Childhood maltreatment, the corticotropin-releasing hormone receptor gene and adult depression in the general population

Gene environment interaction studies in depression and suicidal behavior: An update

Increasing evidence supports the involvement of both heritable and environmental risk factors in major depression (MD) and suicidal behavior (SB). Studies investigating gene-environment interaction (G × E) may be useful for elucidating the role of biological mechanisms in the risk for mental disorders. In the present paper, we review the literature regarding the interaction between genes modulating brain functions and stressful life events in the etiology of MD and SB and discuss their potential added benefit compared to genetic studies only. Within the context of G × E investigation, thus far, only a few reliable results have been obtained, although some genes have consistently shown interactive effects with environmental risk in MD and, to a lesser extent, in SB. Further investigation is required to disentangle the direct and mediated effects that are common or specific to MD and SB. Since traditional G × E studies overall suffer from important methodological limitations, further effort is required to develop novel methodological strategies with an interdisciplinary approach.

Translating the evidence for gene association with depression into mouse models of depression-relevant behaviour: current limitations and future potential

Depression is characterised by high prevalence and complex, heterogeneous psychopathology. At the level of aetio-pathology, considerable research effort has been invested to identify specific gene polymorphisms associated with increased depression prevalence. Genome-wide association studies have not identified any risk polymorphisms, and candidate gene case-control studies have identified a small number of risk polymorphisms. It is increasingly recognised that interaction between genotype and environmental factors (G×E), notably stressful life events, is the more realistic unit of depression aetio-pathology, with G×E evidence described for a small number of risk polymorphisms. An important complementary approach has been to describe genes exhibiting brain region-specific expression changes in depression. Mouse models of depression informed by the human evidence allow for the study of causality, but to-date have also yielded limited insights into depression aetio-pathology. This review of the translational evidence integrates human and mouse research approaches and evidence. It also makes specific recommendations in terms of how future research in human and mouse should be designed in order to deliver evidence for depression aetio-pathology and thereby to inform the development of novel and improved antidepressant treatments.

Genetic association of FKBP5 and CRHR1 with cortisol response to acute psychosocial stress in healthy adults

RATIONALE

Chronic dysregulation of hypothalamus-pituitary-adrenal (HPA) axis activity is related to several neuropsychiatric disorders. Studies suggest that cortisol response to stress has a strong genetic etiology, and that FK506 binding protein 5 (FKBP5) and G-protein coupled type-I CRH receptor (CRHR1) are key proteins regulating response. Variations in the genes encoding these proteins, FKBP5 and CRHR1, have been associated with several neuropsychiatric disorders.

OBJECTIVES

We examined variation in these genes in relation to cortisol response to psychological stress in one of the largest Trier Social Stress Test (TSST) cohorts yet examined.

METHODS

A total of 368 healthy, young adults underwent the TSST. Salivary cortisol was measured at multiple time points before and after the stressor. Nine variants in FKBP5 and four in CRHR1 were assessed. Single marker analyses were conducted. Secondary analyses assessed haplotypes and interaction with stress-related variables.

RESULTS

The strongest association was for rs4713902 in FKBP5 with baseline cortisol (p dom = 0.0004). We also identified a male-specific effect of FKBP5 polymorphisms on peak response and response area under the curve (p = 0.0028 for rs3800374). In CRHR1, rs7209436, rs110402, and rs242924 were nominally associated with peak response (p rec = 0.0029-0.0047). We observed interactions between trait anxiety and rs7209436 and rs110402 in CRHR1 in association with baseline cortisol (p LRT = 0.0272 and p LRT = 0.0483, respectively).

CONCLUSIONS

We show association of variants in FKBP5 and CRHR1 with cortisol response to psychosocial stress. These variants were previously shown to be associated with neuropsychiatric disorders. These findings have implications for interindividual variation in HPA axis activity and potentially for the etiology of neuropsychiatric disorders.

