The serotonin transporter promoter variant (5-HTTLPR), stress, and depression meta-analysis revisited: evidence of genetic moderation

5-HTTLPR and use of antidepressants after colorectal cancer including a meta-analysis of 5-HTTLPR and depression after cancer

The serotonin-transporter-linked polymorphic region (5-HTTLPR) is one of the most extensively investigated candidates to be involved in gene-environment interaction associated with depression. Nevertheless, the interaction remains controversial. In an original study, we tested the hypothesis that risk for use of antidepressants following a diagnosis of colorectal cancer is associated with bi- and triallelic genotypes of 5-HTTLPR. In addition, in an inclusive meta-analysis, we tested the hypothesis that depression following a diagnosis of cancer is associated with biallelic 5-HTTLPR genotype. We created an exposed-only cohort of 849 colorectal cancer patients from the Danish Diet, Cancer and Health cohort study. The hypothesized association was investigated with Cox regression models and competing risk analyses. Five studies comprising a total of 1484 cancer patients were included in the meta-analysis. Nationwide registries provided information on dates of diagnosis of colorectal cancer and use of antidepressants. Unadjusted odds ratios of depression according to the biallelic 5-HTTLPR genotype were included in the meta-analysis. 5-HTTLPR genotypes were not associated with use of antidepressants after colorectal cancer. Estimated hazard ratios ranged 0.92-1.08, and we observed no statistically significant associations across biallelic and triallelic genotypes in crude as well as adjusted models. The meta-analysis showed no statistically significant associations of 5-HTTLPR biallelic genotype with depression after cancer. Our findings in an original study and a meta-analysis do not support the hypothesis of an association between the 5-HTTLPR genotype and depression after cancer.

Examining gene-environment interactions in comorbid depressive and disruptive behavior disorders using a Bayesian approach

OBJECTIVE

The objective of this study was to apply a Bayesian statistical analytic approach that minimizes multiple testing problems to explore the combined effects of chronic low familial support and variants in 12 candidate genes on risk for a common and debilitating childhood mental health condition.

METHOD

Bayesian mixture modeling was used to examine gene by environment interactions among genetic variants and environmental factors (family support) associated in previous studies with the occurrence of comorbid depression and disruptive behavior disorders youth, using a sample of 255 children.

RESULTS

One main effect, variants in the oxytocin receptor (OXTR, rs53576) was associated with increased risk for comorbid disorders. Two significant gene × environment and one signification gene × gene interactions emerged. Variants in the nicotinic acetylcholine receptor α5 subunit (CHRNA5, rs16969968) and in the glucocorticoid receptor chaperone protein FK506 binding protein 5 (FKBP5, rs4713902) interacted with chronic low family support in association with child mental health status. One gene × gene interaction, 5-HTTLPR variant of the serotonin transporter (SERT/SLC6A4) in combination with μ opioid receptor (OPRM1, rs1799971) was associated with comorbid depression and conduct problems.

CONCLUSIONS

Results indicate that Bayesian modeling is a feasible strategy for conducting behavioral genetics research. This approach, combined with an optimized genetic selection strategy (Vrieze et al., 2012), revealed genetic variants involved in stress regulation (FKBP5, SERT × OPMR), social bonding (OXTR), and nicotine responsivity (CHRNA5) in predicting comorbid status.

Polymorphism in the promoter of the gene for the serotonin transporter affects the age of onset of major depressive disorder in the Japanese population

OBJECTIVE

Recent research has suggested that a functional polymorphism in the promoter region of the serotonin transporter gene (serotonin transporter-linked polymorphic region, 5HTTLPR) may be implicated in gene-environment interactions leading to major depressive disorder (MDD).

METHODS

Our study examined the association between 5HTTLPR and clinical variables of MDD in the Japanese population. We genotyped 5HTTLPR in 216 patients with MDD and 213 age- and sex-matched controls.

RESULTS

The genotype distributions and allele frequencies were similar in the patients and controls. When the relationships between the polymorphism and several clinical variables (i.e., age of onset, number of episodes, presence of psychotic features, suicidal behavior, and family history) were examined, the dose of the long (l) allele had significant effects on the age of onset.

CONCLUSION

These results suggest that 5HTTLPR may not be entirely related to the development of MDD but may be related to the age of onset of MDD, which may be due to gene-environment interactions in the Japanese population.

LIMITATIONS

Because of the low frequencies of psychotic features and suicidal behavior, our results must be treated with caution until they are replicated in larger numbers of Japanese samples. MDD patients did not undergo a structured interview. Clinical information from the medical records may have not been complete.

Is trait resilience characterized by specific patterns of attentional bias to emotional stimuli and attentional control?

BACKGROUND AND OBJECTIVES

Attentional processes have been suggested to play a crucial role in resilience defined as positive adaptation facing adversity. However, research is lacking on associations between attentional biases to positive and threat-related stimuli, attentional control and trait resilience.

METHODS

Data stem from the follow-up assessment of a longitudinal study investigating mental health and related factors among German soldiers. Trait resilience was assessed with the Connor-Davidson Resilience Scale and attentional control with the Attentional Control Scale. A subset of n = 198 soldiers also completed a dot probe task with happy, neutral and threatening faces.

RESULTS

Attentional control was positively related to trait resilience. Results revealed no associations between both attentional biases and trait resilience. However, there was a negative association between attentional bias to threat and trait resilience when attentional control was low and a positive association between attentional bias to threat and trait resilience when attentional control was high. No such associations were found for attentional bias to positive stimuli.

LIMITATIONS

Generalizability to other populations may be limited since we exclusively focused on male soldiers. Also, the cross-sectional design does not allow for causal conclusions.

CONCLUSIONS

Findings suggest that attentional processing may promote trait resilience. Future research on preventive interventions should consider these findings.

Treating Anxiety Disorders in Older Adults: Current Treatments and Future Directions

Anxiety disorders are highly prevalent among the elderly and are associated with increased disability, poor quality of life, and cognitive impairment. Despite this high prevalence and associated morbidities, anxiety disorders in late life are underreported and understudied. In this article, we discuss the epidemiology, disease presentation, and current treatment of anxiety disorders in older adults. We also discuss limitations in the current understanding of such disorders in this population, as well as future research directions that may reveal the mechanisms and rationale for treatment regimens for anxiety disorders in late life. We present material on the application of the Research Domain Criteria (RDoC) model to geriatric anxiety. Finally, we describe optimal management strategies of anxiety disorders.

The Power of Theory, Research Design, and Transdisciplinary Integration in Moving Psychopathology Forward

While the past few decades have seen much work in psychopathology research that has yielded provocative insights, relatively little progress has been made in understanding the etiology of mental disorders. We contend that this is due to an overreliance on statistics and technology with insufficient attention to adequacy of experimental design, a lack of integration of data across various domains of research, and testing of theoretical models using relatively weak study designs. We provide a conceptual discussion of these issues and follow with a concrete demonstration of our proposed solution. Using two different disorders - depression and substance use - as examples, we illustrate how we can evaluate competing theories regarding their etiology by integrating information from various domains including latent variable models, neurobiology, and quasi-experimental data such as twin and adoption studies, rather than relying on any single methodology alone. More broadly, we discuss the extent to which such integrative thinking allows for inferences about the etiology of mental disorders, rather than focusing on descriptive correlates alone. Greater scientific insight will require stringent tests of competing theories and a deeper conceptual understanding of the advantages and pitfalls of methodologies and criteria we use in our studies.

