The link between childhood trauma and depression: insights from HPA axis studies in humans

Association between plasma IL-6 response to acute stress and early-life adversity in healthy adults

Increased production of peripheral cytokines and other pro-inflammatory markers has been linked to psychiatric disorders such as major depressive disorder and post-traumatic stress disorder. Recent research has pointed to early-life stress, particularly childhood maltreatment, as an independent and preventable risk factor for systemic inflammation in adulthood. Some data suggest that adults with a history of childhood maltreatment exhibit a heightened inflammatory response to acute stress challenge. To further elucidate the relationship between childhood maltreatment and pro-inflammatory cytokine production, we examined plasma IL-6 response to the Trier Social Stress Test (TSST) in 69 healthy adult subjects without depression or post-traumatic stress disorder. Serial plasma IL-6 concentrations were measured during a standardized psychosocial stressor in n=19 subjects with moderate-severe childhood maltreatment (MAL), and n=50 controls without maltreatment (CTL), as indicated by self-ratings on the childhood trauma questionnaire (CTQ). CTQ total scores were positively correlated with overall change in IL-6 response, as well as the maximum IL-6 concentration during the TSST. Greater acute IL-6 release and higher IL-6 concentrations over time were observed for the MAL group relative to the CTL group. Inflammation may be an important developmental mediator linking adverse experiences in early life to poor adult physical and mental health. The results of this preliminary study warrant further investigation in a larger sample.

Childhood social environment, emotional reactivity to stress, and mood and anxiety disorders across the life course

BACKGROUND

Adverse child environments are associated with the onset of mood and anxiety disorders in adulthood. The mechanisms underlying these life-course associations remain poorly understood. We investigate whether emotional reactivity to stress is a mechanism in the association between childhood environment characteristics and adult mood and anxiety disorders.

METHODS

Data are from the Study of Adult Development, a longitudinal study of men (N = 268) followed for nearly seven decades beginning in late adolescence. Childhood social environment characteristics were assessed during home visits and interviews with respondents' parents at entry into the study. Stress reactivity was assessed during respondents' sophomore year of college via physician exam. Onset of mood and anxiety disorders in adulthood was ascertained by research psychiatrists who completed chart reviews of interview, questionnaire, and physical exam data collected during repeated assessments from age 20 to 70.

RESULTS

Respondents with better overall childhood environments and a greater number of environmental strengths were at lower odds of developing a mood or anxiety disorder in adulthood than respondents with more adverse childhood environments. Higher stress reactivity was observed among respondents from families with lower socio-economic status and with childhood environments characterized by greater conflict and adversity. Elevated stress reactivity, in turn, predicted the onset of adult mood and anxiety disorders.

CONCLUSION

Heightened emotional reactivity in early adulthood is associated with both adverse childhood environments and elevated risk for developing mood and anxiety disorders in adulthood. Emotional reactivity may be one mechanism linking childhood adversity to mood and anxiety disorders in adulthood.

Animal models of early life stress: Implications for understanding resilience

In the mid-1950s, Levine and his colleagues reported that brief intermittent exposure to early life stress diminished indications of subsequent emotionality in rats. Here we review ongoing studies of a similar process in squirrel monkeys. Results from these animal models suggest that brief intermittent exposure to stress promotes the development of arousal regulation and resilience. Implications for programs designed to enhance resilience in human development are discussed.

A randomised controlled study of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced acute dystonia or parkinsonism

The objective of this study was to compare the effects of risperidone and olanzapine in schizophrenic patients with intolerant extrapyramidal side effects (EPS) on first generation antipsychotics. We conducted an 8-week, rater-blinded, flexible dose study. Seventy patients with schizophrenia, who met the DSM-IV research criteria of having neuroleptic-induced acute dystonia or parkinsonism, were randomly assigned to risperidone or olanzapine group. The primary outcome was a comparison of the incidence of concomitant anticholinergic drugs usage between the groups to manage their acute dystonia and parkinsonism. The average doses of risperidone and olanzapine from baseline to study end point were 1.8-3.5 mg/day and 7.7-11.7 mg/day, respectively. There were no significant differences in demographic data, severity of EPS or psychotic symptoms between the groups at baseline assessment. Patients taking risperidone had significantly higher incidence of using anticholinergic drugs to manage acute dystonia or parkinsonism overall during the study (OR = 5.17, 95%CI = 1.49-17.88, P = 0.013). There was no significant between-group difference in the changing of rating scales of EPS and psychotic symptoms. The results of our study favour olanzapine as a better choice in schizophrenic patients with intolerant EPS. Double-blinded, fixed dose and different ethnical study for EPS-intolerant schizophrenic patients is needed to confirm the results of our study.

Perceived early-life maternal care and the cortisol response to repeated psychosocial stress

BACKGROUND

In the past decade, a body of animal and human research has revealed a profound influence of early-life experiences, ranging from variations in parenting behaviour to severe adversity, on hypothalamic-pituitary-adrenal axis regulation in adulthood. In our own previous studies, we have shown how variations in early-life parental care influence the development of the hippocampus and modify the cortisol awakening response.

METHODS

In the present study, we investigated the influence of early-life maternal care on cortisol, heart rate and subjective psychological responses to the repeated administration of a psychosocial laboratory stressor in a population of 63 healthy young adults. Low, medium and high early-life maternal care groups were identified using the Parental Bonding Instrument.

RESULTS

Controlling for the effect of sex, we found an inverted u-shaped relation between increasing levels of maternal care and cortisol stress responsivity. Specifically, overall and stress-induced cortisol levels went from below normal in the low maternal care, to normal in the medium care, back to below normal in the high maternal care groups. We found no group differences with respect to heart rate and subjective psychological stress measures. Whereas low and high maternal care groups exhibited similarly low endocrine stress responses, their psychological profiles were opposed with increased levels of depression and anxiety and decreased self-esteem in the low care group.

LIMITATIONS

Sex was unequally distributed among maternal care groups, whereby the number of men with low maternal care was too small to allow introducing sex as a second between-group variable.

CONCLUSION

We discuss the potential significance of this dissociation between endocrine and psychological parameters with respect to stress vulnerability and resistance for each maternal care group.