Interactive effects of corticotropin-releasing hormone receptor 1 gene and childhood adversity on depressive symptoms in young adults: findings from a longitudinal study

Accumulating research suggests a moderating role for the corticotropin-releasing hormone receptor 1 gene (CRHR1) in the association between childhood adversity and adult depression. The present study aims to replicate recent findings using different genetic variants and measures of early adversity assessed both prospectively and retrospectively. Data were collected in the context of an ongoing epidemiological cohort study following the outcome of early risk factors from birth into adulthood. 300 participants (137 males, 163 females) were genotyped for four CRHR1 SNPs (rs7209436, rs110402, rs242924, and rs17689882) and completed the Beck Depression Inventory at ages 19, 22 and 23 years. Childhood adversity was assessed using the Childhood Trauma Questionnaire and by a standardized parent interview yielding an index of family adversity. Our results indicate that CRHR1 and childhood adversity interacted to predict depressive symptoms in young adults. Specifically, we found that the impact of childhood maltreatment on adult depressive symptoms was significantly higher in individuals (i) with two copies of the CRHR1 TAT haplotype, and (ii) homozygous for the G allele of rs17689882. The interaction was demonstrated for exposure to childhood maltreatment as assessed by retrospective self-report, but not to prospectively ascertain objective family adversity. The present study partially replicates recent findings of a CRHR1 by childhood adversity interaction with regard to adult depression highlighting the subjective characteristics of the environmental pathogen that is operative in this interaction.

Gender-specific association between childhood trauma and rheumatoid arthritis: a case-control study

OBJECTIVE

Rheumatoid arthritis (RA) has been associated with a variety of emotional stressors, but findings remain inconclusive if RA is related to childhood trauma, which is known to have long-lasting negative consequences for physical health decades into adulthood. We investigated the association between childhood trauma and RA by comparing histories of child abuse and neglect between RA patients and adults from the general population in a cross-sectional case-control study.

METHODS

331 patients with definite RA and 662 gender- and age-matched adults from the general population were administered the self-report Childhood Trauma Questionnaire (CTQ) for the assessment of emotional, physical and sexual abuse as well as emotional and physical neglect.

RESULTS

Adjusting for gender and current depression, RA patients scored significantly higher in all CTQ subscales apart from sexual abuse and physical neglect than the controls. Adjusted odds ratios for these types of childhood trauma were higher in the RA group than in controls ranging from 2.0 for emotional neglect (95% confidence interval [CI]: 1.4-3.0) to 2.6 for emotional abuse (95% CI: 1.4-4.7). Gender-specific analyses revealed basically the same pattern for women, but not for men.

CONCLUSION

Our findings suggest an association between childhood trauma and development of RA, particularly in women. This relationship may be mediated by dysregulations of neuro-endocrine-immune networks, but larger prospective studies are needed to clarify the association between early life stress and the risk for RA in genetically susceptible individuals.

Gene × environment interactions in the prediction of response to antidepressant treatment

Major depressive disorder (MDD) is responsible for an increasing individual and global health burden. Extensive research on the genetic disposition to develop MDD and to predict the response to antidepressant treatment has yet failed to identify strong genetic effects. The concept of gene × environment interaction takes into account that environmental factors have been identified as important components in the development of MDD and combines both, genetic predisposition and environmental exposure, to elucidate complex traits such as MDD. Here, we review the current research on gene × environment interactions with regard to the development of MDD as well as response to antidepressant treatment. We hypothesize that gene × environment interactions delineate specific biological subtypes of depression and that individuals with such pathophysiological distinct types of depression will likely respond to different treatments. The elucidation of gene × environment interactions may thus not only help to understand the pathophysiology of MDD but could also provide markers for a personalized antidepressant therapy.

Addiction and corticotropin-releasing hormone type 1 receptor antagonist medications

Derangements in corticotropin-releasing hormone (CRH) through its type 1 receptor (CRHR1) have been identified in many pathologic conditions. Preclinical models of addiction find that small-molecule antagonists of CRHR1 can limit induction, maintenance, and relapse to drugs of abuse. Neuropsychiatric clinical trials of CRHR1 antagonists have shown mixed efficacy; treatment of addictive disorders has not been established, but finding effective treatments for addictive disorders is critical. Establishing effectiveness for substance abuse treatment will require a different design approach than was used for depression and anxiety trials. Focusing on active versus passive outcome measures, such as resilience to external stressful stimuli, may provide signals in curbing craving and relapse. Study design should include measures of abstinence and drug exposure, but additional elements of stress prevention should also be incorporated. Agents that could provide preemptive protection from drug use and relapse are novel and untested. An understanding of the evolutionary significance of the stress system and preclinical models suggests that these agents may provide protection in this manner. Investigators designing future trials might refocus their understanding of addiction and treatment in this new direction.