Epigenetic variation in the serotonin transporter gene predicts resting state functional connectivity strength within the salience-network

Genetic variation in the serotonin transporter gene (SLC6A4) has been associated with psychopathology and aberrant brain functioning in a plethora of clinical and imaging studies. In contrast, the neurobiological correlates of epigenetic signatures in SLC6A4, such as DNA methylation profiles, have only recently been explored in human brain imaging research. The present study is the first to apply a resting state functional magnetic resonance imaging approach to identify changes in brain networks related to SLC6A4 promoter methylation (N=74 healthy individuals). The amygdalae were defined as seed regions given that resting state functional connectivity in this brain area is under serotonergic control and relates to a broad range of psychiatric phenotypes. We further used bisulfite pyrosequencing to analyze quantitative methylation at 83 CpG sites within a promoter-associated CpG island of SLC6A4 from blood-derived DNA samples. The major finding of this study indicates a positive relation of SLC6A4 promoter methylation and amygdaloid resting state functional coupling with key nodes of the salience network (SN) including the anterior insulae and the dorsal anterior cingulate cortices. Increased intra-network connectivity in the SN is thought to facilitate the detection and subsequent processing of potentially negative stimuli and reflects a core feature of psychopathology. As such, epigenetic changes within the SLC6A4 gene predict connectivity patterns in clinically and behaviorally relevant brain networks which may in turn convey increased disease susceptibility.

Development and the epigenome: the 'synapse' of gene-environment interplay

This paper argues that there is a revolution afoot in the developmental science of gene-environment interplay. We summarize, for an audience of developmental researchers and clinicians, how epigenetic processes - chromatin structural modifications that regulate gene expression without changing DNA sequences - may offer a strong, parsimonious account for the convergence of genetic and contextual variation in the genesis of adaptive and maladaptive development. Epigenetic processes may play a plausible explanatory role in understanding: divergent trajectories and sexual dimorphisms in brain development; statistical interactions between genes and environments; the biological embedding of early psychosocial adversities; the linkages of such adversities to disorders of mental health; the striking individual variation in the strength of those linkages; the molecular origins of critical and sensitive periods; and the transgenerational inheritance of risk and protection. Taken together, these arguments converge in a claim that epigenetic processes constitute a promising and illuminating point of connection - a 'synapse' - between genes and environments.

Impact of Childhood Adversity and Vasopressin receptor 1a Variation on Social Interaction in Adulthood: A Cross-Sectional Study

Background

Arginine vasopressin (AVP) plays a role in social behavior, through receptor AVPR1A. The promoter polymorphism AVPR1A RS3 has been associated with human social behaviors, and with acute response to stress. Here, the relationships between AVPR1A RS3, early-life stressors, and social interaction in adulthood were explored.

Methods

Adult individuals from a Swedish population-based cohort (n = 1871) were assessed for self-reported availability of social integration and social attachment and for experience of childhood adversities. Their DNA samples were genotyped for the microsatellite AVPR1A RS3.

Results

Among males, particularly those homozygous for the long alleles of AVPR1A RS3 were vulnerable to childhood adversity for their social attachment in adulthood. A similar vulnerability to childhood adversity among long allele carriers was found on adulthood social integration, but here both males and females were influenced.

Limitation

Data were self-reported and childhood adversity data were retrospective.

Conclusions

Early-life stress influenced the relationship between AVPR1A genetic variants and social interaction. For social attachment, AVPR1A was of importance in males only. The findings add to previous reports on higher acute vulnerability to stress in persons with long AVPR1A RS3 alleles and increased AVP levels.

Sensitizing effect of early adversity on depressive reactions to later proximal stress: Moderation by polymorphisms in serotonin transporter and corticotropin releasing hormone receptor genes in a 20-year longitudinal study

Previous research supports gene-environment interactions for polymorphisms in the corticotropin hormone receptor 1 gene (CRHR1) and the serotonin transporter gene linked polymorphic region (5-HTTLPR) in predicting depression, but it has rarely considered genetic influences on stress sensitization processes, whereby early adversities (EA) increase depressive reactivity to proximal stressors later in life. The current study tested a gene-environment-environment interaction (G × E × E; specifically, gene-EA-proximal stress interaction) model of depression in a 20-year longitudinal study. Participants were assessed prospectively for EA up to age 5 and recent chronic stress and depressive symptoms at age 20 and genotyped for CRHR1 single nucleotide polymorphism rs110402 and 5-HTTLPR. EA predicted stronger associations between recent chronic stress and depression, and the effect was moderated by genes. CRHR1 A alleles and 5-HTTLPR short alleles were associated with greater stress sensitization (i.e., greater depressive reactivity to chronic stress for those also exposed to high levels of EA). The results are consistent with the notion that EA exposure results in neurobiological and cognitive-emotional consequences (e.g., altered hypothalamic-pituitary-adrenal axis functioning), leading to emotional distress in the face of recent stressors among those with certain genetic characteristics, although further research is needed to explore explanatory mechanisms.

Serotonin transporter availability may moderate the association between perceiving stress and depressive tendencies - A SPECT with 5-HTTLPR genotyping study

It was found that serotonin transporter (SERT) gene (5-HTTLPR) polymorphism may moderate the association between perceiving stress and depressive tendency. Although SERT availability in the central nervous system could be associated with 5-HTTLPR polymorphism, whether SERT availability moderates the association between stress and depressive tendency is unclear. This study aimed to investigate whether there is a SERT availability×environmental stress interaction effect, as well as a gene-by-environmental (G×E) interaction effect, using single-photon emission computed tomography (SPECT) with a serotonin transporter radiotracer, [(123)I]ADAM. 87 healthy volunteers were enrolled. The SERT availability was approximated using SPECT with [(123)I]ADAM. Stress and depressive tendencies were measured by the Recent Life Change Questionnaire (RLCQ) and the Taiwanese Depression Questionnaire (TDQ), respectively. A significant interaction of sex×RLCQ×thalamic SERT availability on the TDQ was found, and this effect was robust after controlling for the effect of the SS genotype. The interaction of RLCQ×thalamic SERT availability on the TDQ was significant among males. In particular, a significant association between RLCQ and TDQ (Spearman correlation, ρ=0.64, p<0.01) was found among male subjects with a lower level of thalamic SERT availability. SERT availability may play a role in depressive tendency when under perceived stress among healthy individuals, independent of G×E. This finding provides new evidence that confirms the role of the serotonergic system in the association between stress and depression. Males with lower levels of SERT availability may be more vulnerable to the effects of negative life events.

Association of Anxiety Symptoms in Offspring of Bipolar Parents with Serotonin Transporter-Linked Polymorphic Region (5-HTTLPR) Genotype

OBJECTIVE

Offspring of parents with bipolar disorder (BD) have been shown to be at high risk for BD. Anxiety symptoms, even at subclinical levels, have been associated with increased risk for BD in these youth. The s-allele of the serotonin transporter-linked polymorphic region (5-HTTLPR) has been implicated in the pathophysiology of both BD and anxiety disorders and has been associated with pharmacological treatment response and increased risk for antidepressant side effects. Therefore, we aimed to explore 1) whether anxiety symptoms in offspring of BD parents were associated with presence of the 5-HTTLPR s-allele and 2) whether anxiety symptoms in the offspring of BD parents according to the 5-HTTLPR genotypes are related to antianxiety medication status.

