Association of polymorphisms in genes regulating the corticotropin-releasing factor system with antidepressant treatment response

Research hotspots and trends in the relationship between genetics and major depressive disorder: A scientometric analysis from 2003 to 2023

To determine current research objectives and predict future trends in studies on the relationship between genetics and major depressive disorder (MDD). We collected the publications in the last 20 years (2003-2023) related to genetics and MDD in the Web of Science database, and applied Citespace to assess the knowledge mapping. The number of manuscripts about genetics and MDD totaled 9200, with a faster increase after 2013. The country, institution, and author with the most publications are the USA, the University of London, and Serretti, Alessandro. BIOL PSYCHIAT published the most articles in this field. In addition, the most co-cited reference is Sullivan PF (2000) (673). Genetic and MDD research, including the hippocampus, and HPA axis may become the focus of research in the future. Based on a 20-year scientometric investigation, we know the USA, China, and Germany have emerged as the important research forces in this discipline. The strongest collaborations between developed countries and renowned institutions are beneficial to the advancement of genetic and MDD research. Serotonin is the strongest citation bursts keyword.

Corticotropin-releasing factor signaling and its potential role in the prefrontal cortex-dependent regulation of anxiety

A large body of literature has highlighted the significance of the corticotropin-releasing factor (CRF) system in the regulation of neuropsychiatric diseases. Anxiety disorders are among the most common neuropsychiatric disorders. An increasing number of studies have demonstrated that the CRF family mediates and regulates the development and maintenance of anxiety. Thus, the CRF family is considered to be a potential target for the treatment of anxiety disorders. The prefrontal cortex (PFC) plays a role in the occurrence and development of anxiety, and both CRF and CRF-R1 are widely expressed in the PFC. This paper begins by reviewing CRF-related signaling pathways and their different roles in anxiety and related processes. Then, the role of the CRF system in other neuropsychiatric diseases is reviewed and the potential role of PFC CRF signaling in the regulation of anxiety disorders is discussed. Although other signaling pathways are potentially involved in the process of anxiety, CRF in the PFC primarily modulates anxiety disorders through the activation of corticotropin-releasing factor type1 receptors (CRF-R1) and the excitation of the cAMP/PKA signaling pathway. Moreover, the main signaling pathways of CRF involved in sex differentiation in the PFC appear to be different. In summary, this review suggests that the CRF system in the PFC plays a critical role in the occurrence of anxiety. Thus, CRF signaling is of great significance as a potential target for the treatment of stress-related disorders in the future.

Precision Medicine in Antidepressants Treatment

Precision medicine uses innovative approaches to improve disease prevention and treatment outcomes by taking into account people's genetic backgrounds, environments, and lifestyles. Treatment of depression is particularly challenging, given that 30-50% of patients do not respond adequately to antidepressants, while those who respond may experience unpleasant adverse drug reactions (ADRs) that decrease their quality of life and compliance. This chapter aims to present the available scientific data that focus on the impact of genetic variants on the efficacy and toxicity of antidepressants. We compiled data from candidate gene and genome-wide association studies that investigated associations between pharmacodynamic and pharmacokinetic genes and response to antidepressants regarding symptom improvement and ADRs. We also summarized the existing pharmacogenetic-based treatment guidelines for antidepressants, used to guide the selection of the right antidepressant and its dose based on the patient's genetic profile, aiming to achieve maximum efficacy and minimum toxicity. Finally, we reviewed the clinical implementation of pharmacogenomics studies focusing on patients on antidepressants. The available data demonstrate that precision medicine can increase the efficacy of antidepressants and reduce the occurrence of ADRs and ultimately improve patients' quality of life.

Body mass index interacts with a genetic-risk score for depression increasing the risk of the disease in high-susceptibility individuals

Depression is strongly associated with obesity among other chronic physical diseases. The latest mega- and meta-analysis of genome-wide association studies have identified multiple risk loci robustly associated with depression. In this study, we aimed to investigate whether a genetic-risk score (GRS) combining multiple depression risk single nucleotide polymorphisms (SNPs) might have utility in the prediction of this disorder in individuals with obesity. A total of 30 depression-associated SNPs were included in a GRS to predict the risk of depression in a large case-control sample from the Spanish PredictD-CCRT study, a national multicentre, randomized controlled trial, which included 104 cases of depression and 1546 controls. An unweighted GRS was calculated as a summation of the number of risk alleles for depression and incorporated into several logistic regression models with depression status as the main outcome. Constructed models were trained and evaluated in the whole recruited sample. Non-genetic-risk factors were combined with the GRS in several ways across the five predictive models in order to improve predictive ability. An enrichment functional analysis was finally conducted with the aim of providing a general understanding of the biological pathways mapped by analyzed SNPs. We found that an unweighted GRS based on 30 risk loci was significantly associated with a higher risk of depression. Although the GRS itself explained a small amount of variance of depression, we found a significant improvement in the prediction of depression after including some non-genetic-risk factors into the models. The highest predictive ability for depression was achieved when the model included an interaction term between the GRS and the body mass index (BMI), apart from the inclusion of classical demographic information as marginal terms (AUC = 0.71, 95% CI = [0.65, 0.76]). Functional analyses on the 30 SNPs composing the GRS revealed an over-representation of the mapped genes in signaling pathways involved in processes such as extracellular remodeling, proinflammatory regulatory mechanisms, and circadian rhythm alterations. Although the GRS on its own explained a small amount of variance of depression, a significant novel feature of this study is that including non-genetic-risk factors such as BMI together with a GRS came close to the conventional threshold for clinical utility used in ROC analysis and improves the prediction of depression. In this study, the highest predictive ability was achieved by the model combining the GRS and the BMI under an interaction term. Particularly, BMI was identified as a trigger-like risk factor for depression acting in a concerted way with the GRS component. This is an interesting finding since it suggests the existence of a risk overlap between both diseases, and the need for individual depression genetics-risk evaluation in subjects with obesity. This research has therefore potential clinical implications and set the basis for future research directions in exploring the link between depression and obesity-associated disorders. While it is likely that future genome-wide studies with large samples will detect novel genetic variants associated with depression, it seems clear that a combination of genetics and non-genetic information (such is the case of obesity status and other depression comorbidities) will still be needed for the optimization prediction of depression in high-susceptibility individuals.

Corticotropin Releasing Factor Binding Protein as a Novel Target to Restore Brain Homeostasis: Lessons Learned From Alcohol Use Disorder Research

Stress is well-known to contribute to the development of many psychiatric illnesses including alcohol and substance use disorder (AUD and SUD). The deleterious effects of stress have also been implicated in the acceleration of biological age, and age-related neurodegenerative disease. The physio-pathology of stress is regulated by the corticotropin-releasing factor (CRF) system, the upstream component of the hypothalamic-pituitary-adrenal (HPA) axis. Extensive literature has shown that dysregulation of the CRF neuroendocrine system contributes to escalation of alcohol consumption and, similarly, chronic alcohol consumption contributes to disruption of the stress system. The CRF system also represents the central switchboard for regulating homeostasis, and more recent studies have found that stress and aberrations in the CRF pathway are implicated in accelerated aging and age-related neurodegenerative disease. Corticotropin releasing factor binding protein (CRFBP) is a secreted glycoprotein distributed in peripheral tissues and in specific brain regions. It neutralizes the effects of CRF by sequestering free CRF, but may also possess excitatory function by interacting with CRF receptors. CRFBP’s dual role in influencing CRF bioavailability and CRF receptor signaling has been shown to have a major part in the HPA axis response. Therefore, CRFBP may represent a valuable target to treat stress-related illness, including: development of novel medications to treat AUD and restore homeostasis in the aging brain. This narrative review focuses on molecular mechanisms related to the role of CRFBP in the progression of addictive and psychiatric disorders, biological aging, and age-related neurodegenerative disease. We provide an overview of recent studies investigating modulation of this pathway as a potential therapeutic target for AUD and age-related neurodegenerative disease.

Barriers to clinical adoption of pharmacogenomic testing in psychiatry: a critical analysis

Pharmacogenomics (PGx) is the study of genetic influences on an individual's response to medications. Improvements in the quality and quantity of PGx research over the past two decades have enabled the establishment of commercial markets for PGx tests. Nevertheless, PGx testing has yet to be adopted as a routine practice in clinical care. Accordingly, policy regulating the commercialization and reimbursement of PGx testing is in its infancy. Several papers have been published on the topic of challenges, or 'barriers' to clinical adoption of this healthcare innovation. However, many do not include recent evidence from randomized controlled trials, economic utility studies, and qualitative assessments of stakeholder opinions. The present paper revisits the most cited barriers to adoption of PGx testing: evidence for clinical utility, evidence for economic effectiveness, and stakeholder awareness. We consider these barriers in the context of reviewing PGx literature published over the past two decades and emphasize data from commercial PGx testing companies, since they have published the largest datasets. We conclude with a discussion of existing limitations to PGx testing and recommendations for progress.

