FKBP5 as a possible moderator of the psychosis-inducing effects of childhood trauma

Molecular evidence of altered stress responsivity related to neuroinflammation in the schizophrenia midbrain

Stress and inflammation are risk factors for schizophrenia. Chronic psychosocial stress is associated with subcortical hyperdopaminergia, a core feature of schizophrenia. Hyperdopaminergia arises from midbrain neurons, leading us to hypothesise that changes in stress response pathways may occur in this region. To identify whether transcriptional changes in glucocorticoid and mineralocorticoid receptors (NR3C1/GR, NR3C2/MR) or other stress signalling molecules (FKBP4, FKBP5) exist in schizophrenia midbrain, we measured gene expression in the human brain (N = 56) using qRT-PCR. We assessed whether alterations in these mRNAs were related to previously identified high/low inflammatory status. We investigated relationships between stress-related transcripts themselves, and between FKBP5 mRNA, dopaminergic, and glial cell transcripts in diagnostic and inflammatory subgroups. Though unchanged by diagnosis, GR mRNA levels were reduced in high inflammatory compared to low inflammatory schizophrenia cases (p = 0.026). We found no effect of diagnosis or inflammation on MR mRNA. FKBP4 mRNA was decreased and FKBP5 mRNA was increased in schizophrenia (p < 0.05). FKBP5 changes occurred in high inflammatory (p < 0.001), whereas FKBP4 changes occurred in low inflammatory schizophrenia cases (p < 0.05). The decrease in mRNA encoding the main stress receptor (GR), as well as increased transcript levels of the stress-responsive negative regulator (FKBP5), may combine to blunt the midbrain response to stress in schizophrenia when neuroinflammation is present. Negative correlations between FKBP5 mRNA and dopaminergic transcripts in the low inflammatory subgroup suggest higher levels of FKBP5 mRNA may also attenuate dopaminergic neurotransmission in schizophrenia even when inflammation is absent. We report alterations in GR-mediated stress signalling in the midbrain in schizophrenia.

Pathways from threat exposure to psychotic symptoms in youth: The role of emotion recognition bias and brain structure

BACKGROUND

Research supports an association between threatening experiences in childhood and psychosis. It is possible that early threat exposure disrupts the development of emotion recognition (specifically, producing a bias for facial expressions relating to threat) and the brain structures subserving it, contributing to psychosis development.

METHODS

Using data from the Philadelphia Neurodevelopmental Cohort, we examined associations between threat exposure and both the misattribution of facial expressions to fear/anger in an emotion recognition task, and gray matter volumes in key emotion processing regions. Our sample comprised youth with psychosis spectrum symptoms (N = 304), control youth (N = 787), and to evaluate specificity, youth with internalizing symptoms (N = 92). The moderating effects of group and sex were examined.

RESULTS

Both the psychosis spectrum and internalizing groups had higher levels of threat exposure than controls. In the total sample, threat exposure was associated with lower left medial prefrontal cortex (mPFC) volume but not misattributions to fear/anger. The effects of threat exposure did not significantly differ by group or sex.

CONCLUSIONS

The findings of this study provide evidence for an effect of threat exposure on mPFC morphology, but do not support an association between threat exposure and a recognition bias for threat-related expressions, that is particularly pronounced in psychosis. Future research should investigate factors linking transdiagnostic alterations related to threat exposure with psychotic symptoms, and attempt to clarify the mechanisms underpinning emotion recognition misattributions in threat-exposed youth.

Role of FKBP5 and its genetic mutations in stress-induced psychiatric disorders: an opportunity for drug discovery

Stress-induced mental health disorders are affecting many people around the world. However, effective drug therapy for curing psychiatric diseases does not occur sufficiently. Many neurotransmitters, hormones, and mechanisms are essential in regulating the body's stress response. One of the most critical components of the stress response system is the hypothalamus-pituitary-adrenal (HPA) axis. The FKBP prolyl isomerase 51 (FKBP51) protein is one of the main negative regulators of the HPA axis. FKBP51 negatively regulates the cortisol effects (the end product of the HPA axis) by inhibiting the interaction between glucocorticoid receptors (GRs) and cortisol, causing reduced transcription of downstream cortisol molecules. By regulating cortisol effects, the FKBP51 protein can indirectly regulate the sensitivity of the HPA axis to stressors. Previous studies have indicated the influence of FKBP5 gene mutations and epigenetic changes in different psychiatric diseases and drug responses and recommended the FKBP51 protein as a drug target and a biomarker for psychological disorders. In this review, we attempted to discuss the effects of the FKBP5 gene, its mutations on different psychiatric diseases, and drugs affecting the FKBP5 gene.