A systematic review of hypothalamic-pituitary-adrenal axis function in schizophrenia: implications for mortality

There is convincing evidence that environmental stress plays a significant role in modifying both mental and physical health. The biological mechanisms linking stress to ill health are not fully understood, but significant evidence points to a central role of the stress axes; the hypothalamic- pituitary-adrenal (HPA) axis and the sympathetic nervous system. Together these two systems link the brain and the body and are crucial in maintaining homeostasis as well as improving an organism's survival chances in the face of environmental challenge. There is evidence of altered HPA axis function in people with a range of mental disorders, and this may in part explain the poor physical health of people with psychotic, mood and anxiety disorders. This paper systematically reviews HPA axis function in people with schizophrenia and relates this to the pattern of physical health seen in this disease. In summary, the evidence suggests people with schizophrenia can experience both hyper- and hypo-function of the HPA axis. It is likely that this contributes to the pattern of poor physical health and premature mortality suffered by people with schizophrenia, in particular the high rates of cardiovascular and metabolic disturbance.

From child maltreatment to adolescent cannabis abuse and dependence: a developmental cascade model

A developmental cascade model tested associations among child maltreatment, internalizing and externalizing psychopathology, social competence, and cannabis abuse and dependence symptoms in a longitudinal cohort (N = 415). Nested structural equation models evaluated continuity and cross-domain influences among broad multi-informant constructs across four developmental periods: age 7 to 9, 10 to 12, 13 to 15, and 15 to 18. Results indicated significant paths from child maltreatment to early externalizing and internalizing problems and social competence, as well as to cannabis abuse and dependence (CAD) symptoms in adolescence. Youth CAD symptoms were primarily related directly to child maltreatment and externalizing problems. Childhood internalizing symptoms contributed to later childhood decreases in social competence, which predicted increases in late adolescent externalizing problems. Using a developmental psychopathology framework, results are discussed in relation to cascade and transactional effects and the interplay between problem behaviors during childhood and development of CAD symptoms during early and late adolescence.

Sensitivity to the depressogenic effect of stress and HPA-axis reactivity in adolescence: a review of gender differences

Adolescence is characterized by major biological, psychological, and social challenges, as well as by an increase in depression rates. This review focuses on the association between stressful experiences and depression in adolescence, and the possible role of the hypothalamus-pituitary-adrenal cortex (HPA-)axis in this link. Adolescent girls have a higher probability to develop depressive symptoms than adolescent boys and preadolescents. Increasing evidence indicates that girls' higher risk of depression is partly brought about by an increased sensitivity for stressful life events, particularly interpersonal stressors, which are highly prevalent in adolescent girls. Genetic risk factors for depression, as well as those for stress sensitivity, are often expressed differently in girls and boys. Also environmental adversity tends to affect girls' stress responses more than those of boys. These gender-specific association patterns have been reported for both sensitivity to stressful life events and HPA-axis responses to social stress. Together, the findings suggest that girls are more malleable than boys in response to internal and external influences. This postulated greater malleability may be adaptive in many circumstances, but also brings along risk, such as an increased probability of depression.

Hippocampal dysfunction and cognitive impairments provoked by chronic early-life stress involve excessive activation of CRH receptors

Chronic stress impairs learning and memory in humans and rodents and disrupts long-term potentiation (LTP) in animal models. These effects are associated with structural changes in hippocampal neurons, including reduced dendritic arborization. Unlike the generally reversible effects of chronic stress on adult rat hippocampus, we have previously found that the effects of early-life stress endure and worsen during adulthood, yet the mechanisms for these clinically important sequelae are poorly understood. Stress promotes secretion of the neuropeptide corticotropin-releasing hormone (CRH) from hippocampal interneurons, activating receptors (CRF(1)) located on pyramidal cell dendrites. Additionally, chronic CRF(1) occupancy negatively affects dendritic arborization in mouse organotypic slice cultures, similar to the pattern observed in middle-aged, early-stressed (CES) rats. Here we found that CRH expression is augmented in hippocampus of middle-aged CES rats, and then tested whether the morphological defects and poor memory performance in these animals involve excessive activation of CRF(1) receptors. Central or peripheral administration of a CRF(1) blocker following the stress period improved memory performance of CES rats in novel-object recognition tests and in the Morris water maze. Consonant with these effects, the antagonist also prevented dendritic atrophy and LTP attenuation in CA1 Schaffer collateral synapses. Together, these data suggest that persistently elevated hippocampal CRH-CRF(1) interaction contributes importantly to the structural and cognitive impairments associated with early-life stress. Reducing CRF(1) occupancy post hoc normalized hippocampal function during middle age, thus offering potential mechanism-based therapeutic interventions for children affected by chronic stress.

[Childhood maltreatment and adult psychopathology: pathways to hypothalamic-pituitary-adrenal axis dysfunction]

OBJECTIVE

The aim of this paper was to examine the relationship between childhood maltreatment and adult psychopathology, as reflected in hypothalamic-pituitary-adrenal axis dysfunction.

METHOD

A selective review of the relevant literature was undertaken in order to identify key and illustrative research findings.

RESULTS

There is now a substantial body of preclinical and clinical evidence derived from a variety of experimental paradigms showing how early-life stress is related to hypothalamic-pituitary-adrenal axis function and psychological state in adulthood, and how that relationship can be modulated by other factors.

DISCUSSION

The risk for adult psychopathology and hypothalamic-pituitary-adrenal axis dysfunction is related to a complex interaction among multiple experiential factors, as well as to susceptibility genes that interact with those factors. Although acute hypothalamic-pituitary-adrenal axis responses to stress are generally adaptive, excessive responses can lead to deleterious effects. Early-life stress alters hypothalamic-pituitary-adrenal axis function and behavior, but the pattern of hypothalamic-pituitary-adrenal dysfunction and psychological outcome in adulthood reflect both the characteristics of the stressor and other modifying factors.

CONCLUSION

Research to date has identified multiple determinants of the hypothalamic-pituitary-adrenal axis dysfunction seen in adults with a history of childhood maltreatment or other early-life stress. Further work is needed to establish whether hypothalamic-pituitary-adrenal axis abnormalities in this context can be used to develop risk endophenotypes for psychiatric and physical illnesses.

Research review: the neurobiology and genetics of maltreatment and adversity

The neurobiological mechanisms by which childhood maltreatment heightens vulnerability to psychopathology remain poorly understood. It is likely that a complex interaction between environmental experiences (including poor caregiving) and an individual's genetic make-up influence neurobiological development across infancy and childhood, which in turn sets the stage for a child's psychological and emotional development. This review provides a concise synopsis of those studies investigating the neurobiological and genetic factors associated with childhood maltreatment and adversity. We first provide an overview of the neuroendocrine findings, drawing from animal and human studies. These studies indicate an association between early adversity and atypical development of the hypothalamic-pituitary-adrenal (HPA) axis stress response, which can predispose to psychiatric vulnerability in adulthood. We then review the neuroimaging findings of structural and functional brain differences in children and adults who have experienced childhood maltreatment. These studies offer evidence of several structural differences associated with early stress, most notably in the corpus callosum in children and the hippocampus in adults; functional studies have reported atypical activation of several brain regions, including decreased activity of the prefrontal cortex. Next we consider studies that suggest that the effect of environmental adversity may be conditional on an individual's genotype. We also briefly consider the possible role that epigenetic mechanisms might play in mediating the impact of early adversity. Finally we consider several ways in which the neurobiological and genetic research may be relevant to clinical practice and intervention.