Interaction of FKBP5 variant rs3800373 and city living alters the neural stress response in the anterior cingulate cortex

Psychosocial stress effects of urban living are associated with substantially increased risk for schizophrenia, mood and anxiety disorders, by altering stress-induced activity in the amygdala and pregenual anterior cingulate cortex (ACC). Genetic factors are likely to modulate the impact of city living on stress processing. Growing evidence suggests a key role of FKBP5, a co-chaperone regulating the glucocorticoid receptor sensitivity, in the etiology of stress-related disorders. Here we investigated the interaction of city living and genetic variation in FKBP5 (rs3800373) on neural activity in stress-sensitive brain systems. Functional magnetic resonance imaging was performed in 31 healthy young adults using the Montreal Imaging Stress Task. Subjects were divided into groups depending on the number of inhabitants of their current residency. There was a significant main effect of city living on neural activity in the amygdala-hippocampus complex, replicating prior findings. Moreover, we found an interaction between rs3800373 and city living modulating responses in the bilateral subgenual ACC and right pregenual ACC. Specifically, only city dwellers carrying the FKBP5 minor risk allele showed increased stress responses in the subgenual and pregenual ACC when compared to those living in small towns. A significant gene-environment interaction on neural stress responses in the amygdala or hippocampus was only found in FKBP5 major allele carriers. These results point to a potential role of the FKBP5 rs3800373 minor risk allele in predisposing those who live in bigger cities to changes of functional responsivity in the pre- and subgenual ACC, thereby increasing the risk for developing stress-related mental disorders.

Corticotropin releasing hormone receptor CRHR1 gene is associated with tianeptine antidepressant response in a large sample of outpatients from real-life settings

Polymorphisms of genes involved in the hypothalamic-pituitary-adrenocortical (HPA) axis have been associated with response to several antidepressant treatments in patients suffering of depression. These pharmacogenetics findings have been reported from independent cohorts of patients mostly treated with selective serotonin reuptake inhibitors, tricyclic antidepressant, and mirtazapine. Tianeptine, an atypical antidepressant, recently identified as a mu opioid receptor agonist, which prevents and reverses the stress induced by glucocorticoids, has been investigated in this present pharmacogenetics study. More than 3200 Caucasian outpatients with a major depressive episode (MDE) from real-life settings were herein analyzed for clinical response to tianeptine, a treatment initiated from 79.5% of the subjects, during 6-8 weeks follow-up, assessing polymorphisms targeting four genes involved in the HPA axis (NR3C1, FKPB5, CRHR1, and AVPR1B). We found a significant association (p < 0.001) between CRHR1 gene variants rs878886 and rs16940665, or haplotype rs878886*C-rs16940665*T, and tianeptine antidepressant response and remission according to the hospital anxiety and depression scale. Analyses, including a structural equation model with simple mediation, suggest a moderate effect of sociodemographic characteristics and depressive disorder features on treatment response in individuals carrying the antidepressant responder allele rs8788861 (allele C). These findings suggest direct pharmacological consequences of CRHR1 polymorphisms in the antidepressant tianeptine response and remission, in MDE patients. This study replicates the association of the CRHR1 gene, involved in the HPA axis, with (1) a specificity attributed to treatment response, (2) a lower risk of chance finding, and in (3) an ecological situation.

Corticotropin-releasing factor receptor signaling and modulation: implications for stress response and resilience

Introduction In addition to their role in regulation of the hypothalamic-pituitary-adrenal-axis, corticotropin-releasing factor (CRF) and its related peptides, the urocortins, are important mediators of physiological and pathophysiological processes of the central nervous, cardiovascular, gastrointestinal, immune, endocrine, reproductive, and skin systems. Altered regulation of CRF-mediated adaptive responses to various stressful stimuli disrupts healthy function and might confer vulnerability to several disorders, including depression and anxiety. Methodology This narrative review was conducted through search and analysis of studies retrieved from online databases using a snowball method. Results This review covers aspects beginning with the discovery of CRF, CRF binding protein and their actions via interaction with CRF receptors type 1 and type 2. These are surface plasma membrane receptors, activation of which is associated with conformational changes and interaction with a variety of G-proteins and signaling pathways. We also reviewed the pharmacology and mechanisms of the receptor signaling modulatory activity of these receptors. Conclusion This review compiles and presents knowledge regarding the CRFergic system, including CRF related peptides, CRF binding protein, and CRF receptors, as well as some evidence that is potentially indicative of the biological roles of these entities in several physiological and pathophysiological processes.

The GCAG Haplotype of the CRHBP Gene May Decrease the Risk for Robbery Behavior Among the Han Chinese

Aims: Hypothalamic-pituitary-adrenocortical axis gene polymorphisms have been reported to affect aggressive behavior. Corticotropin releasing hormone binding protein (CRHBP) polymorphisms have been shown to contribute to the susceptibility to stress-related disorders, including aggressive behavior. However, no study has been conducted on the relationship between CRHBP polymorphisms and aggressive behavior risk in the Han Chinese population. Methods: A case-control study that comprised 194 male criminals and 303 healthy controls was carried out to investigate the genetic association between several CRHBP gene polymorphisms and aggressive behavior risk in the Hunan Han population. Genotyping was conducted by using the improved multiplex ligase detection reaction method for four CRHBP loci: rs10062367, rs32897, rs7718461, and rs7721799. Results: The incidence of the rs32897C allele was significantly lower in the robbery group compared with the control subjects after a Bonferroni correction (p = 0.016), indicating a protective role for the C allele of rs32897. Interestingly, a haplotypic analysis that was stratified by robbery and intentional injury showed that the haplotype consisting of rs10062367G, rs32897C, rs7718461A, and rs7721799G (which includes the protective rs32897 C allele) was significantly associated with decreased robbery risk (odds ratio [OR] = 0.31, p = 0.0005), but not for intentional injury (OR = 0.82, p = 0.44). The haplotype consisting of rs10062367G, rs32897T, rs7718461A, and rs7721799G carrying the rs32897 T allele significantly increased the risk for robbery (OR = 1.47, p = 0.0213), but not for intentional injury (OR = 0.92, p = 0.64). Conclusions: The rs32897 alleles and the haplotypes containing the rs32897 alleles, including GCAG and GTAG, may be factors associated with committing robbery in the Hunan Han population, and could be used to provide clinical counseling with regard to aggressive behavior. However, further studies including multiple ethnicities are needed.

A review of clinical pharmacogenetics Studies in African populations

Effective interventions and treatments for complex diseases have been implemented globally, however, coverage in Africa has been comparatively lower due to lack of capacity, clinical applicability and knowledge on the genetic contribution to disease and treatment. Currently, there is a scarcity of genetic data on African populations, which have enormous genetic diversity. Pharmacogenomics studies have the potential to revolutionise treatment of diseases, therefore, African populations are likely to benefit from these approaches to identify likely responders, reduce adverse side effects and optimise drug dosing. This review discusses clinical pharmacogenetics studies conducted in African populations, focusing on studies that examined drug response in complex diseases relevant to healthcare. Several pharmacogenetics associations have emerged from African studies, as have gaps in knowledge.

Systems Approach to Identify Common Genes and Pathways Associated with Response to Selective Serotonin Reuptake Inhibitors and Major Depression Risk

Despite numerous studies on major depressive disorder (MDD) susceptibility, the precise underlying molecular mechanism has not been elucidated which restricts the development of etiology-based disease-modifying drug. Major depressive disorder treatment is still symptomatic and is the leading cause of (~30%) failure of the current antidepressant therapy. Here we comprehended the probable genes and pathways commonly associated with antidepressant response and MDD. A systematic review was conducted, and candidate genes/pathways associated with antidepressant response and MDD were identified using an integrative genetics approach. Initially, single nucleotide polymorphisms (SNPs)/genes found to be significantly associated with antidepressant response were systematically reviewed and retrieved from the candidate studies and genome-wide association studies (GWAS). Also, significant variations concerning MDD susceptibility were extracted from GWAS only. We found 245 (Set A) and 800 (Set B) significantly associated genes with antidepressant response and MDD, respectively. Further, gene set enrichment analysis revealed the top five co-occurring molecular pathways (p ≤ 0.05) among the two sets of genes: Cushing syndrome, Axon guidance, cAMP signaling pathway, Insulin secretion, and Glutamatergic synapse, wherein all show a very close relation to synaptic plasticity. Integrative analyses of candidate gene and genome-wide association studies would enable us to investigate the putative targets for the development of disease etiology-based antidepressant that might be more promising than current ones.