Genetic and psychosocial stressors have independent effects on the level of subclinical psychosis: findings from the multinational EU-GEI study

AIMS

Gene x environment (G×E) interactions, i.e. genetic modulation of the sensitivity to environmental factors and/or environmental control of the gene expression, have not been reliably established regarding aetiology of psychotic disorders. Moreover, recent studies have shown associations between the polygenic risk scores for schizophrenia (PRS-SZ) and some risk factors of psychotic disorders, challenging the traditional gene v. environment dichotomy. In the present article, we studied the role of GxE interaction between psychosocial stressors (childhood trauma, stressful life-events, self-reported discrimination experiences and low social capital) and the PRS-SZ on subclinical psychosis in a population-based sample.

METHODS

Data were drawn from the EUropean network of national schizophrenia networks studying Gene-Environment Interactions (EU-GEI) study, in which subjects without psychotic disorders were included in six countries. The sample was restricted to European descendant subjects (n = 706). Subclinical dimensions of psychosis (positive, negative, and depressive) were measured by the Community Assessment of Psychic Experiences (CAPE) scale. Associations between the PRS-SZ and the psychosocial stressors were tested. For each dimension, the interactions between genes and environment were assessed using linear models and comparing explained variances of 'Genetic' models (solely fitted with PRS-SZ), 'Environmental' models (solely fitted with each environmental stressor), 'Independent' models (with PRS-SZ and each environmental factor), and 'Interaction' models (Independent models plus an interaction term between the PRS-SZ and each environmental factor). Likelihood ration tests (LRT) compared the fit of the different models.

RESULTS

There were no genes-environment associations. PRS-SZ was associated with positive dimensions (β = 0.092, R² = 7.50%), and most psychosocial stressors were associated with all three subclinical psychotic dimensions (except social capital and positive dimension). Concerning the positive dimension, Independent models fitted better than Environmental and Genetic models. No significant GxE interaction was observed for any dimension.

CONCLUSIONS

This study in subjects without psychotic disorders suggests that (i) the aetiological continuum hypothesis could concern particularly the positive dimension of subclinical psychosis, (ii) genetic and environmental factors have independent effects on the level of this positive dimension, (iii) and that interactions between genetic and individual environmental factors could not be identified in this sample.

Hippocampal volume, FKBP5 genetic risk alleles, and childhood trauma interact to increase vulnerability to chronic multisite musculoskeletal pain

Chronic multisite musculoskeletal pain (CMP) is common and highly morbid. However, vulnerability factors for CMP are poorly understood. Previous studies have independently shown that both small hippocampal brain volume and genetic risk alleles in a key stress system gene, FKBP5, increase vulnerability for chronic pain. However, little is known regarding the relationship between these factors and CMP. Here we tested the hypothesis that both small hippocampal brain volume and FKBP5 genetic risk, assessed using the tagging risk variant, FKBP5rs3800373, increase vulnerability for CMP. We used participant data from 36,822 individuals with available genetic, neuroimaging, and chronic pain data in the UK Biobank study. Although no main effects were observed, the interaction between FKBP5 genetic risk and right hippocampal volume was associated with CMP severity (β = -0.020, p_raw = 0.002, p_adj = 0.01). In secondary analyses, severity of childhood trauma further moderated the relationship between FKBP5 genetic risk, right hippocampal brain volume, and CMP (β = -0.081, p = 0.016). This study provides novel evidence that both FKBP5 genetic risk and childhood trauma moderate the relationship between right hippocampal brain volume and CMP. The data increases our understanding of vulnerability factors for CMP and builds a foundation for further work assessing causal relationships that might drive CMP development.