Pathophysiology of depression: do we have any solid evidence of interest to clinicians?

Due to the clinical and etiological heterogeneity of major depressive disorder, it has been difficult to elucidate its pathophysiology. Current neurobiological theories with the most valid empirical foundation and the highest clinical relevance are reviewed with respect to their strengths and weaknesses. The selected theories are based on studies investigating psychosocial stress and stress hormones, neurotransmitters such as serotonin, norepinephrine, dopamine, glutamate and gamma-aminobutyric acid (GABA), neurocircuitry, neurotrophic factors, and circadian rhythms. Because all theories of depression apply to only some types of depressed patients but not others, and because depressive pathophysiology may vary considerably across the course of illness, the current extant knowledge argues against a unified hypothesis of depression. As a consequence, antidepressant treatments, including psychological and biological approaches, should be tailored for individual patients and disease states. Individual depression hypotheses based on neurobiological knowledge are discussed in terms of their interest to both clinicians in daily practice and clinical researchers developing novel therapies.

Early life stress followed by subsequent adult chronic stress potentiates anxiety and blunts hippocampal structural remodeling

Early life stress produces long-term alterations in cognition, emotionality, and stress responsiveness. The stress-sensitive hippocampal formation plays a role in producing many of these alterations. We report that adult male rats exposed to early life stress, in the form of maternal separation (MS), exhibit baseline impairment of hippocampal dependent memory and following three weeks of chronic restraint stress (CRS) exhibit heightened anxiety-like behavior and alterations in the morphology of hippocampal CA3 pyramidal neurons. Specifically, as measured by the object placement task, MS offspring demonstrated impaired spatial memory compared with nonmaternally separated rats (NMS). Moreover, compared with NMS rats, subsequent CRS exposure of MS rats increased novelty-induced corticosterone secretion and potentiated anxiety-like behavior as measured by the elevated plus maze. Further, CRS exposed MS rats did not exhibit shortening of apical dendritic length compared with nonstressed MS rats, whereas CRS exposed NMS rats did show significant dendritic shrinkage compared with nonstressed NMS rats. The blunted CRS-induced remodeling of apical dendritic length in MS rats is likely due to a baseline deficiency in dendritic length; MS rats exhibit a trend towards shorter apical dendrites in comparison to NMS rats. CRS exposure in both MS and NMS rats, however, induced a reduction in apical dendritic branching. Finally, there was a significant correlation between apical dendritic length and novelty-induced corticosterone level, while there was not a significant correlation with anxiety-like behavior. Overall, our results suggest preserved but blunted hippocampal structural plasticity in MS rats that is not sufficient to compensate for hippocampal dysfunction and hypersensitivity to CRS.

Structural changes in the hippocampus in major depressive disorder: contributions of disease and treatment

BACKGROUND

Previous magnetic resonance imaging (MRI) studies of patients with major depressive disorder (MDD) have consistently shown bilateral and unilateral reductions in hippocampal volume relative to healthy controls. Recent structural MRI studies have addressed the question of whether changes in the volume of hippocampal subregions may be associated with MDD.

METHODS

We used a comprehensive and reliable 3-dimensional tracing protocol that enables delineation of hippocampal subregions (head, body, tail) to study changes in the hippocampus of patients with MDD. We recruited 39 MDD patients (16 medicated, 23 unmedicated) and 34 healthy age- and sex-matched controls. We acquired images using a magnetization-prepared rapid acquisition gradient echo sequence on a 1.5-T scanner with a spatial resolution of 1.5 mm x 0.5 mm x 0.5 mm. We performed volumetric analyses, blinded to diagnosis, using the interactive software package Display. All volumes were adjusted for intracranial volume.

RESULTS

We found a significant reduction in the volume of the hippocampal tail bilaterally, right hippocampal head and right total hippocampus in MDD patients. Medicated MDD patients showed increased hippocampal body volume compared with both healthy controls and unmedicated patients.

LIMITATIONS

This study was cross-sectional. Further prospective studies are needed to determine the direct effect of antidepressant treatment.

CONCLUSION

Our results suggest that decreased hippocampal tail and hippocampal head volumes could be trait changes, whereas hippocampal body changes may be dependent on treatment. We showed that long-term antidepressant treatment may affect hippocampal volume in patients with MDD.

Epigenetic transmission of the impact of early stress across generations

BACKGROUND

Traumatic experiences in early life are risk factors for the development of behavioral and emotional disorders. Such disorders can persist through adulthood and have often been reported to be transmitted across generations.

METHODS

To investigate the transgenerational effect of early stress, mice were exposed to chronic and unpredictable maternal separation from postnatal day 1 to 14.

RESULTS

We show that chronic and unpredictable maternal separation induces depressive-like behaviors and alters the behavioral response to aversive environments in the separated animals when adult. Most of the behavioral alterations are further expressed by the offspring of males subjected to maternal separation, despite the fact that these males are reared normally. Chronic and unpredictable maternal separation also alters the profile of DNA methylation in the promoter of several candidate genes in the germline of the separated males. Comparable changes in DNA methylation are also present in the brain of the offspring and are associated with altered gene expression.

CONCLUSIONS

These findings highlight the negative impact of early stress on behavioral responses across generations and on the regulation of DNA methylation in the germline.

Early life programming and neurodevelopmental disorders

For more than a century, clinical investigators have focused on early life as a source of adult psychopathology. Early theories about psychic conflict and toxic parenting have been replaced by more recent formulations of complex interactions of genes and environment. Although the hypothesized mechanisms have evolved, a central notion remains: early life is a period of unique sensitivity during which experience confers enduring effects. The mechanisms for these effects remain almost as much a mystery today as they were a century ago. Recent studies suggest that maternal diet can program offspring growth and metabolic pathways, altering lifelong susceptibility to diabetes and obesity. If maternal psychosocial experience has similar programming effects on the developing offspring, one might expect a comparable contribution to neurodevelopmental disorders, including affective disorders, schizophrenia, autism, and eating disorders. Due to their early onset, prevalence, and chronicity, some of these disorders, such as depression and schizophrenia, are among the highest causes of disability worldwide according to the World Health Organization 2002 report. Consideration of the early life programming and transcriptional regulation in adult exposures supports a critical need to understand epigenetic mechanisms as a critical determinant in disease predisposition. Incorporating the latest insight gained from clinical and epidemiological studies with potential epigenetic mechanisms from basic research, the following review summarizes findings from a workshop on Early Life Programming and Neurodevelopmental Disorders held at the University of Pennsylvania in 2009.