METHODS

A total of 64 offspring of BD parents (mean age: 13.7 years) and 51 healthy controls (HC) (mean age: 13.7 years) were compared genetically and on the Multidimensional Anxiety Scale for Children (MASC).

RESULTS

Offspring of BD parents showed higher levels of overall anxiety than did the HC group. Only antianxiety medication naïve offspring of BD parents were found to have an association between 5-HTTLPR genotypes and anxiety symptoms. The antianxiety medication naïve offspring of BD parents with the s-allele showed higher level of overall anxiety than offspring of BD parents with the l/l genotype. No significant differences in anxiety symptoms or their association with the 5-HTTLPR genotype were found in the HC group.

CONCLUSIONS

This study indicated that there may be an association between 5-HTTLPR genotypes and anxiety symptoms in offspring of BD parents, and that antianxiety medication status may affect anxiety symptoms in the offspring of BD patients according to genotype.

Short alleles, bigger smiles? The effect of 5-HTTLPR on positive emotional expressions

The present research examined the effect of the 5-HTTLPR polymorphism in the serotonin transporter gene on objectively coded positive emotional expressions (i.e., laughing and smiling behavior objectively coded using the Facial Action Coding System). Three studies with independent samples of participants were conducted. Study 1 examined young adults watching still cartoons. Study 2 examined young, middle-aged, and older adults watching a thematically ambiguous yet subtly amusing film clip. Study 3 examined middle-aged and older spouses discussing an area of marital conflict (that typically produces both positive and negative emotion). Aggregating data across studies, results showed that the short allele of 5-HTTLPR predicted heightened positive emotional expressions. Results remained stable when controlling for age, gender, ethnicity, and depressive symptoms. These findings are consistent with the notion that the short allele of 5-HTTLPR functions as an emotion amplifier, which may confer heightened susceptibility to environmental conditions.

Integrating NIMH Research Domain Criteria (RDoC) into Depression Research

The NIMH Research Domain Criteria (RDoC) initiative grew out of the agency's goal to develop "new ways of classifying mental disorders based on behavioral dimensions and neurobiological measures" (NIMH, 2008). In this article, we review how depression research can be meaningfully conducted within an RDoC framework, with a particular focus on the negative valence systems construct of Loss. New efforts to understand depression within the context of RDoC must seek an integrative understanding of the disorder across multiple units of analysis from genes to neural circuits to behavior. In addition, the constructs or processes must be understood within the context of specific environmental and developmental influences. Key concepts are discussed and we end by highlighting research on rumination as a prime example of research that is consistent with RDoC.

Shame and Guilt-Proneness in Adolescents: Gene-Environment Interactions

Rooted in people’s preoccupation with how they are perceived and evaluated, shame and guilt are self-conscious emotions that play adaptive roles in social behavior, but can also contribute to psychopathology when dysregulated. Shame and guilt-proneness develop during childhood and adolescence, and are influenced by genetic and environmental factors that are little known to date. This study investigated the effects of early traumatic events and functional polymorphisms in the brain-derived neurotrophic factor (BDNF) gene and the serotonin transporter gene promoter (5-HTTLPR) on shame and guilt in adolescents. A sample of N = 271 healthy adolescents between 14 and 17 years of age filled in measures of early traumatic events and proneness to shame and guilt, and were genotyped for the BDNF Val66Met and 5-HTTLPR polymorphisms. Results of moderator analyses indicated that trauma intensity was positively associated with guilt-proneness only in carriers of the low-expressing Met allele of BDNF Val66Met. This is the first study that identifies a gene-environment interaction that significantly contributes to guilt proneness in adolescents, with potential implications for developmental psychopathology.

Adolescent Loneliness and the Interaction between the Serotonin Transporter Gene (5-HTTLPR) and Parental Support: A Replication Study

Gene-by-environment interaction (GxEs) studies have gained popularity over the last decade, but the robustness of such observed interactions has been questioned. The current study contributes to this debate by replicating the only study on the interaction between the serotonin transporter gene (5-HTTLPR) and perceived parental support on adolescents’ peer-related loneliness. A total of 1,111 adolescents (51% boys) with an average age of 13.70 years (SD = 0.93) participated and three annual waves of data were collected. At baseline, adolescent-reported parental support and peer-related loneliness were assessed and genetic information was collected. Assessment of peer-related loneliness was repeated at Waves 2 and 3. Using a cohort-sequential design, a Latent Growth Curve Model was estimated. Overall, a slight increase of loneliness over time was found. However, the development of loneliness over time was found to be different for boys and girls: girls’ levels of loneliness increased over time, whereas boys’ levels of loneliness decreased. Parental support was inversely related to baseline levels of loneliness, but unrelated to change of loneliness over time. We were unable to replicate the main effect of 5-HTTLPR or the 5-HTTLPR x Support interaction effect. In the Discussion, we examine the implications of our non-replication.

Chronic mild stress and antidepressant treatment alter 5-HT1A receptor expression by modifying DNA methylation of a conserved Sp4 site

The serotonin 1A receptor (5-HT1A), a critical regulator of the brain serotonergic tone, is implicated in major depressive disorder (MDD) where it is often found to be dys-regulated. However, the extent to which stress and antidepressant treatment impact 5-HT1A expression in adults remains unclear. To address this issue, we subjected adult male BALB/c mice to unpredictable chronic mild stress (UCMS) to induce a depression-like phenotype that was reversed by chronic treatment with the antidepressant imipramine. In prefrontal cortex (PFC) and midbrain tissue, UCMS increased 5-HT1A RNA and protein levels, changes that are expected to decrease the brain serotonergic activity. The stress-induced increase in 5-HT1A expression was paralleled by a specific increase in DNA methylation of the conserved -681 CpG promoter site, located within a Sp1-like element. We show that the -681 CpG site is recognized and repressed by Sp4, the predominant neuronal Sp1-like factor and that Sp4-induced repression is attenuated by DNA methylation, despite a stress-induced increase in PFC Sp4 levels. These results indicate that adult life stress induces DNA methylation of a conserved promoter site, antagonizing Sp4 repression to increase 5-HT1A expression. Chronic imipramine treatment fully reversed the UCMS-induced increase in methylation of the -681 CpG site in the PFC but not midbrain of stressed animals and also increased 5-HT1A expression in the PFC of control animals. Incomplete reversal by imipramine of stress-induced changes in 5-HT1A methylation and expression indicates a persistence of stress vulnerability, and that sustained reversal of behavioral impairments may require additional pathways.

