and psychiatric health outcomes is reviewed, and putative mediators are discussed. The reviewed literature indicates that social support is exceptionally important to maintaining good physical and psychological health in the presence of genetic, developmental, and other environmental risks. Future studies should continue to explore the neurobiologic factors associated with social support's contribution to stress resilience.

Corpus callosum in maltreated children with posttraumatic stress disorder: a diffusion tensor imaging study

Contrary to expectations derived from preclinical studies of the effects of stress, and imaging studies of adults with posttraumatic stress disorder (PTSD), there is no evidence of hippocampus atrophy in children with PTSD. Multiple pediatric studies have reported reductions in the corpus callosum--the primary white matter tract in the brain. Consequently, in the present study, diffusion tensor imaging was used to assess white matter integrity in the corpus callosum in 17 maltreated children with PTSD and 15 demographically matched normal controls. Children with PTSD had reduced fractional anisotropy in the medial and posterior corpus, a region which contains interhemispheric projections from brain structures involved in circuits that mediate the processing of emotional stimuli and various memory functions--core disturbances associated with a history of trauma. Further exploration of the effects of stress on the corpus callosum and white matter development appears a promising strategy to better understand the pathophysiology of PTSD in children.

Central effects of stress hormones in health and disease: Understanding the protective and damaging effects of stress and stress mediators

Stress begins in the brain and affects the brain, as well as the rest of the body. Acute stress responses promote adaptation and survival via responses of neural, cardiovascular, autonomic, immune and metabolic systems. Chronic stress can promote and exacerbate pathophysiology through the same systems that are dysregulated. The burden of chronic stress and accompanying changes in personal behaviors (smoking, eating too much, drinking, poor quality sleep; otherwise referred to as "lifestyle") is called allostatic overload. Brain regions such as hippocampus, prefrontal cortex and amygdala respond to acute and chronic stress and show changes in morphology and chemistry that are largely reversible if the chronic stress lasts for weeks. However, it is not clear whether prolonged stress for many months or years may have irreversible effects on the brain. The adaptive plasticity of chronic stress involves many mediators, including glucocorticoids, excitatory amino acids, endogenous factors such as brain neurotrophic factor (BDNF), polysialated neural cell adhesion molecule (PSA-NCAM) and tissue plasminogen activator (tPA). The role of this stress-induced remodeling of neural circuitry is discussed in relation to psychiatric illnesses, as well as chronic stress and the concept of top-down regulation of cognitive, autonomic and neuroendocrine function. This concept leads to a different way of regarding more holistic manipulations, such as physical activity and social support as an important complement to pharmaceutical therapy in treatment of the common phenomenon of being "stressed out". Policies of government and the private sector play an important role in this top-down view of minimizing the burden of chronic stress and related lifestyle (i.e. allostatic overload).