Chronic childhood adversity and onset of psychopathology during three life stages: childhood, adolescence and adulthood

BACKGROUND

The aim is to report the individual and joint effects of a range of chronic childhood adversities on the first onset of a broad range of psychiatric disorders, and to evaluate their impact at different stages of the life course in a representative sample of the Mexican population.

METHOD

The data is from the Mexican National Comorbidity Survey (M-NCS), a stratified, multistage area probability sample of persons aged 18-65. The WHO World Mental Health Composite International Diagnostic Interview (WMH-CIDI) measured 12 childhood adversities, 20 psychiatric disorders and ages of onset. Discrete-time survival models were performed to estimate the odds of disorder onset.

RESULTS

In bivariate models, all adversities (except economic adversity and parental death) were significant predictors of psychopathology; however in multivariate models which correct for the clustering of adversities, family dysfunction and abuse adversities were the strongest and most consistent predictors of all four classes of psychopathologies examined (mood, anxiety, substance use and externalizing), and for the most part, over all three life course stages (childhood, adolescence and adulthood). The effect of the number of adversities was nonlinear such that although the odds of disorder onset increased with increasing numbers of adversities, the odds increased at a decreasing rate.

CONCLUSIONS

Childhood family dysfunction and abuse is a strong predictor of the onset of psychopathology throughout the life course, consistent with evidence for the enduring effects of chronic stress on brain structures involved in many psychiatric disorders and with stress-sensitization models of psychopathology.

Eating ourselves to death (and despair): the contribution of adiposity and inflammation to depression

Obesity and related metabolic conditions are of epidemic proportions in most of the world, affecting both adults and children. The accumulation of lipids in the body in the form of white adipose tissue in the abdomen is now known to activate innate immune mechanisms. Lipid accumulation causes adipocytes to directly secrete the cytokines interleukin (IL) 6 and tumor necrosis factor alpha (TNFalpha), but also monocyte chemoattractant protein 1 (MCP-1), which results in the accumulation of leukocytes in fat tissue. This sets up a chronic inflammatory state which is known to mediate the association between obesity and conditions such as cardiovascular disease, type 2 diabetes, and cancer. There is also a substantial literature linking inflammation with risk for depression. This includes the observations that: (1) people with inflammatory diseases such as multiple sclerosis, cardiovascular disease, and psoriasis have elevated rates of depression; (2) many people administered inflammatory cytokines such as interferon alpha develop depression that is indistinguishable from depression in non-medically ill populations; (3) a significant proportion of depressed persons show upregulation of inflammatory factors such as IL-6, C-reactive protein, and TNFalpha; (4) inflammatory cytokines can interact with virtually every pathophysiologic domain relevant to depression, including neurotransmitter metabolism, neuroendocrine function, and synaptic plasticity. While many factors may contribute to the association between inflammatory mediators and depression, we hypothesize that increased adiposity may be one causal pathway. Mediational analysis suggests a bi-directional association between adiposity and depression, with inflammation possibly playing an intermediary role.

Association of childhood trauma with cognitive function in healthy adults: a pilot study

BACKGROUND

Animal and human studies suggest that stress experienced early in life has detrimental consequences on brain development, including brain regions involved in cognitive function. Cognitive changes are cardinal features of depression and posttraumatic stress disorder. Early-life trauma is a major risk factor for these disorders. Only few studies have measured the long-term consequences of childhood trauma on cognitive function in healthy adults.

METHODS

In this pilot study, we investigated the relationship between childhood trauma exposure and cognitive function in 47 healthy adults, who were identified as part of a larger study from the general population in Wichita, KS. We used the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Wide-Range-Achievement-Test (WRAT-3) to examine cognitive function and individual achievement. Type and severity of childhood trauma was assessed by the Childhood Trauma Questionnaire (CTQ). Data were analyzed using multiple linear regression on CANTAB measures with primary predictors (CTQ scales) and potential confounders (age, sex, education, income).

RESULTS

Specific CTQ scales were significantly associated with measures of cognitive function. Emotional abuse was associated with impaired spatial working memory performance. Physical neglect correlated with impaired spatial working memory and pattern recognition memory. Sexual abuse and physical neglect were negatively associated with WRAT-3 scores. However, the association did not reach the significance level of p < 0.01.

CONCLUSIONS

Our results suggest that physical neglect and emotional abuse might be associated with memory deficits in adulthood, which in turn might pose a risk factor for the development of psychopathology.

Chronic stress effects on hippocampal structure and synaptic function: relevance for depression and normalization by anti-glucocorticoid treatment

Exposure of an organism to environmental challenges activates two hormonal systems that help the organism to adapt. As part of this adaptational process, brain processes are changed such that appropriate behavioral strategies are selected that allow optimal performance at the short term, while relevant information is stored for the future. Over the past years it has become evident that chronic uncontrollable and unpredictable stress also exerts profound effects on structure and function of limbic neurons, but the impact of chronic stress is not a mere accumulation of repeated episodes of acute stress exposure. Dendritic trees are reduced in some regions but expanded in others, and cells are generally exposed to a higher calcium load upon depolarization. Synaptic strengthening is largely impaired. Neurotransmitter responses are also changed, e.g., responses to serotonin. We here discuss: (a) the main cellular effects after chronic stress with emphasis on the hippocampus, (b) how such effects could contribute to the development of psychopathology in genetically vulnerable individuals, and (c) their normalization by brief treatment with anti-glucocorticoids.

Interaction of FKBP5 with childhood adversity on risk for post-traumatic stress disorder

FKBP5 regulates the cortisol-binding affinity and nuclear translocation of the glucocorticoid receptor. Polymorphisms at the FKBP5 locus have been associated with increased recurrence risk of depressive episodes and rapid response to antidepressant treatment. A recent study showed that FKBP5 genotypes moderated the risk of post-traumatic stress disorder (PTSD) symptoms associated with childhood maltreatment. One thousand one hundred forty-three European Americans (EAs) and 1284 African Americans (AAs) recruited for studies of the genetics of substance dependence were also screened for lifetime PTSD. Four single-nucleotide polymorphisms (SNPs) in FKBP5, rs3800373, rs9296158, rs1360780, and rs9470080, were genotyped on the complete sample. Logistic regression analyses were performed to explore the interactive effect of FKBP5 polymorphisms and childhood adversity on the risk for PTSD. After correction for multiple testing, childhood adversity significantly increased the risk for PTSD. FKBP5 genotypes were not associated with the development of the disorder. In AAs, one of the SNPs, rs9470080, moderated the risk of PTSD that was associated with childhood abuse. Without childhood adverse experiences, participants with the TT genotype of this SNP had the lowest risk for PTSD, whereas they had the highest risk for PTSD after childhood adversity exposure. In addition, in EAs, alcohol dependence was observed to interact with childhood adverse experiences, and also FKBP5 polymorphisms, to increase the risk for PTSD. This study provides further evidence of a gene x environment effect of FKBP5 and childhood abuse on the risk for PTSD in AAs. Further study is required in other populations.