Childhood trauma dependent anxious depression sensitizes HPA axis function

Anxious depression is a common subtype of major depressive disorder (MDD) and is associated with greater severity and poorer outcome. Alterations of the hypothalamic-pituitary-adrenal (HPA) axis, especially of the glucocorticoid receptor (GR) function, are often observed in MDD, but evidence lacks for anxious depression. Childhood adversity is known to influence both the HPA axis and risk of MDD. Therefore, we investigated GR-function in anxious depression dependent on childhood adversity. We enrolled 144 depressed in-patients (49.3% females). Anxious depression was defined using the Hamilton Depression Rating Scale (HAM-D) anxiety/somatization factor score ≥7. Blood draws were performed at 6 pm before and 3 h after 1.5 mg dexamethasone ingestion for measurement of cortisol, ACTH and blood count to assess GR-function and the immune system. In a subgroup of n = 60 FKBP5 mRNA controlled for FKBP5 genotype was measured before and after dexamethasone. Childhood adversity was evaluated using the Childhood Trauma Questionnaire (CTQ). We identified 78 patients (54.2%) with anxious depression who showed a greater severity and worse outcome. These patients were more often exposed to sexual abuse (30% vs. 16%/p = 0.04) and emotional neglect (76% vs. 58%/p = 0.02) than patients with non-anxious depression. Anxious depressed patients showed an enhanced GR-induced FKBP5 mRNA expression (F = 5.128; p = 0.03) and reduced cortisol levels, partly dependent on sexual abuse (F = 7.730; p = 0.006). Additionally, the GR-induced leukocyte response was enhanced in patients with sexual abuse (F = 7.176; p = 0.008). Anxious depression in dependence of childhood trauma is associated with heightened sensitivity of the HPA axis and the immune system which should be considered for treatment algorithms and targets.

Polymorphisms in genes related to the hypothalamic-pituitary-adrenal axis and antidepressant response - Systematic review

OBJECTIVE

Around 50% of depressed patients do not respond to antidepressants. Evidence from familial studies suggests a genetic component to this. This study investigated whether patients with polymorphisms in genes related to the hypothalamic-pituitary-adrenal (HPA) axis were less likely to respond to antidepressants.

METHOD

EMBASE, MEDLINE, PsycINFO, and the Cochrane Library were searched. Inclusionary criteria were: 1) patients with depression, 2) study of HPA axis-related candidate genes, 3) at least four weeks of antidepressants, and 4) assessment of depressive symptoms dividing patients into non-responders and responders.

RESULTS

Nineteen studies were identified. Non-responders and responders did not differ in single nucleotide polymorphisms (SNPs) in genes encoding arginine vasopressin. Findings were equivocal regarding genes encoding the FK506 binding protein 5 and glucocorticoid and mineralocorticoid receptors. Specific SNPs and haplotypes within genes related to corticotropin-releasing hormone (CRHBP, CRHR1) and melanocortins (POMC) predicted non-responder status.

CONCLUSIONS

Replication studies and additional investigations exploring gene x environment and drug x environment interactions are necessary before pharmacological treatments may be adjusted based on a patient's genetic profile.

The Corticotropin-Releasing Factor Family: Physiology of the Stress Response

The physiological stress response is responsible for the maintenance of homeostasis in the presence of real or perceived challenges. In this function, the brain activates adaptive responses that involve numerous neural circuits and effector molecules to adapt to the current and future demands. A maladaptive stress response has been linked to the etiology of a variety of disorders, such as anxiety and mood disorders, eating disorders, and the metabolic syndrome. The neuropeptide corticotropin-releasing factor (CRF) and its relatives, the urocortins 1–3, in concert with their receptors (CRFR1, CRFR2), have emerged as central components of the physiological stress response. This central peptidergic system impinges on a broad spectrum of physiological processes that are the basis for successful adaptation and concomitantly integrate autonomic, neuroendocrine, and behavioral stress responses. This review focuses on the physiology of CRF-related peptides and their cognate receptors with the aim of providing a comprehensive up-to-date overview of the field. We describe the major molecular features covering aspects of gene expression and regulation, structural properties, and molecular interactions, as well as mechanisms of signal transduction and their surveillance. In addition, we discuss the large body of published experimental studies focusing on state-of-the-art genetic approaches with high temporal and spatial precision, which collectively aimed to dissect the contribution of CRF-related ligands and receptors to different levels of the stress response. We discuss the controversies in the field and unravel knowledge gaps that might pave the way for future research directions and open up novel opportunities for therapeutic intervention.

Association between stress pathway gene (CRHR1⧹CRHBP) polymorphisms and heroin dependence

Stress could increase risk of heroin addiction and relapse. Genetic factors that associated with stress may be involved in this process. To explore the relationship between stress pathway gene (CRHR1⧹CRHBP) polymorphisms and heroin dependence, nine tag single nucleotide polymorphisms (CRHR1 rs12953076, rs4458044, rs242924, rs17689966; CRHBP rs1715751, rs3792738, rs32897, rs10062367, rs1875999) of stress related genes were genotyped by TaqMan SNP genotyping assay for 524 heroin-dependent patients who were abstinent and 489 normal controls. The patients were followed up for 5 years to determine whether relapse or not. Life stress was assessed by Perceived Stress Scale (PSS) at baseline and within 12 months just discharged. No differences were found in the frequencies of genotypes and alleles in nine loci of stress pathway genes between case and control groups (p > 0.05), but there were significant discrepancy in perceived stress scores in genotype distributions. Multivariate regression analysis revealed that CRHBP gene polymorphism rs3792738 had interactions with life stress during predicting the risk of heroin relapse. It was concluded that the predictive value of a genetic interaction with the stress axis for the risk of heroin relapse may be useful for future preventive and individualized therapeutic strategies.

Antidepressant Outcomes Predicted by Genetic Variation in Corticotropin-Releasing Hormone Binding Protein

OBJECTIVE

Genetic variation within the hypothalamic-pituitary-adrenal (HPA) axis has been linked to risk for depression and antidepressant response. However, these associations have yet to produce clinical gains that inform treatment decisions. The authors investigated whether variation within HPA axis genes predicts antidepressant outcomes within two large clinical trials.

METHOD

The test sample comprised 636 patients from the International Study to Predict Optimized Treatment in Depression (iSPOT-D) who completed baseline and 8-week follow-up visits and for whom complete genotyping data were available. The authors tested the relationship between genotype at 16 candidate HPA axis single-nucleotide polymorphisms (SNPs) and treatment outcomes for three commonly used antidepressants (escitalopram, sertraline, and extended-release venlafaxine), using multivariable linear and logistic regression with Bonferroni correction. Response and remission were defined using the Hamilton Depression Rating Scale. Findings were then validated using the Predictors of Remission in Depression to Individual and Combined Treatments (PReDICT) study of outcome predictors in treatment-naive patients with major depression.

RESULTS

The authors found that the rs28365143 variant within the corticotropin-releasing hormone binding protein (CRHBP) gene predicted antidepressant outcomes for remission, response, and symptom change. Patients homozygous for the G allele of rs28365143 had greater remission rates, response rates, and symptom reductions. These effects were specific to drug class. Patients homozygous for the G allele responded significantly better to the selective serotonin reuptake inhibitors escitalopram and sertraline than did A allele carriers. In contrast, rs28365143 genotype was not associated with treatment outcomes for the serotonin norepinephrine reuptake inhibitor venlafaxine. When patients were stratified by race, the overall effect of genotype on treatment response remained. In the validation sample, the GG genotype was again associated with favorable antidepressant outcomes, with comparable effect sizes.

CONCLUSIONS

These findings suggest that a specific CRHBP SNP, rs28365143, may have a role in predicting which patients will improve with antidepressants and which type of antidepressant may be most effective. The results add to the foundational knowledge needed to advance a precision approach to personalized antidepressant choices.

Genetic variations in genes of the stress response pathway are associated with prolonged abstinence from heroin

AIM

This study assesses whether genetic variants in stress-related genes are associated with prolonged abstinence from heroin in subjects that are not in long-term methadone treatment.