BDNF Val(66)Met and 5-HTTLPR Genotype are Each Associated with Visual Scanning Patterns of Faces in Young Children

Previous studies have documented both neuroplasticity-related BDNF Val(66)Met and emotion regulation-related 5-HTTLPR polymorphisms as genetic variants that contribute to the processing of emotions from faces. More specifically, research has shown the BDNF Met allele and the 5-HTTLPR Short allele to be associated with mechanisms of negative affectivity that relate to susceptibility for psychopathology. We examined visual scanning pathways in response to angry, happy, and neutral faces in relation to BDNF Val(66)Met and 5-HTTLPR genotyping in 49 children aged 4-7 years. Analyses revealed that variations in the visual processing of facial expressions of anger interacted with BDNF Val(66)Met genotype, such that children who carried at least one low neuroplasticity Met allele exhibited a vigilance-avoidance pattern of visual scanning compared to homozygotes for the high neuroplasticity Val allele. In a separate investigation of eye gaze towards the eye versus mouth regions of neutral faces, we observed that short allele 5-HTTLPR carriers exhibited reduced looking at the eye region compared with those with the higher serotonin uptake Long allele. Together, these findings suggest that genetic mechanisms early in life may influence the establishment of patterns of visual scanning of environmental stressors, which in conjunction with other factors such as negative life events, may lead to psychological difficulties and disorders in the later adolescent and adult years.

Genetics of anxiety disorders: Genetic epidemiological and molecular studies in humans

This review provides a broad overview of the state of research in the genetics of anxiety disorders (AD). Genetic epidemiological studies report a moderate level of familial aggregation (odds ratio: 4-6) and heritability estimates are about 30-50%. Twin studies suggest that the genetic architecture of AD is not isomorphic with their classifications, sharing risk factors with each other. So far, linkage and association studies of AD have produced inconclusive results. Genome-wide association studies of AD can provide an unbiased survey of common genetic variations across the entire genome. Given the shared causes of AD that transcend our current diagnostic classifications, clustering anxiety phenotypes into broader groups may be a powerful approach to identifying susceptibility locus for AD. Using such a shared genetic risk factor, meta-analyses of genome-wide association studies of AD conducted by large consortia are needed. Environmental factors also make a substantial contribution to the cause of AD. Although candidate gene studies of gene by environmental (G × E) interaction have appeared recently, no genome-wide search for G × E interactions have been performed. Epigenetic modification of DNA appears to have important effects on gene expression mediating environmental influences on disease risk. Given that G × E can be linked to an epigenetic modification, a combination analysis of genome-wide G × E interaction and methylation could be an alternative method to find risk variants for AD. This genetic research will enable us to utilize more effective strategies for the prevention and treatment of AD in the near future.

Social support and the serotonin transporter genotype (5-HTTLPR) moderate levels of resilience, sense of coherence, and depression

Gene x environment interactions have mainly been investigated in models of psychopathology. However, the putative interplay between genes and beneficial environmental conditions on positive outcomes has rarely been addressed. We therefore examined the interaction between the serotonin transporter linked polymorphic region (5-HTTLPR) and social support on the sense of coherence (SOC), resilience, and depressive symptoms. Furthermore, we scrutinized our examinations by differentiating between individuals with and without childhood abuse. The sample included 1,811 participants from the general population (Study of Health in Pomerania, Germany). The triallelic genotype of 5-HTTLPR was determined and longitudinal data of social support were used. Among individuals with high social support no significant differences between 5-HTTLPR genotypes regarding all outcome variables were found. However, among those with low social support, carriers of at least one short allele reported significantly increased levels of SOC and resilience, as well as less depressive symptoms than carriers of the l/l genotype. This result was not modified by differentiating between those with childhood abuse and those without. In less supportive social environments the impact of distinct genotypes on behavioral outcomes might be more relevant than in supportive environments where social compensation might take place. Our findings indicate that both alleles of 5-HTTLPR contribute to the adaptability to different environmental conditions.

Psychological Consequences of Early Global Deprivation

The English & Romanian Adoptees (ERA) study follows children who spent their first years of life in extremely depriving Romanian institutions before they were adopted by families in the UK. The ERA study constitutes a “natural experiment” that allows the examination of the effects of radical environmental change from a profoundly depriving institutional environment to an adoptive family home. The cohort has been assessed at ages 4, 6, 11, and 15 years, and has provided seminal insights into the effects of early global deprivation. The current paper focuses on the long-term psychological sequelae associated with deprivation experiences. These deprivation-specific problems (DSPs) constitute a striking pattern of behavioral impairments, in its core characterized by deficits in social cognition and behavior, as well as quasi-autistic features, often accompanied by cognitive impairment and symptoms of attention-deficit/hyperactivity disorder (ADHD). Possible moderating influences, including variations in family environment, pre-adoption characteristics, and genetic variation, will be discussed to answer the question why some individuals have prospered while others have struggled. Apart from findings on the moderating effect of variation in genes associated with serotonergic and dopaminergic signaling involving specific phenotypes, heterogeneity in outcome is largely unexplained. The review concludes with an outlook on currently ongoing and future research of the ERA study cohort, which involves the investigation of neurobiological and epigenetic mechanisms as possible mediators of the long-term effects of institutional deprivation.

Genetic sensitivity to emotional cues, racial discrimination and depressive symptoms among African-American adolescent females

Psychosocial stress, including stress resulting from racial discrimination (RD), has been associated with elevated depressive symptoms. However, individuals vary in their reactivity to stress, with some variability resulting from genetic differences. Specifically, genetic variation within the linked promoter region of the serotonin transporter gene (5-HTTLPR) is related to heightened reactivity to emotional environmental cues. Likewise, variations within this region may interact with stressful life events (e.g., discrimination) to influence depressive symptoms, but this has not been empirically examined in prior studies. The objective of this study was to examine whether variation in the 5-HTTLPR gene interacts with RD to predict depressive symptoms among a sample of African-American adolescent females. Participants were 304 African-American adolescent females enrolled in a sexually transmitted disease prevention trial. Participants completed a baseline survey assessing psychosocial factors including RD (low vs. high) and depressive symptomatology (low vs. high) and provided a saliva sample for genotyping the risk polymorphism 5-HTTLPR (s allele present vs. not present). In a logistic regression model adjusting for psychosocial correlates of depressive symptoms, an interaction between RD and 5-HTTLPR group was significantly associated with depressive symptomatology (AOR = 3.79, 95% CI: 1.20-11.98, p = 0.02). Follow-up tests found that high RD was significantly associated with greater odds of high depressive symptoms only for participants with the s allele. RD and 5-HTTLPR status interact to differentially impact depressive symptoms among African-American adolescent females. Efforts to decrease depression among minority youth should include interventions which address RD and strengthen factors (e.g., coping, emotion regulation, building support systems) which protect youth from the psychological costs of discrimination.

[Depression comorbid to ischemic heart disease: a psychometric and molecular-genetic study]

OBJECTIVE

To compare psychometric and molecular-genetic characteristics of depression caused by ischemic heart disease (IHD) and depression in patients with IHD caused by other psychogenic factors.

MATERIAL AND METHODS

One hundred and thirty-five patients with depression comorbid to ischemic heart disease (IHD) were examined. Depression was associated with IHD in 71 patients (group 1). In 64 patients, depression was caused by other psychogenic factors (group 2). The HAMD-21 scale was used to measure depressive symptoms.

RESULTS AND CONCLUSION

The comparative analysis of the core symptoms of depression demonstrated that group 1 had a peculiar psychometric profile with marked apathy, which was not accompanied by marked hypothymia, guilt feelings or anxiety, compared to group 2. The molecular-genetic correlate of this profile was found. It included a combination of an allele S (5-HTTLPR) of the serotonin transporter gene, an allele G (A-1438G) of the serotonin receptor type 2A gene and the genotype ValVal (Val66Met) of the brain-derived neurotrophic factor gene.