The Moderating Role of the FKBP5 Gene Polymorphisms in the Relationship between Attachment Style, Perceived Stress and Psychotic-like Experiences in Non-Clinical Young Adults

Numerous studies have reported that stressful life experiences increase the risk of psychosis and psychotic-like experiences (PLEs). Common variations of the FKBP5 gene have been reported to impact the risk of psychosis by moderating the effects of environmental exposures. Moreover, anxious and avoidant attachment styles have been shown to increase both the level of perceived stress and the risk for psychosis development. In the present cross-sectional study, we aimed to investigate whether variants of the FKBP5 gene moderate the effects of attachment styles and the level of perceived stress on the development of PLEs. A total of 535 non-clinical undergraduates were genotyped for six FKBP5 single nucleotide polymorphisms (SNPs) (rs3800373, rs9470080, rs4713902, rs737054, rs1360780 and rs9296158). The Psychosis Attachment Measure (PAM), the Perceived Stress Scale-10 (PSS-10) and the Prodromal Questionnaire 16 (PQ-16) were administered to assess attachment styles, the level of perceived stress and PLEs, respectively. Anxious attachment style, lower levels of perceived self-efficacy and higher levels of perceived helplessness were associated with a significantly higher number of PLEs. The main effects of attachment style on the severity of PLEs were significant in models testing for the associations with perceived self-efficacy and three FKBP5 SNPs (rs1360780, rs9296158 and rs9470080). The main effect of rs38003733 on the number of PLEs was observed, with GG homozygotes reporting a significantly higher number of PLEs in comparison to T allele carriers. In individuals with dominant anxious attachment style, there was a significant effect of the interaction between the FKBP5 rs4713902 SNP and self-efficacy on the severity of PLEs. Among rs4713902 TT homozygotes, a low level of perceived self-efficacy was associated with higher severity of PLEs. In subjects with non-dominant anxious attachment, a low level of perceived self-efficacy was associated with a higher number of PLEs, regardless of the genotype. Our results indicate that the FKBP5 gene might moderate the relationship between attachment, perceived stress and PLEs.

Cortisol Levels in Childhood Associated With Emergence of Attenuated Psychotic Symptoms in Early Adulthood

BACKGROUND

In individuals at clinical high-risk for psychosis, elevated cortisol levels predict subsequent onset of psychotic disorder. However, it is unclear whether cortisol alterations are evident at an earlier clinical stage and promote progression of psychosis expression. This study aimed to address this issue by investigating whether cortisol levels in childhood were associated with the emergence of attenuated psychotic symptoms in early adulthood. In exploratory analyses, we examined whether cortisol and psychosocial stress measures interacted in predicting attenuated psychotic symptoms.

METHODS

A sample of children (N = 109) enriched for psychosis risk factors were recruited at age 9-12 years and assessed at age 11-14 years (T1) and 17-21 years (T2). Measures of psychopathology, psychosocial stressors, and salivary cortisol were obtained at T1. Attenuated psychotic symptoms were assessed at T2 using the Prodromal Questionnaire.

RESULTS

Diurnal cortisol (β = 0.915, 95% CI: 0.062-1.769) and daily stressors (β = 0.379, 95% CI: 0.034-0.723) at T1 were independently associated with total Prodromal Questionnaire scores at T2 after accounting for demographic factors and T1 psychopathology. Exploratory analyses indicated a significant interaction between T1 diurnal cortisol and daily stressors (β = 0.743, 95% CI: 0.081-1.405), with the highest predicted T2 total Prodromal Questionnaire scores occurring when both diurnal cortisol and daily stressors were increased.

CONCLUSIONS

Our findings suggest that daily stressors and elevations in diurnal cortisol in late childhood/early adolescence increases risk for developing attenuated psychotic symptoms. These findings emphasize the importance of assessing environmental and biological risk factors for psychosis during neurodevelopmentally vulnerable time periods.