Cortisol function among early school-aged homeless children

Homelessness represents a context of extreme poverty and risk for child development. This study compared the relative influence of two classes of risk in the context of homelessness. Levels of socioeconomic resource-related risk and negative lifetime events were examined with respect to morning cortisol levels and cortisol response to a set of cognitive tasks. Participants were 66 children between the ages of 4 and 7 years staying in an emergency shelter for families. Adversities largely reflecting family level negative life events predicted higher levels of morning cortisol and differences in initial level and change over the course of the session of cognitive tasks. In contrast, a socioeconomic cumulative risk score was not associated with morning or session-related differences in cortisol.

Gender-related endocrinological dysfunction and mental disorders

PURPOSE OF REVIEW

The association between endocrine and neuropsychiatric disorders was established long ago, with solid evidence. According to a multidimensional model of mental disorders, one can conceptualize sex and gender-related endocrinological dysfunctions as a cluster of risk factors included in the biological determinants of those disorders.

RECENT FINDINGS

Gender and sexual dimorphism in brain functions and pathways may have a main impact and synergistic effects on health differences in both men and women. To explain these differences, hormonal reactivity to stress, sex hormones and gene-environment interactions are among the most researched mechanisms.

SUMMARY

In this paper, we review updated data on sex and gender differences in stress reactivity, concerning the hypothalamic-pituitary-adrenal axis, endocrinological dysfunction and vulnerability to major psychiatric disorders, in a stress-diathesis approach. Mainly schizophrenia and affective disorders are discussed, according to recent investigation, in terms of early determinants of stress reactivity, the interplay of genetic expression and gender role, their responsibility in biological modulation and their hypothetical contribution to explain gender differences in prevalence and clinical aspects of mental disorders.

High susceptibility to chronic social stress is associated with a depression-like phenotype

Chronic stress is a key risk factor for a variety of diseases, including depression. There is a large degree of individual variation in the ability to recover successfully from a chronic stress exposure, but the determinants of this individual stress susceptibility are still poorly understood. We recently developed a novel mouse paradigm for chronic social stress during adolescence, which closely mimics the human condition of chronic social stress in respect to construct, face and predictive validity. By applying this chronic stress model to a large number of animals we aimed at identifying individuals that are either resilient or vulnerable to the persistent effects of chronic social stress exposure. Animals showing markedly elevated basal corticosterone levels 5 weeks following the end of the stress paradigm were considered "vulnerable", whereas individuals recovering quickly and being indistinguishable from controls were classified as "resilient". Stress vulnerability was associated with an increased level of corticotropin-releasing hormone in the paraventricular nucleus, decreased hippocampal mineralocorticoid receptor expression as well as increased anxiety- and depression-like behavior compared to resilient and control animals. In summary, we show that by using a large cohort of animals it is possible to select individuals that are vulnerable or resilient to the lasting effects of chronic social stress. The vulnerable phenotype mimics many aspects of stress-related human affective disorders and this may be used as a novel approach to study depression in an animal model, ultimately contributing to a better understanding and treatment of stress-related disorders.

Resting-state functional MRI in depression unmasks increased connectivity between networks via the dorsal nexus

To better understand intrinsic brain connections in major depression, we used a neuroimaging technique that measures resting state functional connectivity using functional MRI (fMRI). Three different brain networks--the cognitive control network, default mode network, and affective network--were investigated. Compared with controls, in depressed subjects each of these three networks had increased connectivity to the same bilateral dorsal medial prefrontal cortex region, an area that we term the dorsal nexus. The dorsal nexus demonstrated dramatically increased depression-associated fMRI connectivity with large portions of each of the three networks. The discovery that these regions are linked together through the dorsal nexus provides a potential mechanism to explain how symptoms of major depression thought to arise in distinct networks--decreased ability to focus on cognitive tasks, rumination, excessive self-focus, increased vigilance, and emotional, visceral, and autonomic dysregulation--could occur concurrently and behave synergistically. It suggests that the newly identified dorsal nexus plays a critical role in depressive symptomatology, in effect "hot wiring" networks together; it further suggests that reducing increased connectivity of the dorsal nexus presents a potential therapeutic target.

Psychiatric aspects of chronic fatigue syndrome and fibromyalgia

Chronic fatigue syndrome and/or fibromyalgia (CFS/FM) consists of highly overlapping, medically unexplained symptoms, including long-lasting fatigue, effort intolerance, cognitive dysfunction, and widespread pain and tenderness. CFS/FM often seems to be triggered by infections and physical trauma, but depression, sleep disturbances, and personality may also be involved. Moreover, dysregulation of the stress system, the immune system, and central pain mechanisms may determine the pathophysiology of the illness, leading to a loss of capacity to adapt to all kind of stressors. CFS/FM patients can be best helped by a pragmatic and individualized approach aimed at adjusting lifestyle and optimizing self-care, which in the long run may contribute to a restoration of physical and mental adaptability. Future psychiatric research into CFS/FM should focus on the complex interrelationships among pain/fatigue, stress/depression, and personality, as well as on processes of therapeutic change and the advantages of customized treatment.

Cortisol and alpha amylase reactivity and timing of puberty: vulnerabilities for antisocial behaviour in young adolescents

The theoretical framework proposed that cortisol and saliva alpha amylase (sAA) reactivitiy are vulnerabilities for antisocial behaviour. These indices of hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medulary (SAM) components of the stress system, respectively, were considered vulnerabilities that also interact with the putative stressful transition of timing of puberty to predispose adolescents toward antisocial behaviour. The sample consisted of 8- to-13-year-old boys and girls (N=135) and a parent. For boys, timing of puberty moderated the association between cortisol and sAA reactivity and antisocial behaviour. Higher cortisol reactivity in later timing boys was related to a composite index of antisocial behaviour and rule-breaking behaviour problems. In contrast, lower sAA reactivity and earlier timing of puberty in boys was related to rule breaking and conduct disorder symptoms. The interaction between timing of puberty and HPA or SAM regulation and timing of puberty in boys suggests that reproductive, neuroendocrine mechanisms may be involved in the extensively documented adverse consequences of off-time pubertal development.