Genetic Variations in the Serotonergic System Mediate a Combined, Weakened Response to SSRI Treatment: A Proposed Model

Individuals with the short (S) allele in the promoter region of the serotonin transporter gene (5-HTTLPR) show a less favorable response to selective serotonin reuptake inhibitor (SSRI) treatment than individuals with the long (L) allele. Similarly, individuals with the C(-1019)G allele for the mutation found in the promoter region of the serotonin 1A receptor gene (5-HTR1A) have shown blunted responses to SSRI treatment when compared with individuals lacking this polymorphism. While these findings have been replicated across multiple studies, only two studies to date have reported data for a gene-gene interaction associated with response to SSRI treatment. Both of these studies reported a combined effect for these genotypes, with individuals homozygous for the L allele and the C allele (5-HTT(L/L)-1A(C/C)) reporting the most favorable response to SSRI treatment, and individuals homozygous for the S allele and the G allele (5-HTT(S/S)-1A(G/G)) reporting the least favorable response to SSRI treatment. Additionally, no neural mechanisms have been proposed to explain why this gene-gene interaction has been observed. To that end, this article provides a review of the relevant literature associated with these polymorphisms and proposes a feasible model that describes a genotype-dependent modulation of postsynaptic serotonin signaling associated with the 5-HTT and 5-HTR1A genes.

Genetic moderation of the association between adolescent romantic involvement and depression: Contributions of serotonin transporter gene polymorphism, chronic stress, and family discord

Studies support a link between adolescent romantic involvement and depression. Adolescent romantic relationships may increase depression risk by introducing chronic stress, and genetic vulnerability to stress reactivity/emotion dysregulation may moderate these associations. We tested genetic moderation of longitudinal associations between adolescent romantic involvement and later depressive symptoms by a polymorphism in the serotonin transporter linked polymorphic region gene (5-HTTLPR) and examined contributory roles of chronic stress and family discord. Three hundred eighty-one youth participated at ages 15 and 20. The results indicated that 5-HTTLPR moderated the association between age 15 romantic involvement and age 20 depressive symptoms, with strongest effects for short homozygotes. Conditional process analysis revealed that chronic stress functioned as a moderated mediator of this association, fully accounting for the romantic involvement-depression link among short/short genotypes. Also, romantic involvement predicted later depressive symptoms most strongly among short-allele carriers with high family discord. The results have important implications for understanding the romantic involvement-depression link and the behavioral and emotional correlates of the 5-HTTLPR genotype.

Can we observe epigenetic effects on human brain function?

Imaging genetics has identified many contributions of DNA sequence variation to individual differences in brain function, behavior, and risk for psychopathology. Recent studies have extended this work beyond the genome by mapping epigenetic differences, specifically gene methylation in peripherally assessed DNA, onto variability in behaviorally and clinically relevant brain function. These data have generated understandable enthusiasm for the potential of such research to illuminate biological mechanisms of risk. We use our research on the effects of genetic and epigenetic variation in the human serotonin transporter on brain function to generate a guardedly optimistic opinion that the available data encourage continued research in this direction, and suggest strategies to promote faster progress.

5-HTTLPR genotype potentiates the effects of war zone stressors on the emergence of PTSD, depressive and anxiety symptoms in soldiers deployed to iraq

Exposure to war zone stressors is common, yet only a minority of soldiers experience clinically meaningful disturbance in psychological function. Identification of biomarkers that predict vulnerability to war zone stressors is critical for developing more effective treatment and prevention strategies not only in soldiers but also in civilians who are exposed to trauma. We investigated the role of the serotonin transporter linked polymorphic region (5-HTTLPR) genotype in predicting the emergence of post-traumatic stress disorder (PTSD), depressive and anxiety symptoms as a function of war zone stressors. A prospective cohort of 133 U.S. Army soldiers with no prior history of deployment to a war zone, who were scheduled to deploy to Iraq, was recruited. Multilevel regression models were used to investigate associations between 5-HTTLPR genotype, level of war zone stressors, and reported symptoms of PTSD, depression and anxiety while deployed to Iraq. Level of war zone stressors was associated with symptoms of PTSD, depression and anxiety. Consistent with its effects on stress responsiveness, 5-HTTLPR genotype moderated the relationship between level of war zone stressors and symptoms of emotional disturbance. Specifically, soldiers carrying one or two low functioning alleles (S or LG ) reported heightened symptoms of PTSD, depression and anxiety in response to increased levels of exposure to war zone stressors, relative to soldiers homozygous for the high functioning allele (LA ). These data suggest that 5-HTTLPR genotype moderates individual sensitivity to war zone stressors and the expression of emotional disturbance including PTSD symptoms. Replication of this association along with identification of other genetic moderators of risk can inform the development of biomarkers that can predict relative resilience vs. vulnerability to stress.

Polygenic risk, stressful life events and depressive symptoms in older adults: a polygenic score analysis

BACKGROUND

Previous studies suggest that the relationship between genetic risk and depression may be moderated by stressful life events (SLEs). The goal of this study was to assess whether SLEs moderate the association between polygenic risk of major depressive disorder (MDD) and depressive symptoms in older adults.

METHOD

We used logistic and negative binomial regressions to assess the associations between polygenic risk, SLEs and depressive symptoms in a sample of 8761 participants from the Health and Retirement Study. Polygenic scores were derived from the Psychiatric Genomics Consortium genome-wide association study of MDD. SLEs were operationalized as a dichotomous variable indicating whether participants had experienced at least one stressful event during the previous 2 years. Depressive symptoms were measured using an eight-item Center for Epidemiologic Studies Depression Scale subscale and operationalized as both a dichotomous and a count variable.

RESULTS

The odds of reporting four or more depressive symptoms were over twice as high among individuals who experienced at least one SLE (odds ratio 2.19, 95% confidence interval 1.86-2.58). Polygenic scores were significantly associated with depressive symptoms (β = 0.21, p ⩽ 0.0001), although the variance explained was modest (pseudo r 2 = 0.0095). None of the interaction terms for polygenic scores and SLEs was statistically significant.

CONCLUSIONS

Polygenic risk and SLEs are robust, independent predictors of depressive symptoms in older adults. Consistent with an additive model, we found no evidence that SLEs moderated the association between common variant polygenic risk and depressive symptoms.

Serotonin transporter polymorphism (5HTTLPR), severe childhood abuse and depressive symptom trajectories in adulthood

BACKGROUND

Cross-sectional studies suggest that the serotonin transporter promoter region polymorphism (5-HTT gene-linked polymorphic region, 5HTTLPR) moderates the relationship between childhood abuse and major depressive disorder.

AIMS

To examine whether the 5HTTLPR polymorphism moderates the effect childhood abuse has on 5-year depressive symptom severity trajectories in adulthood.

METHOD

At 5-year follow-up, DNA from 333 adult primary care attendees was obtained and genotyped for the 5HTTLPR polymorphism. Linear mixed models were used to test for a genotype × childhood abuse interaction effect on 5-year depressive symptom severity trajectories.

RESULTS

After covariate adjustment, homozygous s allele carriers with a history of severe childhood abuse had significantly greater depressive symptom severity at baseline compared with those without a history of severe childhood abuse and this effect persisted throughout the 5-year period of observation.