Need for care, adversity exposure and perceived stress in clinical and healthy voice-hearers

OBJECTIVES

Psychosis, and in particular auditory verbal hallucinations (AVHs), are associated with adversity exposure. However, AVHs also occur in populations with no need for care or distress.

AIMS

This study investigated whether adversity exposure would differentiate clinical and healthy voice-hearers within the context of a 'three-hit' model of vulnerability and stress exposure.

METHODS

Samples of 57 clinical and 45 healthy voice-hearers were compared on the three 'hits': familial risk; adversity exposure in childhood and in adolescence/adulthood.

RESULTS

Clinical voice-hearers showed greater familial risk than healthy voice-hearers, with more family members with a history of psychosis, but not with other mental disorders. The two groups did not differ in their exposure to adversity in childhood [sexual and non-sexual, victimisation; discrimination and socio-economic status (SES)]. Contrary to expectations, clinical voice-hearers did not differ from healthy voice-hearers in their exposure to victimisation (sexual/non-sexual) and discrimination in adolescence/adulthood, but reported more cannabis and substance misuse, and lower SES.

CONCLUSIONS

The current study found no evidence that clinical and healthy voice-hearers differ in lifetime victimisation exposure, suggesting victimisation may be linked to the emergence of AVHs generally, rather than need-for-care. Familial risk, substance misuse and lower SES may be additional risk factors involved in the emergence of need-for-care and distress.

Environmental Risk Factors for Schizophrenia and Bipolar Disorder and Their Relationship to Genetic Risk: Current Knowledge and Future Directions

Schizophrenia (SZ) and bipolar disorder (BD) are severe psychiatric disorders which result from complex interplay between genetic and environmental factors. It is well-established that they are highly heritable disorders, and considerable progress has been made identifying their shared and distinct genetic risk factors. However, the 15-40% of risk that is derived from environmental sources is less definitively known. Environmental factors that have been repeatedly investigated and often associated with SZ include: obstetric complications, infections, winter or spring birth, migration, urban living, childhood adversity, and cannabis use. There is evidence that childhood adversity and some types of infections are also associated with BD. Evidence for other risk factors in BD is weaker due to fewer studies and often smaller sample sizes. Relatively few environmental exposures have ever been examined for SZ or BD, and additional ones likely remain to be discovered. A complete picture of how genetic and environmental risk factors confer risk for these disorders requires an understanding of how they interact. Early gene-by-environment interaction studies for both SZ and BD often involved candidate genes and were underpowered. Larger samples with genome-wide data and polygenic risk scores now offer enhanced prospects to reveal genetic interactions with environmental exposures that contribute to risk for these disorders. Overall, although some environmental risk factors have been identified for SZ, few have been for BD, and the extent to which these account for the total risk from environmental sources remains unknown. For both disorders, interactions between genetic and environmental risk factors are also not well understood and merit further investigation. Questions remain regarding the mechanisms by which risk factors exert their effects, and the ways in which environmental factors differ by sex. Concurrent investigations of environmental and genetic risk factors in SZ and BD are needed as we work toward a more comprehensive understanding of the ways in which these disorders arise.

The Impact of the FKBP5 Gene Polymorphisms on the Relationship between Traumatic Life Events and Psychotic-Like Experiences in Non-Clinical Adults

Common variations of the FKBP5 gene are implicated in psychotic disorders, by modulating the hypothalamic–pituitary–adrenal axis reactivity to stress. It has been demonstrated that some of them might moderate the effects of childhood trauma on psychosis proneness. However, these associations have not been investigated with respect to traumatic life events (TLEs). Therefore, we aimed to explore whether the FKBP5 polymorphisms moderate the effects of TLEs on the level of psychotic-like experiences (PLEs). A total of 535 non-clinical adults were approached for participation, and genotyping of six FKBP5 polymorphisms (rs3800373, rs9470080, rs4713902, rs737054, rs1360780 and rs9296158) was performed. The Prodromal Questionnaire-16 (PQ-16) and the Traumatic Events Checklist (TEC) were administered to assess PLEs and TLEs, respectively. Among the rs1360780 CC homozygotes, a history of physical abuse was associated with significantly higher PQ-16 scores. This difference was not significant in the rs1360780 T allele carriers. Similarly, a history of physical abuse was associated with significantly higher PQ-16 scores in the rs9296158 GG homozygotes but not in the rs9296158 A allele carriers. Finally, emotional neglect was related to significantly higher PQ-16 scores in the rs737054 T allele carriers but not in the rs737054 CC homozygotes. The present study indicates that variation in the FKBP5 gene might moderate the effects of lifetime traumatic events on psychosis proneness.