Attenuation of cortisol across development for victims of sexual abuse

Inconsistencies exist in literature examining hypothalamic-pituitary-adrenal (HPA) axis activity in children and adults who have experienced childhood abuse. Hence, the extent and manner to which childhood abuse may disrupt HPA axis development is largely unknown. To address these inconsistencies, the developmental course of nonstress cortisol in a long-term longitudinal study was assessed at six time points from childhood through adolescence and into young adulthood to determine whether childhood abuse results in disrupted cortisol activity. Nonstress, morning cortisol was measured in 84 females with confirmed familial sexual abuse and 89 nonabused, comparison females. Although dynamically controlling for co-occurring depression and anxiety, hierarchical linear modeling (HLM) showed that relative to comparison females, the linear trend for abused females was significantly less steep when cortisol was examined across development from age 6 to age 30, t (1, 180) = -2.55, p < .01, indicating attenuation in cortisol activity starting in adolescence with significantly lower levels of cortisol by early adulthood, F (1, 162) = 4.78, p < .01. As a more direct test of the attenuation hypothesis, supplemental HLM analyses of data arrayed by time since the disclosure of abuse indicated that cortisol activity was initially significantly higher, t (1, 425) = 2.18, p < .05, and slopes were significantly less steep t (1, 205) = -2.66, p < .01, for abused females. These findings demonstrate how the experience of childhood abuse might disrupt the neurobiology of stress, providing some support for the attenuation hypothesis that victims of abuse may experience cortisol hyposecretion subsequent to a period of heightened secretion.

Depression gets old fast: do stress and depression accelerate cell aging?

Depression has been likened to a state of "accelerated aging," and depressed individuals have a higher incidence of various diseases of aging, such as cardiovascular and cerebrovascular diseases, metabolic syndrome, and dementia. Chronic exposure to certain interlinked biochemical pathways that mediate stress-related depression may contribute to "accelerated aging," cell damage, and certain comorbid medical illnesses. Biochemical mediators explored in this theoretical review include the hypothalamic-pituitary-adrenal axis (e.g., hyper- or hypoactivation of glucocorticoid receptors), neurosteroids, such as dehydroepiandrosterone and allopregnanolone, brain-derived neurotrophic factor, excitotoxicity, oxidative and inflammatory stress, and disturbances of the telomere/telomerase maintenance system. A better appreciation of the role of these mediators in depressive illness could lead to refined models of depression, to a re-conceptualization of depression as a whole body disease rather than just a "mental illness," and to the rational development of new classes of medications to treat depression and its related medical comorbidities.

Cognitive modulation of endocrine responses to CRH stimulation in healthy subjects

BACKGROUND

The hypothalamic-pituitary adrenal (HPA) axis is critical for biobehavioral adaptation to challenge and appears dysregulated in a range of psychiatric disorders. Its precise role in psychopathology remains unclear and discrepant and difficult to explain findings abound in the clinical literature. Basic research suggests this system is sensitive to psychosocial cues, but psychosocial milieu factors are rarely controlled or examined in psychiatric studies using biological probes of the HPA axis. To test the hypothesis that psychological factors might complicate HPA study results even in direct, pharmacological challenge paradigms, endocrine responses to corticotropin-releasing hormone (CRH) were examined under two different cognitive preparation conditions.

METHODS

Healthy subjects (n=32) received standard instructions or a cognitive intervention (CI) prior to injection with CRH and placebo, given on separate days in random order. The CI combined access to control over drug exposure with novelty reduction and coping enhancement. Blood samples were obtained via intravenous catheter before and after CRH.

RESULTS

Cognitive intervention reduced corticotropin (ACTH) levels, but only when CRH was given first (intervention by order interaction). It did not reduce cortisol response. The CI and visit (1st or 2nd) both impacted cortisol levels on placebo day.

CONCLUSIONS

Modifiable psychological factors may amplify or inhibit HPA axis activity in pharmacological activation paradigms, including CRH stimulation tests. The factors manipulated by the CI (novelty/familiarity, control and coping) may have particular salience to the HPA axis. Differential sensitivity to such factors could impact results in studies applying biological HPA probes to psychiatric populations.

Staging perspectives in neurodevelopmental aspects of neuropsychiatry: agents, phases and ages at expression

Neurodevelopmental risk factors have assumed a critical role in prevailing notions concerning the etiopathogenesis of neuropsychiatric disorders. Staging, diagnostic elements at which phase of disease is determined, provides a means of conceptualizing the degree and extent of factors affecting brain development trajectories, but is concurrently specified through the particular interactions of genes and environment unique to each individual case. For present purposes, staging perspectives in neurodevelopmental aspects of the disease processes are considered from conditions giving rise to neurodevelopmental staging in affective states, adolescence, dopamine disease states, and autism spectrum disorders. Three major aspects influencing the eventual course of individual developmental trajectories appear to possess an essential determinant influence upon outcome: (i) the type of agent that interferes with brain development, whether chemical, immune system activating or absent (anoxia/hypoxia), (ii) the phase of brain development at which the agent exerts disruption, whether prenatal, postnatal, or adolescent, and (iii) the age of expression of structural and functional abnormalities. Clinical staging may be assumed at any or each developmental phase. The present perspective offers both a challenge to bring further order to diagnosis, intervention, and prognosis and a statement regarding the extreme complexities and interwoven intricacies of epigenetic factors, biomarkers, and neurobehavioral entities that aggravate currents notions of the neuropsychiatric disorders.

Oxytocin and Major Depressive Disorder: Experimental and Clinical Evidence for Links to Aetiology and Possible Treatment

Affective disorders represent the most common psychiatric diseases, with substantial co-morbidity existing between major depressive disorders (MDD) and anxiety disorders. The lack of truly novel acting compounds has led to non-monoaminergic based research and hypotheses in recent years. The large number of brain neuropeptides, characterized by discrete synthesis sites and multiple receptors, represent likely research candidates for novel therapeutic targets. The present review summarises the available preclinical and human evidence regarding the neuropeptide, oxytocin, and its implications in the aetiology and treatment of MDD. While the evidence is not conclusive at present additional studies are warranted to determine whether OXT may be of therapeutic benefit in subsets of MDD patients such as those with comorbid anxiety symptoms and low levels of social attachment.