METHODS

Frequencies of 117 polymorphisms in 30 genes were compared between subjects with history of heroin addiction, either without agonist treatment (n = 129) or in methadone maintenance treatment (n = 923).

RESULTS

SNP rs1500 downstream of CRHBP and an interaction of SNPs rs10482672 (NR3C1) and rs4234955 (NPY1R/NPY5R) were significantly associated with prolonged abstinence without agonist treatment.

CONCLUSION

This study suggests that variability in stress-related genes may contribute to the ability of certain subjects to remain in prolonged abstinence from heroin, possibly due to higher resilience to stress.

HPA-axis genes as potential risk variants for neurocognitive decline in trauma-exposed, HIV-positive females

PURPOSE

Previous studies have independently provided evidence for the effects of HIV infection, hypothalamic-pituitary-adrenal (HPA) axis dysfunction and early life trauma on neurocognitive impairment (NCI). This study examined the interaction between single-nucleotide polymorphisms (SNPs) of two HPA axis genes, corticotrophin-releasing hormone receptor 1 (CRHR1; rs110402, rs242924, rs7209436, and rs4792888) and corticotrophin-releasing hormone-binding protein (CRHBP; rs32897, rs10062367, and rs1053989), childhood trauma, and HIV-associated NCI.

PATIENTS AND METHODS

The sample comprised 128 HIV-positive Xhosa females of whom 88 (69%) had a history of childhood trauma. NCI was assessed using a battery of 17 measures sensitive to the effects of HIV, and the history of childhood trauma was assessed using the validated retrospective Childhood Trauma Questionnaire-Short Form. Generalized linear regression models were used to compare allelic distribution by trauma status and global NCI. The association between genotype, childhood trauma, and cognitive scores was also evaluated using generalized linear regression models, assuming additive models for the SNPs, and ANOVA.

RESULTS

Of the seven polymorphisms assessed, only the rs10062367 variant of CRHBP was significantly associated with global NCI (P=0.034), independent of childhood trauma. This polymorphism was not significantly associated with z-scores on any specific cognitive domain. The interaction of childhood trauma and variants of CRHR1 was associated with poorer learning (rs110402) and/or recall (rs110402 and rs4792888).

CONCLUSION

These findings suggest that CRHBP rs10062367 A allele is a possible risk variant for NCI in HIV, independent of childhood trauma. Furthermore, results show that the interaction of childhood trauma with variants of CRHR1, rs110402 and rs4792888, confer added vulnerability to NCI in HIV-infected individuals in cognitive domains that are known to be impacted by HIV. While these findings need independent replication in larger samples, it adds CRHBP and CRHR1 to the list of known genes linked to HIV- and childhood trauma-associated neurocognitive phenotypes.

Cell Type-Specific Expression of Corticotropin-Releasing Hormone-Binding Protein in GABAergic Interneurons in the Prefrontal Cortex

Corticotropin-releasing hormone-binding protein (CRH-BP) is a secreted glycoprotein that binds CRH with very high affinity to modulate CRH receptor activity. CRH-BP is widely expressed throughout the brain, with particularly high expression in regions such as the amygdala, hippocampus, ventral tegmental area and prefrontal cortex (PFC). Recent studies suggest a role for CRH-BP in stress-related psychiatric disorders and addiction, with the PFC being a potential site of interest. However, the molecular phenotype of CRH-BP-expressing cells in this region has not been well-characterized. In the current study, we sought to determine the cell type-specific expression of CRH-BP in the PFC to begin to define the neural circuits in which this key regulator is acting. To characterize the expression of CRH-BP in excitatory and/or inhibitory neurons, we utilized dual in situ hybridization to examine the cellular colocalization of CRH-BP mRNA with vesicular glutamate transporter (VGLUT) or glutamic acid decarboxylase (GAD) mRNA in different subregions of the PFC. We show that CRH-BP is expressed predominantly in GABAergic interneurons of the PFC, as revealed by the high degree of colocalization (>85%) between CRH-BP and GAD. To further characterize the expression of CRH-BP in this heterogenous group of inhibitory neurons, we examined the colocalization of CRH-BP with various molecular markers of GABAergic interneurons, including parvalbumin (PV), somatostatin (SST), vasoactive intestinal peptide (VIP) and cholecystokinin (CCK). We demonstrate that CRH-BP is colocalized predominantly with SST in the PFC, with lower levels of colocalization in PV- and CCK-expressing neurons. Our results provide a more comprehensive characterization of the cell type-specific expression of CRH-BP and begin to define its potential role within circuits of the PFC. These results will serve as the basis for future in vivo studies to manipulate CRH-BP in a cell type-specific manner to better understand its role in stress-related psychiatric disorders, including anxiety, depression and addiction.

Corticotropin-releasing hormone-binding protein and stress: from invertebrates to humans

Corticotropin-releasing hormone (CRH) is a key regulator of the stress response. This peptide controls the hypothalamic-pituitary-adrenal (HPA) axis as well as a variety of behavioral and autonomic stress responses via the two CRH receptors, CRH-R1 and CRH-R2. The CRH system also includes an evolutionarily conserved CRH-binding protein (CRH-BP), a secreted glycoprotein that binds CRH with subnanomolar affinity to modulate CRH receptor activity. In this review, we discuss the current literature on CRH-BP and stress across multiple species, from insects to humans. We describe the regulation of CRH-BP in response to stress, as well as genetic mouse models that have been utilized to elucidate the in vivo role(s) of CRH-BP in modulating the stress response. Finally, the role of CRH-BP in the human stress response is examined, including single nucleotide polymorphisms in the human CRHBP gene that are associated with stress-related affective disorders and addiction. Lay summary The stress response is controlled by corticotropin-releasing hormone (CRH), acting via CRH receptors. However, the CRH system also includes a unique CRH-binding protein (CRH-BP) that binds CRH with an affinity greater than the CRH receptors. In this review, we discuss the role of this highly conserved CRH-BP in regulation of the CRH-mediated stress response from invertebrates to humans.

Hypothalamic-pituitary-adrenal axis genetic variation and early stress moderates amygdala function

Early life stress may precipitate psychopathology, at least in part, by influencing amygdala function. Converging evidence across species suggests that links between childhood stress and amygdala function may be dependent upon hypothalamic-pituitary-adrenal (HPA) axis function. Using data from college-attending non-Hispanic European-Americans (n=308) who completed the Duke Neurogenetics Study, we examined whether early life stress (ELS) and HPA axis genetic variation interact to predict threat-related amygdala function as well as psychopathology symptoms. A biologically-informed multilocus profile score (BIMPS) captured HPA axis genetic variation (FKBP5 rs1360780, CRHR1 rs110402; NR3C2 rs5522/rs4635799) previously associated with its function (higher BIMPS are reflective of higher HPA axis activity). BOLD fMRI data were acquired while participants completed an emotional face matching task. ELS and depression and anxiety symptoms were measured using the childhood trauma questionnaire and the mood and anxiety symptom questionnaire, respectively. The interaction between HPA axis BIMPS and ELS was associated with right amygdala reactivity to threat-related stimuli, after accounting for multiple testing (empirical-p=0.016). Among individuals with higher BIMPS (i.e., the upper 21.4%), ELS was positively coupled with threat-related amygdala reactivity, which was absent among those with average or low BIMPS. Further, higher BIMPS were associated with greater self-reported anxious arousal, though there was no evidence that amygdala function mediated this relationship. Polygenic variation linked to HPA axis function may moderate the effects of early life stress on threat-related amygdala function and confer risk for anxiety symptomatology. However, what, if any, neural mechanisms may mediate the relationship between HPA axis BIMPS and anxiety symptomatology remains unclear.

Pharmacogenetics and Imaging-Pharmacogenetics of Antidepressant Response: Towards Translational Strategies

Genetic variation underlies both the response to antidepressant treatment and the occurrence of side effects. Over the past two decades, a number of pharmacogenetic variants, among these the SCL6A4, BDNF, FKBP5, GNB3, GRIK4, and ABCB1 genes, have come to the forefront in this regard. However, small effects sizes, mixed results in independent samples, and conflicting meta-analyses results led to inherent difficulties in the field of pharmacogenetics translating these findings into clinical practice. Nearly all antidepressant pharmacogenetic variants have potentially pleiotropic effects in which they are associated with major depressive disorder, intermediate phenotypes involved in emotional processes, and brain areas affected by antidepressant treatment. The purpose of this article is to provide a comprehensive review of the advances made in the field of pharmacogenetics of antidepressant efficacy and side effects, imaging findings of antidepressant response, and the latest results in the expanding field of imaging-pharmacogenetics studies. We suggest there is mounting evidence that genetic factors exert their impact on treatment response by influencing brain structural and functional changes during antidepressant treatment, and combining neuroimaging and genetic methods may be a more powerful way to detect biological mechanisms of response than either method alone. The most promising imaging-pharmacogenetics findings exist for the SCL6A4 gene, with converging associations with antidepressant response, frontolimbic predictors of affective symptoms, and normalization of frontolimbic activity following antidepressant treatment. More research is required before imaging-pharmacogenetics informed personalized medicine can be applied to antidepressant treatment; nevertheless, inroads have been made towards assessing genetic and neuroanatomical liability and potential clinical application.