HPA axis genes may modulate the effect of childhood adversities on decision-making in suicide attempters

Decision-making impairment is found in several neuropsychiatric disorders, including suicidal behavior, and has been shown to be modulated by genes. On the other hand, early trauma have/has been associated with poor mental health outcome in adulthood, in interaction with genetic factors, possibly through sustained alterations in the hypothalamic-pituitary-adrenal axis (HPA axis). Here, we aimed to investigate the effect of childhood trauma and its interaction with HPA-axis related genes on decision-making abilities in adulthood among a sample of suicide attempters. The Iowa Gambling Task (IGT) was used to assess decision-making in 218 patients with a history of suicide attempt. Participant fulfilled the Childhood Trauma Questionnaire to report traumatic childhood experiences. Patients were genotyped for single-nucleotide polymorphisms within CRHR1 and CRHR2 genes. Patients with a history of sexual abuse had significantly lower IGT scores than non-sexually abused individuals. Polymorphisms within CRHR1 and CRHR2 genes interacted with both childhood sexual abuse and emotional neglect to influence IGT performance. In conclusion, childhood sexual abuse and emotional neglect may have long-term effects on decision-making through an interaction with key HPA axis genes. Even if these results need to be replicated in other sample, impaired decision-making may thus be the dimension through which child maltreatment, in interaction with HPA axis related genes, may have a sustained negative impact on adult mental health.

Gene-environment interactions in major depressive disorder

Family, twin, and epidemiologic studies have suggested that both genes and environment are important risk factors for the development of major depressive disorder (MDD). In the absence of consistent and strong main genetic effects, numerous studies have supported gene-environment interactions in this disorder. While the impact of negative environmental factors, such as early life stress, traumatic experiences, and negative life events have been established as risk factors, they are not sufficient to predict MDD. This article will review evidence suggesting that genetic variants moderate the effects of adversities on the development of MDD, with a focus on the importance of careful characterization of the stressful life events as well as systemic and molecular mechanisms that potentially mediate these gene-environment interactions.

Stress-related depression: neuroendocrine, genetic, and therapeutical aspects

OBJECTIVE

To summarize current concepts on neuroendocrine and genetic principles underlying stress-related depression and to discuss the challenges of personalized treatment in depression.

METHODS

Review of the literature pertaining to genetic and neuroendocrine basis of stress-related depression including aspects of treatment response with a focus on the hypothalamus-pituitary-adrenal (HPA) axis.

RESULTS

There is increasing evidence that genetic polymorphisms and dysregulation of the HPA axis are associated with the pathophysiology of stress-related depression. Individual stress hormone reactivity seems to be determined by a combination of genetic and environmental factors, contributing to both, resilience or vulnerability.

CONCLUSIONS

Although substantial progress has been made, current knowledge is still limited. Further basic and clinical research is needed to identify specific subgroups and to minimize heterogeneity of the depression phenotype. A better characterization is essential to detect genetic and functional predictors of antidepressant treatment response to follow the vision of personalized therapy in psychiatry.

Brain activation during fear conditioning in humans depends on genetic variations related to functioning of the hypothalamic-pituitary-adrenal axis: first evidence from two independent subsamples

BACKGROUND

Enhanced acquisition and delayed extinction of fear conditioning are viewed as major determinants of anxiety disorders, which are often characterized by a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis.

METHOD

In this study we employed cued fear conditioning in two independent samples of healthy subjects (sample 1: n=60, sample 2: n=52). Two graphical shapes served as conditioned stimuli and painful electrical stimulation as the unconditioned stimulus. In addition, guided by findings from published animal studies on HPA axis-related genes in fear conditioning, we examined variants of the glucocorticoid receptor and corticotropin-releasing hormone receptor 1 genes.

RESULTS

Variation in these genes showed enhanced amygdala activation during the acquisition and reduced prefrontal activation during the extinction of fear as well as altered amygdala-prefrontal connectivity.