CONCLUSIONS

The 5HTTLPR s/s genotype robustly moderates the effects of severe childhood abuse on depressive symptom severity trajectories in adulthood.

DECLARATION OF INTEREST

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

I just ran a thousand analyses: benefits of multiple testing in understanding equivocal evidence on gene-environment interactions

BACKGROUND

In psychiatric genetics research, the volume of ambivalent findings on gene-environment interactions (G x E) is growing at an accelerating pace. In response to the surging suspicions of systematic distortion, we challenge the notion of chance capitalization as a possible contributor. Beyond qualifying multiple testing as a mere methodological issue that, if uncorrected, leads to chance capitalization, we advance towards illustrating the potential benefits of multiple tests in understanding equivocal evidence in genetics literature.

METHOD

We focused on the interaction between the serotonin-transporter-linked promotor region (5-HTTLPR) and childhood adversities with regard to depression. After testing 2160 interactions with all relevant measures available within the Dutch population study of adolescents TRAILS, we calculated percentages of significant (p < .05) effects for several subsets of regressions. Using chance capitalization (i.e. overall significance rate of 5% alpha and randomly distributed findings) as a competing hypothesis, we expected more significant effects in the subsets of regressions involving: 1) interview-based instead of questionnaire-based measures; 2) abuse instead of milder childhood adversities; and 3) early instead of later adversities. Furthermore, we expected equal significance percentages across 4) male and female subsamples, and 5) various genotypic models of 5-HTTLPR.

RESULTS

We found differences in the percentages of significant interactions among the subsets of analyses, including those regarding sex-specific subsamples and genetic modeling, but often in unexpected directions. Overall, the percentage of significant interactions was 7.9% which is only slightly above the 5% that might be expected based on chance.

CONCLUSION

Taken together, multiple testing provides a novel approach to better understand equivocal evidence on G x E, showing that methodological differences across studies are a likely reason for heterogeneity in findings - but chance capitalization is at least equally plausible.

Variation in serotonin transporter linked polymorphic region (5-HTTLPR) short/long genotype modulates resting frontal electroencephalography asymmetries in children

Previous studies have documented the serotonin transporter linked polymorphic region (5-HTTLPR) as a genetic susceptibility variant that contributes to variability in outcomes related to affective psychopathology, with the short allele associated with negative affectivity and the long allele associated with positive affectivity. In a separate but related line of research, extensive evidence suggests that frontal electroencephalography (EEG) hemispheric asymmetry in the alpha band is also associated with risk for affective psychopathologies, with leftward asymmetry associated with approach-related behavior patterns and rightward frontal EEG asymmetry associated with withdrawn behavioral tendencies. We examined frontal EEG hemispheric asymmetries in relation to 5-HTTLPR genotyping in 70 children between 4 and 6 years of age. Analyses revealed that frontal EEG lateralization interacted with genotype such that children homozygous for the short allele exhibited rightward frontal EEG asymmetries, children who were homozygous for the long allele consistently exhibited a positive pattern of leftward asymmetry, and heterozygotes exhibited equivalent left and right frontal activity. These findings suggest that the 5-HTTLPR short allele may provide a degree of susceptibility for later affective psychopathology in adolescence and adulthood, through mediation of frontal brain activity that is associated with cognitive-behavioral withdrawal tendencies and negative affectivity.

Influence of life stress, 5-HTTLPR genotype, and SLC6A4 methylation on gene expression and stress response in healthy Caucasian males

Background

Previous research reported that individual differences in the stress response were moderated by an interaction between individuals’ life stress experience and the serotonin transporter-linked polymorphic region (5-HTTLPR), a common polymorphism located in the promoter region of the serotonin transporter gene (SLC6A4). Furthermore, this work suggested that individual differences in SLC6A4 DNA methylation could be one underlying mechanism by which stressful life events might regulate gene expression. The aim of this study was to understand the relation between early and recent life stress experiences, 5-HTTLPR genotype, and SLC6A4 methylation. In addition, we aimed to address how these factors influence gene expression and cortisol response to an acute psychosocial stressor, operationalized as the Trier Social Stress Test (TSST). In a sample of 105 Caucasian males, we collected early and recent life stress measures and blood samples to determine 5-HTTLPR genotype and SLC6A4 methylation. Furthermore, 71 of these participants provided blood and saliva samples before and after the TSST to measure changes in SLC6A4 and NR3C1 gene expression and cortisol response.

Results

Compared to S-group individuals, LL individuals responded with increased SLC6A4 mRNA levels to the TSST (t(66) = 3.71, P < .001) and also showed increased global methylation as a function of ELS (r (32) = .45, P = .008) and chronic stress (r (32) = .44, P = .010). Compared to LL individuals, S-group individuals showed reduced SLC6A4 mRNA levels (r (41) = −.31, P = .042) and increased F3 methylation (r (67) = .30, P = .015) as a function of ELS; as well as increased F1 methylation as a function of chronic stress and recent depressive symptoms (r = .41, P < .01), which correlated positively with NR3C1 expression (r (42) = .31, P = .040).

Conclusions

Both early and recent life stress alter DNA methylation as a function of 5-HTTLPR genotype. Some of these changes are also reflected in gene expression and cortisol response, differentially affecting individuals’ stress response in a manner that may confer susceptibility or resilience for psychopathology upon experiencing stressful life events.

Electronic supplementary material

The online version of this article (doi:10.1186/s13587-015-0017-x) contains supplementary material, which is available to authorized users.

Voxel-based, brain-wide association study of aberrant functional connectivity in schizophrenia implicates thalamocortical circuitry

BACKGROUND

Wernicke's concept of 'sejunction' or aberrant associations among specialized brain regions is one of the earliest hypotheses attempting to explain the myriad of symptoms in psychotic disorders. Unbiased data mining of all possible brain-wide connections in large data sets is an essential first step in localizing these aberrant circuits.

METHODS

We analyzed functional connectivity using the largest resting-state neuroimaging data set reported to date in the schizophrenia literature (415 patients vs. 405 controls from UK, USA, Taiwan, and China). An exhaustive brain-wide association study at both regional and voxel-based levels enabled a continuous data-driven discovery of the key aberrant circuits in schizophrenia.

RESULTS

Results identify the thalamus as the key hub for altered functional networks in patients. Increased thalamus-primary somatosensory cortex connectivity was the most significant aberration in schizophrenia (P=10(-18)). Overall, a number of thalamic links with motor and sensory cortical regions showed increased connectivity in schizophrenia, whereas thalamo-frontal connectivity was weakened. Network changes were correlated with symptom severity and illness duration, and support vector machine analysis revealed discrimination accuracies of 73.53-80.92%.

CONCLUSIONS

Widespread alterations in resting-state thalamocortical functional connectivity is likely to be a core feature of schizophrenia that contributes to the extensive sensory, motor, cognitive, and emotional impairments in this disorder. Changes in this schizophrenia-associated network could be a reliable mechanistic index to discriminate patients from healthy controls.