Western High-Fat Diet Consumption during Adolescence Increases Susceptibility to Traumatic Stress while Selectively Disrupting Hippocampal and Ventricular Volumes

Psychological trauma and obesity co-occur frequently and have been identified as major risk factors for psychiatric disorders. Surprisingly, preclinical studies examining how obesity disrupts the ability of the brain to cope with psychological trauma are lacking. The objective of this study was to determine whether an obesogenic Western-like high-fat diet (WD) predisposes rats to post-traumatic stress responsivity. Adolescent Lewis rats (postnatal day 28) were fed ad libitum for 8 weeks with either the experimental WD diet (41.4% kcal from fat) or the control diet (16.5% kcal from fat). We modeled psychological trauma by exposing young adult rats to a cat odor threat. The elevated plus maze and the open field test revealed increased psychological trauma-induced anxiety-like behaviors in the rats that consumed the WD when compared with control animals 1 week after undergoing traumatic stress (p < 0.05). Magnetic resonance imaging showed significant hippocampal atrophy (20% reduction) and lateral ventricular enlargement (50% increase) in the animals fed the WD when compared with controls. These volumetric abnormalities were associated with behavioral indices of anxiety, increased leptin and FK506-binding protein 51 (FKBP51) levels, and reduced hippocampal blood vessel density. We found asymmetric structural vulnerabilities to the WD, particularly the ventral and left hippocampus and lateral ventricle. This study highlights how WD consumption during adolescence impacts key substrates implicated in post-traumatic stress disorder. Understanding how consumption of a WD affects the developmental trajectories of the stress neurocircuitry is critical, as stress susceptibility imposes a marked vulnerability to neuropsychiatric disorders.

Overexpressing Corticotropin-Releasing Factor in the Primate Amygdala Increases Anxious Temperament and Alters Its Neural Circuit

BACKGROUND

Nonhuman primate models are critical for understanding mechanisms underlying human psychopathology. We established a nonhuman primate model of anxious temperament (AT) for studying the early-life risk to develop anxiety and depression. Studies have identified the central nucleus of the amygdala (Ce) as an essential component of AT's neural substrates. Corticotropin-releasing factor (CRF) is expressed in the Ce, has a role in stress, and is linked to psychopathology. Here, in young rhesus monkeys, we combined viral vector technology with assessments of anxiety and multimodal neuroimaging to understand the consequences of chronically increased CRF in the Ce region.

METHODS

Using real-time intraoperative magnetic resonance imaging-guided convection-enhanced delivery, five monkeys received bilateral dorsal amygdala Ce-region infusions of adeno-associated virus serotype 2 containing the CRF construct. Their cagemates served as unoperated control subjects. AT, regional brain metabolism, resting functional magnetic resonance imaging, and diffusion tensor imaging were assessed before and 2 months after viral infusions.

RESULTS

Dorsal amygdala CRF overexpression significantly increased AT and metabolism within the dorsal amygdala. Additionally, we observed changes in metabolism in other AT-related regions, as well as in measures of functional and structural connectivity.

CONCLUSIONS

This study provides a translational roadmap that is important for understanding human psychopathology by combining molecular manipulations used in rodents with behavioral phenotyping and multimodal neuroimaging measures used in humans. The results indicate that chronic CRF overexpression in primates not only increases AT but also affects metabolism and connectivity within components of AT's neural circuitry.

Corticotropin-Releasing Factor and Toll-Like Receptor Gene Expression Is Associated with Low-Grade Inflammation in Irritable Bowel Syndrome Patients with Depression

The mechanism of low-grade inflammation in irritable bowel syndrome (IBS) is unclear; our research concentrates on the involvement of the corticotropin-releasing factor (CRF) and Toll-like receptor (TLR) gene expression in the process of low-grade inflammation in IBS patients with depression. This study suggests more IBS patients are presenting with the states of depression and anxiety. IBS patients with depression have shown a lower grade inflammatory response and an imbalance of the inflammatory response. CRF1, CRF2, TLR2, and TLR4 in IBS patients with depression are significantly higher than those without depression and controls. Thus, activation of the CRF-TLR associated pathways produces an inflammatory reaction, which can concurrently affect the digestive tract and the CNS and induce the corresponding digestive and psychiatric symptoms.

Review of Cohort Studies for Mood Disorders

This paper aimed to review currently available cohort studies of subjects with mood disorders such as major depressive disorder (MDD) and bipolar disorder (BD). Using the PubMed and KoreaMed databases, we reviewed eight major cohort studies. Most studies recruited participants with MDD and BD separately, so direct comparison of factors associated with diagnostic changes was difficult. Regular and frequent follow-up evaluations utilizing objective mood ratings and standardized evaluation methods in a naturalistic fashion are necessary to determine detailed clinical courses of mood disorders. Further, biological samples should also be collected to incorporate clinical findings in the development of new diagnostic and therapeutic approaches. An innovative cohort study that can serve as a platform for translational research for treatment and prevention of mood disorders is critical in determining clinical, psychosocial, neurobiological and genetic factors associated with long-term courses and consequences of mood disorders in Korean patients.

Circulating cytotoxic T cells and natural killer cells as potential predictors for antidepressant response in melancholic depression. Restoration of T regulatory cell populations after antidepressant therapy

RATIONALE

There is a substantial unmet need for biomarkers to predict treatment response in major depressive disorder (MDD). Evidence has converged on activation of the inflammatory response system as a fundamental mechanism underlying MDD.

OBJECTIVES

By investigating circulating leukocyte subsets quantified by fluorescence-activated cell sorting (FACS) analysis before treatment, we aim to predict antidepressant response.

METHODS

Forty medication-free inpatients with melancholic, non-psychotic depression before treatment with either venlafaxine or imipramine and 40 age- and gender-matched healthy controls were included. Leukocyte subsets were quantified by FACS analysis using frozen peripheral blood mononuclear cells (PBMC) collected prior to and after 7 weeks of treatment with either venlafaxine (375 mg/day) or imipramine (blood level 200-300 ng/ml). Response was defined as at least 50 % reduction of the baseline Hamilton Rating Scale for Depression (HAM-D) score.

RESULTS

Prior to treatment, MDD patients showed reduced percentages of CD4(+)CD25(high)Foxp3(+) T regulatory (Treg) cells when compared with controls (1.5 ± 0.6 vs. 1.8 ± 0.6, p = .037). After treatment, robust rises in Treg cells were observed in patients (1.8 ± 0.7, p < .001), yet Treg cells were not predictors of the clinical outcome of treatment. Antidepressant non-responders showed increased CD8(+) cytotoxic T cell percentages (24.0 ± 8.6 vs. 15.9 ± 5.9, p = .004) and decreased natural killer (NK) cell percentages (14.0 ± 6.9 vs. 21.4 ± 11.9, p = .020) compared with responders before treatment. Both lymphocyte levels were not significantly modulated by treatment.

CONCLUSION

In melancholic MDD, FACS analysis of circulating leukocyte subpopulations might help to discriminate between patients with high or low responsiveness to antidepressant treatment.

Associations between Single-Nucleotide Polymorphisms in Corticotropin-Releasing Hormone-Related Genes and Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common functional disorder with distinct features of stress-related pathophysiology. A key mediator of the stress response is corticotropin-releasing hormone (CRH). Although some candidate genes have been identified in stress-related disorders, few studies have examined CRH-related gene polymorphisms. Therefore, we tested our hypothesis that single-nucleotide polymorphisms (SNPs) in CRH-related genes influence the features of IBS.

METHODS

In total, 253 individuals (123 men and 130 women) participated in this study. They comprised 111 IBS individuals and 142 healthy controls. The SNP genotypes in CRH (rs28364015 and rs6472258) and CRH-binding protein (CRH-BP) (rs10474485) were determined by direct sequencing and real-time polymerase chain reaction. The emotional states of the subjects were evaluated using the State-Trait Anxiety Inventory, Perceived Stress Scale, and the Self-rating Depression Scale.