Gene Expression Meta-Analysis of Cerebellum Samples Supports the FKBP5 Gene-Environment Interaction Model for Schizophrenia

BACKGROUND

One of the most studied molecular models of gene-environment interactions is that of FKBP5, which has been shown to interact with childhood adversity to increase the risk of psychiatric disorders, and has been implicated in schizophrenia. While the model predicts up-regulation of FKBP5, previous brain samples gene expression studies yielded inconsistent results.

METHODS

We performed a systematic gene expression meta-analysis of FKBP5 and NR3C1, a glucocorticoid receptor inhibited by FKBP5, in cerebellum samples of patients with schizophrenia. The gene expression databases GEO, SMRI and those of NIMH were searched, and out of six screened datasets, three were eligible for the meta-analysis (overall 69 with schizophrenia and 78 controls).

RESULTS

We detected up-regulation of FKBP5 and down-regulation of NR3C1 in schizophrenia, and a negative correlation between their expression patterns. Correlation analysis suggested that the detected differential expression did not result from potential confounding factors.

CONCLUSIONS

Our results give significant support to the FKBP5 gene-environment interaction model for schizophrenia, which provides a molecular mechanism by which childhood adversity is involved in the development of the disorder. To explore FKBP5's potential as a therapeutic target, a mapping of its differential expression patterns in different brain regions of schizophrenia patients is needed.

Adverse Childhood Experiences and Methylation of the FKBP5 Gene in Patients with Psychotic Disorders

Altered methylation of the FKBP5 gene has been observed in various mental disorders and attributed to the effects of adverse childhood experiences (ACEs). However, the level of FKBP5 methylation has not been investigated in patients with psychotic disorders. Therefore, in this study we aimed to determine the FKBP5 methylation in patients with psychosis and controls, taking into account the effects of ACEs. Participants were 85 patients with psychotic disorders, including first-episode psychosis (FEP) patients and acutely relapsed schizophrenia (SCZ-AR) patients, as well as 56 controls. The level of four CpG sites at the FKBP5 gene was determined in the peripheral blood leukocytes using pyrosequencing. After controlling for potential confounding factors, the level of FKBP5 methylation at one out of four tested CpG sites was significantly lower in FEP patients compared to other groups of participants. Significant main effects of parental antipathy and sexual abuse on the level of FKBP5 methylation were observed at the differentially methylated CpG site. Participants reporting this category of ACEs had significantly lower levels of FKBP5 methylation at this CpG site. Lower levels of FKBP5 methylation were associated with better cognitive performance and higher functional capacity in patients with psychosis. In controls, lower methylation of FKBP5 was related to worse performance of immediate memory and language skills. Our findings suggest that hypomethylation of the FKBP5 appears at early stages of psychosis and might be associated with a history of ACEs as well as less severe clinical manifestation.

Interaction of both positive and negative daily-life experiences with FKBP5 haplotype on psychosis risk

Background.

There is limited research on the interaction of both positive and negative daily-life environments with stress-related genetic variants on psychotic experiences (PEs) and negative affect (NA) across the extended psychosis phenotype. This study examined whether the FK506 binding protein 51 (FKBP5) variability moderates the association of positive and negative experiences in the moment with PEs and NA in participants with incipient psychosis and their nonclinical counterparts.

Methods.

A total of 233 nonclinical and 86 incipient psychosis participants were prompted for a 1-week period to assess their day-to-day experiences. Participants were genotyped for four FKBP5 single nucleotide polymorphisms (rs3800373, rs9296158, rs1360780, and rs9470080).