Interactive effects of citalopram and serotonin transporter genotype on neural correlates of response inhibition and attentional orienting

The brain's serotonergic (5-HT) system has been implicated in controlling impulsive behavior and attentional orienting and linked to impulse control and anxiety related disorders. However, interactions between genotypical variation and responses to serotonergic drugs impede both treatment efficacy and neuroscientific research. We examine behavioral and electrophysiological responses to acute intravenous administration of a selective serotonin reuptake inhibitor (SSRI) while controlling for major genetic differences regarding 5-HT transporter (5-HTT) genotypes. Out of a genotyped sample of healthy Caucasian subjects (n=878) two extreme-groups regarding 5-HTT genotypes were selected (n=32). A homozygous high-expressing group based on tri-allelic 5-HTTLPR and rs25532 (LAC/LAC=LL) was compared to homozygous S allele carriers (SS). Both groups were administered a low dose of citalopram (10mg) intravenously in a double blind crossover fashion and performed a novelty NoGo paradigm while high density EEG was recorded. Interactions between drug and genotype were seen on both behavioral and neurophysiological levels. Reaction slowing following inhibitory events was decreased by the administration of citalopram in the LL but not SS group. This was accompanied by decreases in the amplitude of the inhibitory N2 EEG component and the P3b in the LL group, which was not seen in the SS group. SS subjects showed an increase in P3a amplitudes following SSRI administration to any type of deviant stimulus possibly reflecting increased attentional capture. The acute SSRI response on inhibitory processes and attentional orienting interacts with genotypes regulating 5-HTT gene expression. SS subjects may show increased attentional side effects reflected in increases in P3a amplitudes which could contribute to treatment discontinuation. Inhibitory processes and their neural correlates are affected only in LL subjects. These findings may indicate an underlying mechanism that could relate genotypical differences to altered side effect profiles and drug responses and are compatible with a non-monotonic relationship between 5-HT levels and optimal functioning.

The effects of the interplay of genetics and early environmental risk on the course of internalizing symptoms from late childhood through adolescence

Internalizing symptoms during adolescence and beyond is a major public health concern, particularly because severe symptoms can lead to the diagnosis of a number of serious psychiatric conditions. This study utilizes a unique sample with a complex statistical method in order to explore Gene × Environment interactions found in internalizing symptoms during adolescence. Data for this study were drawn from a longitudinal prevention intervention study (n = 798) of Baltimore city school children. Internalizing symptom data were collected using self-report and blood or saliva samples genotyped using Affymetrix 6.0 microarrays. A major depression polygenic score was created for each individual using information from the major depressive disorder Psychiatric Genetics Consortium and used as a predictor in a latent trait-state-occasion model. The major depressive disorder polygenic score was a significant predictor of the stable latent trait variable, which captures time-independent phenotypic variability. In addition, an early childhood stressor of death or divorce was a significant predictor of occasion-specific variables. A Gene × Environment interaction was not a significant predictor of the latent trait or occasion variables. These findings support the importance of genetics on the stable latent trait portion of internalizing symptoms across adolescence.

The association between the 5-HTTLPR and neural correlates of fear conditioning and connectivity

Strong evidence links the 5-HTTLPR genotype to the modulation of amygdala reactivity during fear conditioning, which is considered to convey the increased vulnerability for anxiety disorders in s-allele carriers. In addition to amygdala reactivity, the 5-HTTLPR has been shown to be related to alterations in structural and effective connectivity. The aim of this study was to investigate the effects of 5-HTTLPR genotype on amygdala reactivity and effective connectivity during fear conditioning, as well as structural connectivity [as measured by diffusion tensor imaging (DTI)]. To integrate different classification strategies, we used the bi-allelic (s-allele vs l/l-allele group) as well as the tri-allelic (low-functioning vs high-functioning) classification approach. S-allele carriers showed exaggerated amygdala reactivity and elevated amygdala-insula coupling during fear conditioning (CS + > CS-) compared with the l/l-allele group. In addition, DTI analysis showed increased fractional anisotropy values in s-allele carriers within the uncinate fasciculus. Using the tri-allelic classification approach, increased amygdala reactivity and amygdala insula coupling were observed in the low-functioning compared with the high-functioning group. No significant differences between the two groups were found in structural connectivity. The present results add to the current debate on the influence of the 5-HTTLPR on brain functioning. These differences between s-allele and l/l-allele carriers may contribute to altered vulnerability for psychiatric disorders.

Are there common familial influences for major depressive disorder and an overeating-binge eating dimension in both European American and African American female twins?

OBJECTIVE

Although prior studies have demonstrated that depression is associated with an overeating-binge eating dimension (OE-BE) phenotypically, little research has investigated whether familial factors contribute to the co-occurrence of these phenotypes, especially in community samples with multiple racial/ethnic groups. We examined the extent to which familial (i.e., genetic and shared environmental) influences overlapped between Major Depressive Disorder (MDD) and OE-BE in a population-based sample and whether these influences were similar across racial/ethnic groups.

METHOD

Participants included 3,226 European American (EA) and 550 African American (AA) young adult women from the Missouri Adolescent Female Twin Study. An adaptation of the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) was administered to assess lifetime DSM-IV MDD and OE-BE. Quantitative genetic modeling was used to estimate familial influences between both phenotypes; all models controlled for age.

RESULTS

The best-fitting model, which combined racial/ethnic groups, found that additive genetic influences accounted for 44% (95% CI: 34%, 53%) of the MDD variance and 40% (25%, 54%) for OE-BE, with the remaining variances due to non-shared environmental influences. Genetic overlap was substantial (rg  = .61 [.39, .85]); non-shared environmental influences on MDD and OE-BE overlapped weakly (re  = .26 [.09, .42]).

DISCUSSION

Results suggest that common familial influences underlie MDD and OE-BE, and the magnitude of familial influences contributing to the comorbidity between MDD and OE-BE is similar between EA and AA women. If racial/ethnic differences truly exist, then larger sample sizes may be needed to fully elucidate familial risk for comorbid MDD and OE-BE across these groups.

EFFECT OF THE APOE ε4 ALLELE AND COMBAT EXPOSURE ON PTSD AMONG IRAQ/AFGHANISTAN-ERA VETERANS

BACKGROUND

The apolipoprotein E (APOE) ε4 allele has been implicated in a range of neuropsychiatric conditions. The present research examined if the ε4 allele of the APOE gene moderated the effect of combat exposure on posttraumatic stress disorder (PTSD) among Iraq/Afghanistan-era veterans.

METHOD

Participants included 765 non-Hispanic White (NHW) and 859 non-Hispanic Black (NHB) Iraq/Afghanistan-era veterans. A structured interview established psychiatric diagnoses. Combat exposure and PTSD symptom severity were assessed via self-report.

RESULTS

The most common lifetime diagnoses were depression (39.2%), PTSD (38.4%), and alcohol dependence (24.38%). After correcting for multiple comparisons, no significant effects were observed on any of the outcomes among the NHW sample; however, within the NHB sample, significant gene × environment (G × E) interactions were observed for lifetime PTSD (P = .0029) and PTSD symptom severity (P = .0009). In each case, the APOE ε4 allele had no effect on the outcomes when combat exposure was low; however, when combat exposure was high, an additive effect was observed such that ε4 homozygotes exposed to high levels of combat reported the highest rates of PTSD (92%) and the worst symptom severity scores on the Davidson Trauma Scale (M = 79.5).

CONCLUSIONS

Although preliminary, these findings suggest that the APOE ε4 allele, in conjunction with exposure to high levels of combat exposure, may increase veterans' risk for developing PTSD.