RESULTS

Direct sequencing of the rs28364015 SNP of CRH revealed no genetic variation among the study subjects. There was no difference in the genotype distributions and allele frequencies of rs6472258 and rs10474485 between IBS individuals and controls. However, IBS subjects with diarrhea symptoms without the rs10474485 A allele showed a significantly higher emotional state score than carriers.

CONCLUSIONS

These results suggest that the CRH and CRH-BP genes have no direct effect on IBS status. However, the CRH-BP SNP rs10474485 has some effect on IBS-related emotional abnormalities and resistance to psychosocial stress.

Personalized Medicine and Mood Disorders

Some of the latest advances in personalized psychiatry with future research directions are discussed in this article. Many factors contribute to the phenotypic psychiatric profile in individual patients. These overlapping factors include but are not limited to genetics, epigenetics, central nervous system circuit alterations, family history, past personal history, environmental influences including early life stress, and more recent life stressors. The authors discuss the role of pharmacogenomics, particularly in the cytochrome P450 enzyme system in relation to treatment response. Despite some promising advances in personalized medicine in psychiatry, it is still in its early phases of development.

Association analysis for corticotropin releasing hormone polymorphisms with the risk of major depressive disorder and the response to antidepressants

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis is one of the most consistent neuroendocrine abnormalities observed in patients with major depressive disorder (MDD). The peptide corticotropin-releasing hormone (CRH) is a key mediator for HPA axis function during stress. This study evaluated the associations of CRH polymorphisms with susceptibility to MDD and response to antidepressant treatment, and the gene-environment interaction with stressful life events (SLEs). After screening 31 polymorphisms in the gene encoding CRH, we evaluated the association of polymorphisms with MDD susceptibility in 149 patients with MDD and 193 control subjects; in patients, we also evaluated the response to treatment with antidepressants. Although genotypes and haplotypes were not significantly associated with the risk of MDD, non-remitters were more likely to carry haplotype 1 (ht1) than were remitters (P = 0.019-0.038), when only patients without SLE were included; however, the association was not significant after correction for multiple comparisons. Additionally, after 4 and 8 weeks of treatment in patients who experienced no SLEs, significantly higher 21-item Hamilton Depression Rating scores were found in MDD subjects who were CRH ht1 homozygotes compared to patients carrying one or no ht1 alleles (P = 0.007 and 0.027 at 4 and 8 weeks, respectively). Although these preliminary observations require further confirmation in future studies, these results on the interaction between CRH haplotypes and SLEs, suggest that CRH ht1 which is moderated by SLEs, may be associated with antidepressant treatment outcomes in patients with MDD.

Light treatment for seasonal Winter depression in African-American vs Caucasian outpatients

AIM: To compare adherence, response, and remission with light treatment in African-American and Caucasian patients with Seasonal Affective Disorder.

METHODS: Seventy-eight study participants, age range 18-64 (51 African-Americans and 27 Caucasians) recruited from the Greater Baltimore Metropolitan area, with diagnoses of recurrent mood disorder with seasonal pattern, and confirmed by a Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders-IV, were enrolled in an open label study of daily bright light treatment. The trial lasted 6 wk with flexible dosing of light starting with 10000 lux bright light for 60 min daily in the morning. At the end of six weeks there were 65 completers. Three patients had Bipolar II disorder and the remainder had Major depressive disorder. Outcome measures were remission (score ≤ 8) and response (50% reduction) in symptoms on the Structured Interview Guide for the Hamilton Rating Scale for Depression (SIGH-SAD) as well as symptomatic improvement on SIGH-SAD and Beck Depression Inventory-II. Adherence was measured using participant daily log. Participant groups were compared using t-tests, chi square, linear and logistic regressions.

RESULTS: The study did not find any significant group difference between African-Americans and their Caucasian counterparts in adherence with light treatment as well as in symptomatic improvement. While symptomatic improvement and rate of treatment response were not different between the two groups, African-Americans, after adjustment for age, gender and adherence, achieved a significantly lower remission rate (African-Americans 46.3%; Caucasians 75%; P = 0.02).

CONCLUSION: This is the first study of light treatment in African-Americans, continuing our previous work reporting a similar frequency but a lower awareness of SAD and its treatment in African-Americans. Similar rates of adherence, symptomatic improvement and treatment response suggest that light treatment is a feasible, acceptable, and beneficial treatment for SAD in African-American patients. These results should lead to intensifying education initiatives to increase awareness of SAD and its treatment in African-American communities to increased SAD treatment engagement. In African-American vs Caucasian SAD patients a remission gap was identified, as reported before with antidepressant medications for non-seasonal depression, demanding sustained efforts to investigate and then address its causes.

The association of proopiomelanocortin polymorphisms with the risk of major depressive disorder and the response to antidepressants via interactions with stressful life events

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis is among the most consistent neuroendocrine abnormalities in major depressive disorder (MDD). The peptide adrenocorticotropin hormone (ACTH) mediates HPA axis function during stress and is encoded by the proopiomelanocortin (POMC) gene polycistronically. After screening 39 POMC polymorphisms, we evaluated the association of polymorphisms with susceptibility to MDD in 145 MDD patients and 193 normal subjects; in patients, we also evaluated the response to treatment with antidepressants. Additionally, we investigated the role of gene-environment interaction between POMC haplotypes and stressful life events (SLE) in the treatment response. Although genotypes and haplotypes were not significantly associated with the risk of MDD, non-remitters were more likely to carry haplotype 1 (ht1) and to have no ht2 than were remitters (corrected P = 0.010-0.035). Although observations were limited in patients without SLE, a significant haplotype-SLE interaction was observed (P = 0.020). Additionally, at 1, 2, and 8 weeks of treatment, the 21-item Hamilton Depression Rating scores of MDD subjects with POMC ht2 were significantly (P = 0.003-0.044) lower than those of patients with ht1 in subjects those did not experience SLE. MDD subjects possessing POMC ht2 achieved remission significantly (P = 0.013; survival analysis) faster than patients with ht1. This study suggests that POMC haplotypes, via an interaction with SLE, are associated with antidepressant treatment outcomes in MDD patients. Regarding SLE, haplotypes of the POMC gene could be useful markers for predicting the response to antidepressant treatment in MDD patients.

Relationship of cortisol levels and genetic polymorphisms to antidepressant response to placebo and fluoxetine in patients with major depressive disorder: a prospective study

BACKGROUND

Increased cortisol levels and genetic polymorphisms have been related to both major depressive disorder and antidepressant treatment outcome. The aim of this study is to evaluate the relationship between circadian salivary cortisol levels, cortisol suppression by dexamethasone and genetic polymorphisms in some HPA axis-related genes to the response to placebo and fluoxetine in depressed patients.

METHODS

The diagnosis and severity of depression were performed using the Mini International Neuropsychiatric Interview (M.I.N.I.) and Hamilton depression scale (HAM-D17), respectively. Euthyroid patients were treated with placebo (one week) followed by fluoxetine (20 mg) (two months). Severity of depression was re-evaluated after placebo, three weeks and two months of fluoxetine treatments. Placebo response was defined as HAM-D17 score reductions of at least 25% and to < 15. Early response and response were reductions of at least 50% after three weeks and two months, and remission with ≤ 7 after two months. Plasma TSH, free-T4, circadian salivary cortisol levels and cortisol suppression by dexamethasone were evaluated. Seven genetic polymorphisms located in the Corticotrophin-releasing-hormone-receptor-1 (rs242939, rs242941, rs1876828), Corticotrophin-releasing-hormone-receptor-2 (rs2270007), Glucocorticoid-receptor (rs41423247), FK506-binding-protein-5 (rs1360780), and Arginine-vasopressin (rs3729965) genes were determined. Association analyses between response to placebo/fluoxetine and polymorphism were performed by chi-square or Fisher exact test. Cortisol levels were compared by t-test, ANOVA and the general linear model for repeated measures.

RESULTS

208 depressed patients were recruited, 187 of whom were euthyroid. Placebo responders, fluoxetine responders and remitters exhibited significantly lower circadian cortisol levels than those who did not respond (p-values of 0.014, 0.008 and 0.021 respectively). Patients who abandoned treatment before the third week also exhibited a trend to low cortisol levels (p = 0.057). The polymorphisms rs242939 (CRHR1) and rs2270007 (CRHR2) were not in Hardy-Weinberg equilibrium. Only the rs242939 polymorphism (CRHR1) exhibited association with early response (three weeks) to fluoxetine (p-value = 0.043). No other association between outcomes and polymorphisms was observed.