Results.

Multilevel analyses indicated that, unlike the risk haplotype, the protective FKBP5 haplotype moderated all the associations of positive experiences with diminished PEs and NA in incipient psychosis compared with nonclinical group.

Conclusions.

Participants with incipient psychosis showed symptomatic improvement when reporting positive appraisals in the interpersonal domain, which suggests that these act as a powerful coping mechanism. The fact that this occurred in daily-life underscores the clinical significance of this finding and pinpoints the importance of identifying protective mechanisms. In addition, results seem to concur with the vantage sensitivity model of gene–environment interaction, which poses that certain genetic variants may enhance the likelihood of benefiting from positive exposures.

Adverse childhood experiences and clinical severity in bipolar disorder and schizophrenia: A transdiagnostic two-step cluster analysis

BACKGROUND

Adverse childhood experiences (ACEs) are risk factors for psychiatric disorders, but evidence about their relationship with clinical severity is limited. We aimed to classify patients according to ACEs and to compare these clusters with regards to the clinical severity.

METHODS

Seventy-four patients with Bipolar Disorder (BD) and 91 patients with a diagnosis within the Schizophrenia Spectrum Disorders (SSDs) were interviewed. The Childhood Experience of Care and Abuse scale (CECA) and the Positive and Negative Symptoms Scale (PANSS) were administered. A two-step cluster analysis was run to identify clusters according to ACEs. PANSS average scores were compared between clusters.

RESULTS

Three clusters emerged; significant differences in ACEs distribution were evident. Cluster 1 was characterized by very low frequency of ACEs. ACEs related to lack of support/isolation were more frequent within Cluster 2, instead ACEs related to abuse/neglect were over represented in Cluster 3. The comparison of PANSS through ANOVA demonstrated that Cluster 3 not only had significantly higher scores in all dimensions than Cluster 1 and 2 but also a higher average number of ACEs.

LIMITATIONS

CECA is a self-report scale and is subject to recall bias.

CONCLUSIONS

Specific ACEs are related to clinical severity among BD and SSD patients. Early life adversities related to abuse and neglect are associated to greater symptomatic severity than those related to lack of support/isolation. Our findings suggest that a history of ACEs could be used to identify patients at higher risk of unfavorable clinical features.

Hair cortisol concentrations as an indicator of potential HPA axis hyperactivation in risk for psychosis

A chronic hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis is assumed to be an important indicator of vulnerability for psychosis. Despite the considerable research on this topic, putative social origins of HPA axis hyperactivation have received little attention in the literature so far. Also, the inconsistency of previous findings calls for new and reliable methods in the assessment of HPA axis activation. To address these issues, we used hair cortisol concentrations as an indicator of chronic HPA axis activation in participants at elevated risk for psychosis (clinical risk: n = 43, familial risk: n = 32) and low-risk controls (n = 35), and assessed its relation with a variety of social stressors. We also tested the interaction effect between social stressors and familial risk status on hair cortisol concentrations (moderation analysis). Participants at elevated risk for psychosis did not show significantly higher hair cortisol concentrations than low-risk controls. However, severe social stressors (child abuse experiences, traumatic events) predicted hair cortisol concentrations in the total sample. This relationship was not significantly moderated by familial risk status (as a marker of genetic risk). The results challenge the assumption that HPA axis hyperactivation is an early vulnerability indicator for psychosis but leave the possibility that it manifests only at more severe risk stages. Furthermore, the findings suggest that acquired experiences contribute to the emergence of HPA axis hyperactivation, which might occur via a gene-environment correlation rather than via a gene-environment interaction.

Genetics of Resilience: Gene-by-Environment Interaction Studies as a Tool to Dissect Mechanisms of Resilience

The identification and understanding of resilience mechanisms holds potential for the development of mechanistically informed prevention and interventions in psychiatry. However, investigating resilience mechanisms is conceptually and methodologically challenging because resilience does not merely constitute the absence of disease-specific risk but rather reflects active processes that aid in the maintenance of physiological and psychological homeostasis across a broad range of environmental circumstances. In this conceptual review, we argue that the principle used in gene-by-environment interaction studies may help to unravel resilience mechanisms on different investigation levels. We present how this could be achieved by top-down designs that start with gene-by-environment interaction effects on disease phenotypes as well as by bottom-up approaches that start at the molecular level. We also discuss how recent technological advances may improve both top-down and bottom-up strategies.