Effects of persisting emotional impact from child abuse and norepinephrine transporter genetic variation on antidepressant efficacy in major depression: a pilot study

Objective

Previous studies suggest child abuse and serotonergic polymorphism influence depression susceptibility and anti-depressant efficacy. Polymorphisms of the norepinephrine transporter (NET) may also be involved. Research in the area is possibly clouded by under reporting of abuse in researcher trials.

Methods

Adults (n=51) with major depressive disorder has 8 weeks treatment with escitalopram or venlafaxine. Abuse history was obtained, the ongoing emotional impact of which was measured with the 15-item impact of event scale (IES-15). The 17-item Hamilton Depression Rating Scale (HDRS) was applied serially. Two NET polymorphisms (rs2242446 and rs5569) were assayed, blinded to HDRS ratings and abuse history.

Results

No subjects reporting abuse with high impact in adulthood (IES-15 ≥26, n=12) remitted; whereas 77% reporting low impact (IES-15 <26; n=26) remitted (p<0.001). Subjects reporting high impact abuse (n=12) had a 50-fold (95% confidence interval=4.85–514.6) greater odds of carrying rs2242446-TT genotype, but the small sample size leaves this finding vulnerable to type I error.

Conclusion

The level of persisting impact of child abuse appears relevant to antidepressant efficacy, with susceptibility to such possibly being influence by NET rs2242446 polymorphism. Larger studies may be merited to expand on this pilot level finding given potential for biomarker utility.

Mind the gap: why many geneticists and psychological scientists have discrepant views about gene-environment interaction (G×E) research

As our field seeks to elucidate the biopsychosocial etiologies of mental health disorders, many traditional psychological and social science researchers have added, or plan to add, genetic components to their programs of research. An understanding of the history, methods, and perspectives of the psychiatric genetics community is useful in this pursuit. In this article we provide a brief overview of psychiatric genetic methods and findings. This overview lays the groundwork for a more thorough review of gene-environment interaction (G×E) research and the candidate gene approach to G×E research that remains popular among many psychologists and social scientists. We describe the differences in perspective between psychiatric geneticists and psychological scientists that have contributed to a growing divide between the research cited and conducted by these two related disciplines. Finally, we outline a strategy for the future of research on gene-environment interactions that capitalizes on the relative strengths of each discipline. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Serotonin transporter gene polymorphism (5-HTTLPR) influences trait anxiety by modulating the functional connectivity between the amygdala and insula in Han Chinese males

A functional polymorphism (5-hydroxytryptamine transporter linked polymorphic region [5-HTTLPR]) in the promoter region of human serotonin transporter gene has been found to be associated with several dimensions of neuroticism and psychopathology, especially anxiety. However, the neural basis underlying the association between 5-HTTLPR and anxiety is less clear. Here, we explored how 5-HTTLPR influenced anxiety by modulating the spontaneous brain activities in Han Chinese. First, we found an association between 5-HTTLPR and anxiety only in the male and not in the female population, where male S/S homozygotes had a significantly higher level of anxiety than male L allele carriers. Then, we examined how 5-HTTLPR influenced anxiety at both regional and network levels in the brain at rest. At the regional level, we found a significantly higher fractional amplitude of low-frequency fluctuations in the amygdala in male S/S homozygotes relative to male L allele carriers. At the network level, male S/S homozygotes showed a weaker resting-state functional connectivity (RSFC) between the amygdala and various regions, including the insula, Heschl's gyrus, lateral occipital cortex, superior temporal gyrus, and hippocampus, and a stronger RSFC between the amygdala and various regions, including the supramariginal gyrus and middle frontal gyrus. However, at both levels, only was the amygdala-insula RSFC correlated with anxiety. Mediation analyses further revealed that the amygdala-insula RSFC mediated the association between 5-HTTLPR and anxiety. In short, our study provided the first empirical evidence that the amygdala-insula RSFC served as the neural basis underlying the association between 5-HTTLPR and anxiety, suggesting a potential neurogenetic susceptibility mechanism for anxiety.

Oxytocin receptor gene variation and differential susceptibility to family environment in predicting youth borderline symptoms

Oxytocin appears to be centrally involved in socioemotional functioning, and is hypothesized to be relevant to the severe disruption in close relationships characteristic of borderline personality pathology. We examined whether a polymorphism of the oxytocin receptor gene (OXTR rs53576) interacts with quality of family functioning to predict borderline personality disorder (BPD) symptomatology in a sample of youth at age 20. A total of 385 youth from a longitudinal study of offspring of depressed or nondepressed mothers who were well characterized with respect to their family conditions and BPD symptomatology provided DNA for genotyping. Analyses revealed a significant moderation of the link between early family quality and later BPD symptoms by OXTR rs53576, and the pattern was consistent with differential susceptibility (plasticity). Whereas A-allele carriers had high levels of BPD symptoms under negative family conditions and low levels under positive conditions, GG homozygotes had average levels of BPD symptoms regardless of their family quality.

The nature of individual differences in inhibited temperament and risk for psychiatric disease: A review and meta-analysis

What makes us different from one another? Why does one person jump out of airplanes for fun while another prefers to stay home and read? Why are some babies born with a predisposition to become anxious? Questions about individual differences in temperament have engaged the minds of scientists, psychologists, and philosophers for centuries. Recent technological advances in neuroimaging and genetics provide an unprecedented opportunity to answer these questions. Here we review the literature on the neurobiology of one of the most basic individual differences-the tendency to approach or avoid novelty. This trait, called inhibited temperament, is innate, heritable, and observed across species. Importantly, inhibited temperament also confers risk for psychiatric disease. Here, we provide a comprehensive review of inhibited temperament, including neuroimaging and genetic studies in human and non-human primates. We conducted a meta-analysis of neuroimaging findings in inhibited humans that points to alterations in a fronto-limbic-basal ganglia circuit; these findings provide the basis of a model of inhibited temperament neurocircuitry. Lesion and neuroimaging studies in non-human primate models of inhibited temperament highlight roles for the amygdala, hippocampus, orbitofrontal cortex, and dorsal prefrontal cortex. Genetic studies highlight a role for genes that regulate neurotransmitter function, such as the serotonin transporter polymorphisms (5-HTTLPR), as well as genes that regulate stress response, such as corticotropin-releasing hormone (CRH). Together these studies provide a foundation of knowledge about the genetic and neural substrates of this most basic of temperament traits. Future studies using novel imaging methods and genetic approaches promise to expand upon these biological bases of inhibited temperament and inform our understanding of risk for psychiatric disease.

Looking Forward in Candidate Gene Research: Concerns and Suggestions

Candidate Gene × Environment (cGxE) interaction research holds promise for helping us understand for whom and why environments matter for families and development. In their commentary on our target article (G. L. Schlomer, G. M. Fosco, H. H. Cleveland, D. J. Vandenbergh, & M. E. Feinberg, 2015), J. E. Salvatore and D. M. Dick (2015) present their view of the current state and future of cGxE research and frame the debate regarding its merits for advancing knowledge of gene-environment interplay. In this reply, we discuss points of agreement and departure and provide a list of 5 domains by which the quality of cGxE research should be evaluated. Our hope is that researchers will use this list as a guide for their own work.