CONCLUSIONS

These results support the clinical relevance of low salivary cortisol levels as a predictor of antidepressant response, either to placebo or to fluoxetine. Only one polymorphism in the CRHR1 gene was associated with the early response. Other factors may be involved in antidepressant response, although further studies are needed to identify them.

Childhood maltreatment and the course of bipolar disorders among adults: epidemiologic evidence of dose-response effects

BACKGROUND

Childhood maltreatment (CM) is highly prevalent among individuals with bipolar disorders (BP); however few studies have examined its potential role in the course and outcome of individuals with BP. We aim to examine the dose response relationship between the number of types of CM and the course of individuals with BP.

METHODS

As part of the National Epidemiologic Survey on Alcohol and Related Conditions, 1600 adults who met lifetime DSM-IV criteria for BP-I (n=1172) and BP-II (n=428) were included. Individuals were evaluated using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-DMS-IV Version and data was analyzed lifetime and from Waves 1 and 2, approximately 3 years apart.

RESULTS

Around half of individuals with BP had a history of at least one type of CM. Overall, there was a clear dose-response relationship between number of CM and severity of BP across several domains, including clinical characteristics, probability of treatment, lifetime prevalence of psychiatric comorbidity, incidence of anxiety disorders, substance use disorder, and nicotine dependence, and level of psychosocial functioning.

LIMITATIONS

The interviews were conducted by lay professional interviewers rather than clinicians, use of retrospective report to determine CM in individuals with BP, and not all respondents from Wave 1 were able to be interviewed in Wave 2.

CONCLUSIONS

The number of types of CM confers developmental differences in the course of BP with a worse course and outcome of BP. Early identification and treatment of CM are warranted to improve the course and outcome of individuals with BP.

Understanding the pharmacogenetics of selective serotonin reuptake inhibitors

INTRODUCTION

The genetic background of antidepressant response represents a unique opportunity to identify biological markers of treatment outcome. Encouraging results alternating with inconsistent findings made antidepressant pharmacogenetics a stimulating but often discouraging field that requires careful discussion about cumulative evidence and methodological issues.

AREAS COVERED

The present review discusses both known and less replicated genes that have been implicated in selective serotonin reuptake inhibitors (SSRIs) efficacy and side effects. Candidate genes studies and genome-wide association studies (GWAS) were collected through MEDLINE database search (articles published till January 2014). Further, GWAS signals localized in promising genetic regions according to candidate gene studies are reported in order to assess the general comparability of results obtained through these two types of pharmacogenetic studies. Finally, a pathway enrichment approach is applied to the top genes (those harboring SNPs with p < 0.0001) outlined by previous GWAS in order to identify possible molecular mechanisms involved in SSRI effect.

EXPERT OPINION

In order to improve the understanding of SSRI pharmacogenetics, the present review discusses the proposal of moving from the analysis of individual polymorphisms to genes and molecular pathways, and from the separation across different methodological approaches to their combination. Efforts in this direction are justified by the recent evidence of a favorable cost-utility of gene-guided antidepressant treatment.

Pharmacologic treatment of dimensional anxious depression: a review

OBJECTIVE

To review the pharmacologic treatment of dimensionally defined anxious depression.

DATA SOURCES

English-language, adult human research articles published between 1949 and February 2013 were identified via PUBMED and EMBASE. The search term was treatment of anxious depression.

STUDY SELECTION

We identified and reviewed 304 original articles. Of these, 31 studies of patients with anxious depression, who were treated with an antidepressant or antipsychotic, are included in this review.

DATA EXTRACTION

All studies explicitly used a dimensional definition of anxious depression. All patients were treated with either antidepressants or antipsychotic medications.

RESULTS

Of the 31 relevant psychopharmacologic studies identified, 7 examined patients receiving only 1 medication, 2 studied cotherapeutic strategies, 1 examined antipsychotic augmentation, and 21 compared multiple medications. Eleven were pooled analyses from several studies. All studies were of adults (18-92 years old). The Hamilton Depression Rating Scale Anxiety/Somatization Factor Score was used to define anxious depression in 71% of the studies, and 77.4% were post hoc analyses of previous datasets. Seventeen studies found selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and/or tricyclic antidepressants (TCAs) to be useful for successfully treating anxious depression. However, patients with anxious depression were less likely to experience sustained response or remission. Furthermore, baseline anxious depression puts patients at greater risk for side effect burden.

CONCLUSIONS

Despite achieving response with SSRIs, SNRIs, and TCAs, patients with dimensionally defined anxious depression do not maintain response or remission and often report a larger burden of side effects compared to nonanxious depressive patients, suggesting that it is a harder-to-treat subtype of major depressive disorder.

HPA axis genetic variation, cortisol and psychosis in major depression

Genetic variation underlying hypothalamic pituitary adrenal (HPA) axis overactivity in healthy controls (HCs) and patients with severe forms of major depression has not been well explored, but could explain risk for cortisol dysregulation. In total, 95 participants were studied: 40 patients with psychotic major depression (PMD); 26 patients with non-psychotic major depression (NPMD); and 29 HCs. Collection of genetic material was added one third of the way into a larger study on cortisol, cognition and psychosis in major depression. Subjects were assessed using the Brief Psychiatric Rating Scale, the Hamilton Depression Rating Scale and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders. Blood was collected hourly for determination of cortisol from 1800 to 0900 h and for the assessment of alleles for six genes involved in HPA axis regulation. Two of the six genes contributed significantly to cortisol levels, psychosis measures or depression severity. After accounting for age, depression and psychosis, and medication status, only allelic variation for the glucocorticoid receptor (GR) gene accounted for a significant variance for mean cortisol levels from 1800 to 0100 h (r(2)=0.288) and from 0100 to 0900 h (r(2)=0.171). In addition, GR and corticotropin-releasing hormone receptor 1 (CRHR1) genotypes contributed significantly to psychosis measures and CRHR1 contributed significantly to depression severity rating.

From pharmacogenetics to pharmacogenomics: the way toward the personalization of antidepressant treatment

OBJECTIVE

Major depressive disorder is the most common psychiatric disorder, worldwide, yet response and remission rates are still unsatisfactory. The identification of genetic predictors of antidepressant (AD) response could provide a promising opportunity to improve current AD efficacy through the personalization of treatment. The major steps and findings along this path are reviewed together with their clinical implications and limitations.

METHOD

We systematically reviewed the literature through MEDLINE and Embase database searches, using any word combination of "antidepressant," "gene," "polymorphism," "pharmacogenetics," "genome-wide association study," "GWAS," "response," and "adverse drug reactions." Experimental works and reviews published until March 2012 were collected and compared.

RESULTS

Numerous genes pertaining to several functional systems were associated with AD response. The more robust findings were found for the following genes: solute carrier family 6 (neurotransmitter transporter), member 4; serotonin receptor 1A and 2A; brain-derived neurotrophic factor; and catechol-O-methyltransferase. Genome-wide association studies (GWASs) provided many top markers, even if none of them reached genome-wide significance.

CONCLUSIONS

AD pharmacogenetics have not produced any knowledge applicable to routine clinical practice yet, as results were mainly inconsistent across studies. Despite this, the rising awareness about methodological deficits of past studies could allow for the identication of more suitable strategies, such as the integration of the GWAS approach with the candidate gene approach, and innovative methodologies, such as pathway analysis and study of depressive endophenotypes.

A pilot investigation of the association of genetic polymorphisms regulating corticotrophin-releasing hormone with posttraumatic stress and depressive symptoms in medical-surgical intensive care unit survivors

PURPOSE

To determine if single nucleotide polymorphisms of the corticotrophin-releasing hormone binding protein (CRHBP, rs10055255) and CRH receptor type 1 (CRHR1, rs1876831) were associated with posttraumatic stress disorder (PTSD) and depressive symptoms following medical-surgical intensive care unit (ICU) hospitalization.

MATERIALS AND METHODS

We extracted DNA for genotyping from saliva samples of 93 ICU patients enrolled in a prospective cohort investigation. Follow-up interviews conducted 3 and 12-months post-ICU included assessment of PTSD symptoms with the PTSD Checklist-Civilian Version and depressive symptoms with the Patient Health Questionnaire-9.