The clinical correlates of reported childhood sexual abuse: an association between age at trauma onset and severity of depression and PTSD in adults

This study investigated the relationship between the age of -self-reported sexual abuse occurrence and the development of post-traumatic stress disorder and/or depressive symptoms in adulthood. Subjects were evaluated for the presence of post-traumatic stress disorder and/or depressive symptoms as well as for a self-reported history of sexual abuse before the age of 18. Results found that relative risk of having severe post-traumatic stress disorder symptoms was 10 times higher in patients reporting sexual abuse after age 12 than in those reporting sexual abuse before age 12. Relative risk of having severe depressive symptoms was higher for those abused before the age of 12 than for those abused after the age of 12. Findings suggest that the impact of reported sexual abuse at different stages of development may lead to distinct psychiatric symptoms in adulthood.

Stress hormone regulation: biological role and translation into therapy

Stress is defined as a state of perturbed homeostasis following endangerment that evokes manifold adaptive reactions, which are summarized as the stress response. In the case of mental stress, the adaptive response follows the perception of endangerment. Different peptides, steroids, and biogenic amines operate the stress response within the brain and also after they have been released into circulation. We focus in this review on the biological roles of corticosteroids, corticotrophin-releasing hormone (CRH), and arginine vasopressin (AVP), and we evaluate the effects of treatments directed against the actions of these hormones. CRH and AVP are the central drivers of the stress hormone system, but they also act as neuromodulators in the brain, affecting higher mental functions including emotion, cognition, and behavior. When released toward the pituitary, these central neuropeptides elicit corticotrophin into the periphery, which activates corticosteroid release from the adrenal cortex. These stress hormones are essential for the adequate adaptation to stress, but they can also evoke severe clinical conditions once persistently hypersecreted. Depression and anxiety disorders are prominent examples of stress-related disorders associated with an impaired regulation of stress hormones. We summarize the effects of drugs acting at specific targets of the stress hormone axis, and we discuss their potential use as next-generation antidepressant medications. Such treatments require the identification of patients that will optimally benefit from such specific interventions. These could be a first step into personalized medicine using treatments tailored to the specific pathology of the patients.

Decreased numbers of progenitor cells but no response to antidepressant drugs in the hippocampus of elderly depressed patients

Imaging studies have consistently documented hippocampal volume reductions in depression. Although depressive disorders are traditionally considered to have a neurochemical basis, recent studies suggest that impairments of structural plasticity contribute to the volume reductions and the related cognitive changes. This might result from repeated periods of stress that are a wellknown risk factor for depression. Adult neurogenesis is a prominent example of neuroplasticity that in rodents, is reduced by stress but stimulated by antidepressant drugs. Although reductions in neurogenesis have been proposed to contribute to the etiology of depression, only two studies have so far examined hippocampal cytogenesis in depression, but this was in a limited number of subjects with considerable interindividual variation, and these studies came to different conclusions. We therefore collected hippocampal tissue of 10 elderly control subject and 10 well-matched depressed patients that were highly comparable in terms of age, sex, pH-CSF and postmortem delay, and tested whether the numbers of MCM2-positive progenitors and PH3-positive proliferating cells were altered by depression or antidepressant treatment. A significant reduction was found in MCM2-, but not PH3-immunopositive cells in depression. Although this result is consistent with the concept that structural plasticity is decreased in depression, we could not confirm that antidepressant drugs had a stimulatory effect on these cells. This discrepancy may relate to anatomical differences, in medication, to neurogenesis-independent mechanisms of antidepressant action, or the age of the patients that was higher than in previous studies. Whether the reduction is a cause or consequence of depression awaits to be determined.

Repeated brief postnatal maternal separation enhances hypothalamic gastric autonomic circuits in juvenile rats

Maternal separation of rat pups for 15 min each day over the first one to two postnatal weeks (MS15) has been shown to increase the active maternal care received by pups and to decrease their later neuroendocrine and behavioral stress reactivity compared to non-separated (NS) controls. Stress responses prominently feature altered gastric secretion and motility, and we previously reported that the developmental assembly of forebrain circuits underlying gastric autonomic control, including gastric responses to stress, is delayed by MS15 in neonatal rats [Card JP, Levitt P, Gluhovsky M, Rinaman L (2005) J Neurosci 25(40):9102-9111]. To determine how this early delay affects the later organization of central gastric autonomic circuits, the present study examined the effects of neonatal MS15 on central pre-gastric circuits assessed in post-weaning, juvenile rats. For this purpose, the retrograde transynaptic viral tracer, pseudorabies virus (PRV), was microinjected into the stomach wall of 28-30 day old male rats with an earlier developmental history of either MS15 or NS. Rats were perfused 72 h later and tissue was processed to reveal PRV-positive cells. Transynaptic PRV immunolabeling was quantified in selected preautonomic brainstem and forebrain regions, including the area postrema, bed nucleus of the stria terminalis, central nucleus of the amygdala, paraventricular nucleus of the hypothalamus (PVN), and visceral cortices. Compared to NS controls, MS15 rats displayed a significantly greater amount of PRV labeling within the PVN, including both the dorsal cap and ventral subnuclei. There were no postnatal group differences in the amount of PRV labeling within any other brain region examined in this study. This effect of MS15 to enhance hypothalamic preautonomic circuit structure indicates a strengthening of this pathway and may provide insight into how early life experience produces differential effects on later stress reactivity, including gastric secretory and motor responses to stress.

Compulsivity in mouse strains homologous with chromosomes 7p and 15q linked to obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a severe anxiety disorder characterized by obsessions and compulsions. The core symptom of OCD is compulsivity, the inability to stop thinking or acting when you want to, despite being aware of the uselessness of the content or the adverse consequences. To initiate a systematic search for genetic mechanisms underlying the pathophysiology of compulsivity, a panel of chromosome substitution (CS) strains, derived from mice that suppress (C57BL/6J strain) or maintain (A/J strain) high levels of repetitive wheel running during 2 hr of daily limited food access, was screened for this compulsive behavior. Following the genetic screen, we found linkage between compulsive wheel running and mouse chromosomes 2, 6, and 7 that show overlap with recently identified human linkage regions for OCD on chromosomes 7p and 15q. In the overlapping (human/mouse) genomic region, the CRH receptor 2 (CRHR2) gene was tested in a human case-control study. An initial exploration in OCD cases versus controls failed to detect an association between four-candidate CRH2R SNP's within this homologous linkage region and OCD. Genetic fine mapping of compulsivity in mice provides new opportunities to reveal mechanisms underlying this significant psychiatric trait.