CONCLUSIONS

This is the first demonstration of the involvement of genes related to the HPA axis in human fear conditioning.

Behavioral Studies and Genetic Alterations in Corticotropin-Releasing Hormone (CRH) Neurocircuitry: Insights into Human Psychiatric Disorders

To maintain well-being, all organisms require the ability to re-establish homeostasis in the presence of adverse physiological or psychological experiences. The regulation of the hypothalamic-pituitary adrenal (HPA) axis during stress is important in preventing maladaptive responses that may increase susceptibility to affective disorders. Corticotropin-releasing hormone (CRH) is a central stress hormone in the HPA axis pathway and has been implicated in stress-induced psychiatric disorders, reproductive and cardiac function, as well as energy metabolism. In the context of psychiatric disorders, CRH dysfunction is associated with the occurrence of post-traumatic stress disorder, major depression, anorexia nervosa, and anxiety disorders. Here, we review the synthesis, molecular signaling and regulation, as well as synaptic activity of CRH. We go on to summarize studies of altered CRH signaling in mutant animal models. This assembled data demonstrate an important role for CRH in neuroendocrine, autonomic, and behavioral correlates of adaptation and maladaptation. Next, we present findings regarding human genetic polymorphisms in CRH pathway genes that are associated with stress and psychiatric disorders. Finally, we discuss a role for regulators of CRH activity as potential sites for therapeutic intervention aimed at treating maladaptive behaviors associated with stress.

Association of CRHR1 and CRHR2 with major depressive disorder and panic disorder in a Japanese population

Major depressive disorder (MDD) and panic disorder (PD) are common and disabling medical disorders with stress and genetic components. Dysregulation of the stress response of the hypothalamic-pituitary-adrenal axis, including the corticotrophin-releasing hormone (CRH) signaling via primary receptors (CRHR1 and CRHR2), is considered to play a major role for onset and recurrence in MDD and PD. To confirm the association of CRHR1 and CRHR2 with MDD and PD, we investigated 12 single nucleotide polymorphisms (SNPs) (rs4076452, rs7209436, rs110402, rs242924, rs242940, and rs173365 for CRHR1 and rs4722999, rs3779250, rs2267710, rs1076292, rs2284217, and rs226771 for CRHR2) in MDD patients (n = 173), PD patients (n = 180), and healthy controls (n = 285). The SNP rs110402 and rs242924 in the CRHR1 gene and the rs3779250 in the CRHR2 gene were associated with MDD. The SNP rs242924 in the CRHR1 gene was also associated with PD. The T-A-T-G-G haplotype consisting of rs7209436 and rs173365 in CRHR1 was positively associated with MDD. The T-A haplotype consisting of rs7209436 and rs110402 in CRHR1 was positively associated with MDD. The C-C haplotype consisting of rs4722999 and rs37790 in CRHR1 was associated with PD. These results provide support for an association of CRHR1 and CRHR2 with MDD and PD.

Neuropeptide receptor ligands as drugs for psychiatric diseases: the end of the beginning?

The search for novel drugs for treating psychiatric disorders is driven by the growing medical need to improve on the effectiveness and side-effect profile of currently available therapies. Given the wealth of preclinical data supporting the role of neuropeptides in modulating behaviour, pharmaceutical companies have been attempting to target neuropeptide receptors for over two decades. However, clinical studies with synthetic neuropeptide ligands have been unable to confirm the promise predicted by studies in animal models. Here, we analyse preclinical and clinical results for neuropeptide receptor ligands that have been studied in clinical trials for psychiatric diseases, including agents that target the receptors for tachykinins, corticotropin-releasing factor, vasopressin and neurotensin, and suggest new ways to exploit the full potential of these candidate drugs.