RESULTS

Homozygosity for the CRHBP rs10055255 T allele was associated with significantly fewer post-ICU PTSD (β = -10.8, 95% confidence interval [95% CI], -17.7 to -3.9; P = .002) and depressive symptoms (β = -3.7, 95% CI, -6.7 to -0.7; P = .02). Carrying a CRHR1 rs1876831 C allele was associated with significantly more post-ICU depressive symptoms compared to T/T homozygotes (C/T heterozygtes: β = 6.9, 95% CI, 1.2-12.6; P = .02; C/C homozygotes: β = 5.8; 95% CI: 0.2-11.3; P = .04). These associations remained significant after adjustment for age, race, illness severity, and in-ICU steroid exposure.

CONCLUSIONS

Despite a small sample size, our findings suggest a potential role for genetic variants of CRHBP and CRHR1 in the development of post-ICU psychiatric morbidity.

Pharmacogenetics of antidepressant drugs: an update after almost 20 years of research

Major depressive disorder (MDD) is an emergent cause of personal and socio-economic burden, both for the high prevalence of the disorder and the unsatisfying response rate of the available antidepressant treatments. No reliable predictor of treatment efficacy and tolerance in the single patient is available, thus drug choice is based on a trial and error principle with poor clinical efficiency. Among modulators of treatment outcome, genetic polymorphisms are thought to explain a significant share of the inter-individual variability. The present review collected the main pharmacogenetic findings primarily about antidepressant response and secondly about antidepressant induced side effects, and discussed the main strengths and limits of both candidate and genome-wide association studies and the most promising methodological opportunities and challenges of the field. Despite clinical applications of antidepressant pharmacogenetics are not available yet, previous findings suggest that genotyping may be applied in the clinical practice. In order to reach this objective, further rigorous pharmacogenetic studies (adequate sample size, study of better defined clinical subtypes of MDD, adequate covering of the genetic variability), their combination with the results obtained through complementary methodologies (e.g., pathway analysis, epigenetics, transcriptomics, and proteomics), and finally cost-effectiveness trials are required.

Family-based study of AVPR1B association and interaction with stressful life events on depression and anxiety in suicide attempts

The cortisol response to psychosocial stress may become dysregulated in stress-related disorders. It is potentiated by pituitary secretion of adrenocorticotropic hormone (ACTH), which is, in part, regulated by arginine vasopressin receptor-1B (AVPR1B). AVPR1B variants were previously reported to associate with mood and anxiety disorders. This study aims, for the first time, to investigate association of AVPR1B genetic variants with mood and anxiety outcomes in suicidal behavior.Using a family-based study design of 660 complete nuclear family trios with offspring who have made a suicide attempt (SA), we tested the direct association and linkage of AVPR1B single nucleotide polymorphisms (SNPs) with SA, as well as with depression and anxiety in SA. Main findings were the association and linkage of AVPR1B exon 1 SNP rs33990840 and a major 6-SNP haplotype representative of all common AVPR1B-SNPs, on the outcome of high Beck Depression Inventory scores in SA. By contrast, genetic associations with lifetime diagnoses of depression and anxiety in SA or gene-environment interactions between AVPR1B variants and stressful life events (SLEs) were not significant. An exploratory screen of interactions between AVPR1B and CRHR1 (corticotropin-releasing hormone receptor-1), the principal pituitary regulator of ACTH secretion, showed no support for gene-gene interactions on the studied outcomes. The results suggest that AVPR1B genetic variation, eg, non-synonymous SNP rs33990840 mediating putative consequences on ligand binding, has a role in SA etiology characterized by elevated depression symptoms, without involving AVPR1B-moderation of SLEs.

Anxiety and 10-year risk of incident and recurrent depressive symptomatology in older adults

BACKGROUND

Anxiety has been shown to often precede depression in children and young adults. Only a small number of investigations have examined this form of comorbidity in older adults and the temporal relationship of these syndromes remains unclear. The objective was to verify whether trait anxiety predicts incident/recurrent depressive symptomatology in older adults independently of variables susceptible to explain this relationship in this population, such as cognitive complaints, subjective health, and baseline depressive symptoms.

METHODS

A random sample of 4,649 individuals aged 65 years or older from the Three-City Study, a prospective longitudinal study with a 10-year follow-up, was used. Incident and recurrent depressive symptomatology were determined by Center for Epidemiological Studies Depression Scale cutoff scores. Anxiety was measured using the trait scale of the State-Trait Anxiety Inventory. Cox proportional hazards models were used to determine the independent risk of depressive symptomatology for baseline anxiety, cognitive complaints, subjective health, and depressive symptoms, adjusting for sociodemographic, mental health, and physical health covariates.

RESULTS

Incident depressive symptomatology was independently predicted by baseline anxiety, depressive symptoms, cognitive complaints, and subjective health. Recurrent depressive symptomatology was independently predicted by baseline anxiety and depressive symptoms, but not by cognitive complaints and subjective health. Anxiety was associated with a higher risk of incident depressive symptomatology only in participants without a history of a major depressive episode, and with a higher risk of recurrent depressive symptomatology in men than in women.

CONCLUSIONS

Trait anxiety constitutes an important independent risk factor for subsequent depressive symptomatology in older adults.

Personalized medicine in psychiatry: problems and promises

The central theme of personalized medicine is the premise that an individual's unique physiologic characteristics play a significant role in both disease vulnerability and in response to specific therapies. The major goals of personalized medicine are therefore to predict an individual's susceptibility to developing an illness, achieve accurate diagnosis, and optimize the most efficient and favorable response to treatment. The goal of achieving personalized medicine in psychiatry is a laudable one, because its attainment should be associated with a marked reduction in morbidity and mortality. In this review, we summarize an illustrative selection of studies that are laying the foundation towards personalizing medicine in major depressive disorder, bipolar disorder, and schizophrenia. In addition, we present emerging applications that are likely to advance personalized medicine in psychiatry, with an emphasis on novel biomarkers and neuroimaging.

Analysis of 34 candidate genes in bupropion and placebo remission

There is considerable variability in the rate of response and remission following treatment with antidepressant drugs or placebo in depression patients. No pharmacogenetic studies of bupropion response have been done. We investigated 532 tagging single nucleotide polymorphisms (SNPs) in 34 candidate genes for association with remission and response to either bupropion (n=319) or placebo (n=257) in patients with major depressive disorder. Analyses were performed using conditional logistic regression. Significant association (gene-wide correction) was observed for remission following treatment with bupropion for a SNP within the serotonin receptor 2A gene (HTR2A rs2770296, p(corrected)=0.02). Response to bupropion treatment was significantly associated with a SNP in the dopamine transporter gene (rs6347, p(corrected)=0.013). Among the patients who received placebo, marginal association for remission was observed between a SNP in HTR2A (rs2296972, p(corrected)=0.055) as well as in the serotonin transporter gene (5-HTT or SLC6A4 rs4251417, p(corrected)=0.050). Placebo response was associated with SNPs in the glucocorticoid receptor gene (NR3C1; rs1048261, p(corrected)=0.040) and monoamine oxidase A gene (MAOA; rs6609257, p corrected=0.046). Although the above observations were significant after gene-wide corrections, none of these would be significant after a more conservative study-wide correction for multiple tests. These results suggest a possible role for HTR2A in remission to bupropion treatment. In accordance with bupropion pharmacology, dopamine transporter may play a role in response. The MAOA gene may be involved in placebo response.

Neurobiology of anxious depression: a review

Anxious depression is a common, distinct clinical subtype of major depressive disorder (MDD). This review summarizes current neurobiological knowledge regarding anxious depression. Peer-reviewed articles, published January 1970 through September 2012, were identified via PUBMED, EMBASE, and Cochrane Library, using the following key words: anxious depression electroencephalography (EEG), anxious depression functional magnetic resonance imaging (fMRI), anxious depression genetics, anxious depression neurobiology, and anxious melancholia neurobiology. Despite a general dearth of neurobiological research, the results suggest that anxious depression-when defined either syndromally or dimensionally-has distinct neurobiological findings that separate it from nonanxious depression. Structural neuroimaging, EEG, genetics, and neuropsychiatric studies revealed differences in subjects with anxious depression compared to other groups. Endocrine differences between individuals with anxious depression and those with nonanxious depression have also been noted, as evidenced by abnormal responses elicited by exogenous stimulation of the system. Despite these findings, heterogeneity in the definition of anxious depression complicates the results. Because exploring the neurobiology of this depressive subtype is important for improving diagnosis, prognosis, and treatment, enrichment strategies to decrease heterogeneity within the field should be employed for future research.