The epigenetics of suicide: explaining the biological effects of early life environmental adversity

A number of recent studies have shown epigenetic alterations associated with suicidal behavior. These epigenetic mechanisms, which alter gene expression via alternative mechanisms to the coding DNA sequence, result from environmental effects acting on the genome. Studies in rodents indicate that variation in the early environment will trigger these epigenetic modifications and recent human data suggest the same may be true in humans.The expression of a number of genes, which are involved in normal brain functions and that have been shown to be under epigenetic control, seem to be dysregulated in suicide. The present review briefly describes the main epigenetic mechanisms involved in the regulation of gene expression and discusses recent findings of epigenetic alterations in suicidal behavior.

The differential impacts of early physical and sexual abuse and internalizing problems on daytime cortisol rhythm in school-aged children

The impact of early physical and sexual abuse (EPA/SA) occurring in the first 5 years of life was investigated in relation to depressive and internalizing symptomatology and diurnal cortisol regulation. In a summer camp context, school-aged maltreated (n = 265) and nonmaltreated (n = 288) children provided morning and late afternoon saliva samples on 5 consecutive days. Child self-report and adult observer reports of child internalizing and depressive symptoms were obtained. Children experiencing EPA/SA and high depressive or internalizing symptoms uniquely exhibited an attenuated diurnal decrease in cortisol, indicative of neuroendocrine dysregulation. These results were specific to EPA/SA rather than later onset physical or sexual abuse or early occurring neglect or emotional maltreatment.

Borderline personality disorder: hypothalamus pituitary adrenal axis and findings from neuroimaging studies

Borderline personality disorder (BPD) is a complex and serious mental disorder that is commonly seen psychiatric practice. Although stress, especially early life stress, seems to be associated with the development of the disorder, there has been far less research on the function of the hypothalamic-pituitary-adrenal (HPA) axis in BPD, compared to other psychiatric disorders, such as major depressive disorder and post-traumatic stress disorder. Stress has been suggested to exert damaging effects on the brain, particularly the hippocampus; therefore, neuroimaging studies yield important insight into the neurobiology of BPD. This article reviews research on the HPA axis and neuroimaging studies in BPD and aims to integrate these findings.

Vulnerability to stroke: implications of perinatal programming of the hypothalamic-pituitary-adrenal axis

Chronic stress is capable of exacerbating each major, modifiable, endogenous risk factor for cerebrovascular and cardiovascular disease. Indeed, exposure to stress can increase both the incidence and severity of stroke, presumably through activation of the hypothalamic-pituitary-adrenal (HPA) axis. Now that characterization of the mechanisms underlying epigenetic programming of the HPA axis is well underway, there has been renewed interest in examining the role of early environment on the evolution of health conditions across the entire lifespan. Indeed, neonatal manipulations in rodents that reduce stress responsivity, and subsequent life-time exposure to glucocorticoids, are associated with a reduction in the development of neuroendocrine, neuroanatomical, and cognitive dysfunctions that typically progress with age. Although improved day to day regulation of the HPA axis also may be accompanied by a decrease in stroke risk, evidence from rodent studies suggest that an associated cost could be increased susceptibility to inflammation and neuronal death in the event that a stroke does occur and the individual is exposed to persistently elevated corticosteroids. Given its importance in regulation of health and disease states, any long-term modulation of the HPA axis is likely to be associated with both benefits and potential risks. The goals of this review article are to examine (1) the clinical and experimental data suggesting that neonatal experiences can shape HPA axis regulation, (2) the influence of stress and the HPA axis on stroke incidence and severity, and (3) the potential for neonatal programming of the HPA axis to impact adult cerebrovascular health.

CRH signaling. Molecular specificity for drug targeting in the CNS

There is an urgent need to generate new drugs or improve existing ones in the pharmacology of mood disorders. The corticotropin-releasing hormone (CRH) system is closely involved in the development and course of depression, and drugs targeting this system arguably offer hope to improve the current tools for drug treatment of depression. Recent clinical studies in depressed patients showed that CRHR1 antagonists improve clinical symptoms of anxiety and depression and reduce stress hormone release following psychosocial stress. These effects of CRHR1 antagonists were not associated with reduced secretory capacity of corticotrophic cells because of CRH receptor abundance at the pituitary level, which contrasts with CRH receptors in the brain. This is in accordance with previous studies showing that CRH injections into the mouse brain activate MAPK pathways in a brain region-specific manner pointing toward differences in signaling pathways beyond the receptor level. We will highlight this and discuss how these brain area-specific differences may offer opportunities for drug discovery. An additional puzzle in the search of new targets for depression is the lack of bona fide animal models helping to discover the antidepressants that are not monoamine based. We recently developed a conditional mouse model that overexpresses CRH in a spatio-temporal-regulated fashion and permits to dissect precisely the contribution of different brain areas to the CRH-dependent behaviors. Recent findings obtained with this mouse model and its usefulness in the context of the CRH-dependent, region-specific changes in depression will be discussed.

Role of CRF receptor signaling in stress vulnerability, anxiety, and depression

Markers of hyperactive central corticotropin releasing factor (CRF) systems and CRF-related single nucleotide polymorphisms (SNPs) have been identified in patients with anxiety and depressive disorders. Designing more effective antagonists may now be guided by data showing that small molecules bind to transmembrane domains. Specifically, CRF(1) receptor antagonists have been developed as novel anxiolytic and antidepressant treatments. Because CRF(1) receptors become rapidly desensitized by G protein-coupled receptor kinase (GRK) and beta-arrestin mechanisms in the presence of high agonist concentrations, neuronal hypersecretion of synaptic CRF alone may be insufficient to account for excessive central CRF neurotransmission in stress-induced affective pathophysiology. In addition to desensitizing receptor function, GRK phosphorylation and beta-arrestin binding can shift a G protein-coupled receptor (GPCR) to signal selectively via the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) or Akt pathways independent of G proteins. Also, Epac-dependent CRF(1) receptor signaling via the ERK-MAPK pathway has been found to potentiate brain-derived neurotrophic factor (BDNF)-stimulated TrkB signaling. Thus, genetic or acquired abnormalities in GRK and beta-arrestin function may be involved in the pathophysiology of stress-induced anxiety and depression.

Behavioral and mental health challenges for indigenous youth: research and clinical perspectives for primary care

After first discussing historical, community and epidemiologic perspectives pertaining to mental health problems of Indigenous youth and families, this article reviews available research data on behavioral and mental health interventions and the roles that Native and Indigenous research programs are serving. Given the legacy of transgenerational trauma experienced by Indigenous peoples, community-based research and treatment methods are essential for solving these problems. The primary care provider stands in a unique position within the community to offer a "coinvestigator spirit" to youth and families in the pursuit of improving behavioral health. Strategies are presented for using the research literature, and collaborating with communities and families to help solve behavioral and mental health problems.