Variation in the corticotropin-releasing hormone receptor 1 (CRHR1) gene influences fMRI signal responses during emotional stimulus processing

The corticotropin-releasing hormone (CRH) system coordinates neuroendocrine and behavioral responses to stress and has been implicated in the development of major depressive disorder (MDD). Recent reports suggest that GG-homozygous individuals of a single nucleotide polymorphism (rs110402) in the CRH receptor 1 (CRHR1) gene show behavioral and neuroendocrine evidence of stress vulnerability. The present study explores whether those observations extend to the neuronal processing of emotional stimuli in humans. CRHR1 was genotyped in 83 controls and a preliminary sample of 16 unmedicated patients with MDD who completed a functional magnetic resonance imaging scan while viewing blocks of positive, negative, and neutral words. In addition, potential mediating factors such as early life stress, sex, personality traits, and negative memory bias were examined. Robust differences in blood oxygenation level-dependent (BOLD) signal were found in healthy controls (A allele carriers > GG-homozygotes) in the right middle temporal/angular gyrus while subjects were viewing negative versus neutral words. Among GG-homozygotes, BOLD signal in the subgenual cingulate was greater in MDD participants (n = 9) compared with controls (n = 33). Conversely, among A-carriers, BOLD signal was smaller in MDD (n = 7) compared with controls (n = 50) in the hypothalamus, bilateral amygdala, and left nucleus accumbens. Early life stress, personality traits, and levels of negative memory bias were associated with brain activity depending on genotype. Results from healthy controls and a preliminary sample of MDD participants show that CRHR1 single nucleotide polymorphism rs110402 moderates neural responses to emotional stimuli, suggesting a potential mechanism of vulnerability for the development of MDD.

Childhood trauma in multiple sclerosis: a case-control study

OBJECTIVE

To investigate the association between childhood trauma and multiple sclerosis (MS) by comparing histories of child abuse and neglect between patients with MS and adults from the general population in a cross-sectional case-control study. Previous research has demonstrated a connection between MS and a variety of emotional stressors, but childhood trauma, which is known to have long-lasting negative consequences for physical health decades into adulthood, has not been studied.

METHODS

The self-reported Childhood Trauma Questionnaire for the assessment of emotional, physical, and sexual abuse and emotional and physical neglect was administered to 234 patients with definite MS and 885 adults from the general population.

RESULTS

After adjusting for sociodemographic factors and current depression, patients with MS scored significantly higher in all Childhood Trauma Questionnaire subscales apart from physical abuse and neglect than adults from the general population. Adjusted odds ratios for these types of childhood trauma were higher in the MS group than in controls, ranging from 2.0 for emotional neglect (95% confidence interval = 1.3-3.2) to 3.4 for emotional abuse (95% confidence interval = 2.0-5.7). Although childhood trauma was not associated with the degree of current MS-related disability, patients with MS with histories of physical and/or sexual abuse had significantly higher relapse rates than patients without early-life stress.

CONCLUSIONS

Our findings suggest an association between childhood trauma and MS in this cross-sectional study. Larger prospective longitudinal studies are needed to clarify the relationship between early-life stress and the risk for MS in genetically susceptible individuals.

A CRHR1 haplotype moderates the effect of adverse childhood experiences on lifetime risk of major depressive episode in African-American women

Adverse childhood experiences (ACEs) increase the risk for adult depression and substance dependence, possibly mediated by the corticotropin-releasing hormone type 1 receptor (CRHR1). In some studies, a three-SNP "T-A-T" haplotype in CRHR1, which encodes CRHR1, exerted a protective moderating effect on risk of depression in adults with ACEs. Other studies have shown a main or moderating effect of SNPs in CRHR1 on alcohol consumption. We tested the moderating effects of the three-SNP haplotype on lifetime risk of a major depressive episode (MDE) and alcohol dependence (AD) in 1,211 European-Americans (EAs) and 1,869 African-Americans (AAs), most of whom had a lifetime substance use disorder. There were no significant main or interaction effects of the TAT haplotype on AD. There was a significant interaction of ACE by TAT on risk of depression only in AA women (P = 0.005); each copy of the TAT haplotype reduced the odds of MDE by almost 40% (OR = 0.63). In AA women without an ACE and two TAT haplotypes, the risk of MDE was increased (OR = 1.51 for each copy). Our findings in relation to the TAT haplotype of CRHR1 extend those obtained in other populations to a largely substance-dependent one. The complex structure of CRHR1 may help to explain why some variants in the gene moderate the effects of an ACE only on depression risk while others moderate the effect of an ACE only on AD risk.

Current research trends in early life stress and depression: review of human studies on sensitive periods, gene-environment interactions, and epigenetics

Early life stress, such as childhood abuse, neglect and loss, is a well established major risk factor for developing depressive disorders later in life. We here summarize and discuss current developments in human research regarding the link between early life stress and depression. Specifically, we review the evidence for the existence of sensitive periods for the adverse effects of early life stress in humans. We further review the current state of knowledge regarding gene×environment (G×E) interactions in the effects of early life stress. While multiple genes operate in multiple environments to induce risk for depression after early life stress, these same genes also seem to enhance the beneficial effects of a positive early environment. Also, we discuss the epigenetic mechanisms that might underlie these G×E interactions. Finally, we discuss the potential importance of identifying sensitive time periods of opportunity, as well as G×E interactions and epigenetic mechanisms, for early interventions that might prevent or reverse the detrimental outcomes of early life stress and its transmission across generations.

Interactive effects of corticotropin releasing hormone receptor 1, serotonin transporter linked polymorphic region, and child maltreatment on diurnal cortisol regulation and internalizing symptomatology

Within an allostatic load framework, the effect of Gene × Environment (G × E) interactions on diurnal cortisol regulation and internalizing symptomatology were investigated. Variation in the corticotropin releasing hormone receptor 1 (CRHR1) TAT haplotype and serotonin transporter linked polymorphic region (5-HTTLPR) was determined in a sample of maltreated (n = 238, 21.4% with early physical and sexual abuse) and nonmaltreated (n = 255) children (M age = 10.08) participating in a summer research camp. Internalizing and depressive symptoms were assessed by other and self-report. G × E effects for CRHR1 and maltreatment and early abuse on diurnal cortisol regulation were observed; CRHR1 variation was related to cortisol dysregulation only among maltreated children. Early abuse and high internalizing symptoms also interacted to predict atypical diurnal cortisol regulation. The interaction of CRHR1, 5-HTTLPR, and child maltreatment (G × G × E) identified a subgroup of maltreated children with high internalizing symptoms who shared the same combination of the two genes. The findings support an allostatic load perspective on the effects of the chronic stress associated with child maltreatment on cortisol regulation and internalizing symptomatology as moderated by genetic variation.

Gene × environment vulnerability factors for PTSD: the HPA-axis

Post-traumatic stress disorder (PTSD) is a severely debilitating psychiatric condition. Although a lifetime trauma incidence of 40-90% has been reported in the general population, the overall lifetime prevalence for PTSD ranges between 7-12%, suggesting individual-specific differences towards the susceptibility to PTSD. While studies investigating main genetic effects associated with PTSD have yielded inconsistent findings, there is growing evidence supporting the role of gene-environment (G × E) interactions in PTSD. The hypothalamus pituitary adrenal (HPA) axis is one of the main systems activated after exposure to a trauma and perturbations in this system are one of the more consistent neurobiological abnormalities observed in PTSD. Genes regulating the HPA-axis are therefore interesting candidates for G × E studies in PTSD. This article will review the concept and initial results of G × E interactions with polymorphisms in these genes for PTSD. In addition, the use of alternate phenotypes and more complex interaction models such as G × G × E or G × E × E will be explored. Finally, putative molecular mechanisms for these interactions will be presented. The research presented in this article indicates that a combined analysis of environmental, genetic, endophenotype and epigenetic data will be necessary to better understand pathomechanisms in PTSD. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Using gene-environment interactions to target personalized treatment in mood disorder

Mood disorders account for a substantial social and financial burden on society. Although considerable efforts to delineate the underlying pathophysiological pathways have been undertaken during the last decades, only very limited progress on diagnostic and treatment algorithms have been achieved. High hopes have been put into genetics research to elucidate the pathogenesis of mood disorders, but so far, only small and inconsistent associations could be reported. Epidemiologic and family studies have always emphasized the importance of environmental factors; especially the impact of childhood trauma in mood disorders and more recently a number of specific gene-environment interactions have been reported. It is thus likely that the combination of a patient's life history and genetic susceptibility as well as other laboratory markers might provide a better insight into mental diseases and their treatment options. In this article, we discuss the concept of gene-environment interactions in major depression and their putative role in treatment response and personalized therapy.