Interactive effects of genetic polymorphisms and childhood adversity on brain morphologic changes in depression

The etiology of depression is characterized by the interplay of genetic and environmental factors and brain structural alteration. Childhood adversity is a major contributing factor in the development of depression. Interactions between childhood adversity and candidate genes for depression could affect brain morphology via the modulation of neurotrophic factors, serotonergic neurotransmission, or the hypothalamus-pituitary-adrenal (HPA) axis, and this pathway may explain the subsequent onset of depression. Childhood adversity is associated with structural changes in the hippocampus, amygdala, anterior cingulate cortex (ACC), and prefrontal cortex (PFC), as well as white matter tracts such as the corpus callosum, cingulum, and uncinate fasciculus. Childhood adversity showed an interaction with the brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism, serotonin transporter-linked promoter region (5-HTTLPR), and FK506 binding protein 51 (FKBP5) gene rs1360780 in brain morphologic changes in patients with depression and in a non-clinical population. Individuals with the Met allele of BDNF Val66Met and a history of childhood adversity had reduced volume in the hippocampus and its subfields, amygdala, and PFC and thinner rostral ACC in a study of depressed patients and healthy controls. The S allele of 5-HTTLPR combined with exposure to childhood adversity or a poorer parenting environment was associated with a smaller hippocampal volume and subsequent onset of depression. The FKBP5 gene rs160780 had a significant interaction with childhood adversity in the white matter integrity of brain regions involved in emotion processing. This review identified that imaging genetic studies on childhood adversity may deepen our understanding on the neurobiological background of depression by scrutinizing complicated pathways of genetic factors, early psychosocial environments, and the accompanying morphologic changes in emotion-processing neural circuitry.

Genomic updates in understanding PTSD

Twin studies as well as more recent genetics-based heritability analyses demonstrate that up to 40 to 50% of the variance in predicting PTSD following trauma is heritable. However, most of the specific gene pathways and mechanism that mediate risk vs. resilience for PTSD following trauma exposure have yet to be elucidated. This review will examine the latest results from large scale Genome-wide association studies as well as other approaches aimed at understanding mechanisms of development of and recovery from PTSD.

Traumatic life event exposure and psychotic-like experiences: A multiple mediation model of cognitive-based mechanisms

Several cognitive mechanisms have been proposed to account for the relationship between exposure to traumatic life events (TLEs) and the entire psychosis spectrum. However, only few of these mechanisms have been empirically tested and those that have been tested have not considered multiple mechanisms simultaneously. The purpose of this study was to examine whether perceived stress, dissociation, negative self-schemas, negative other-schemas, and/or external locus of control mediated the association between TLEs and psychotic-like experiences (PLEs). An undergraduate sample of 945 individuals completed a battery of self-report questionnaires. We found significant indirect effects from TLE exposure to PLEs through perceived stress, dissociation, external locus of control, negative self-schemas, and negative other-schemas. When controlling for comorbid psychological symptoms, only the indirect effect from TLE exposure to PLEs through dissociation continued to be significant. Targeting stress sensitivity, maladaptive schemas, dissociative tendencies, and externalizing attributional styles may prove useful in the amelioration of risk for various psychopathologies (e.g., mood, psychosis) in the aftermath of TLE exposure. Findings underscore the importance of targeting trauma-related cognitions in the prevention or reduction of psychotic-like experiences or disorders.

Child maltreatment and psychosis

This paper reviews the literature on the association between experiences of child abuse and neglect and the development of psychoses. It then explores the premise that psychotic patients with a history of maltreatment may comprise a clinically and biological distinct subgroup. The review demonstrates that there is a growing consensus in the field that experiences of child maltreatment contribute to the onset of psychotic symptoms and psychotic disorders. There is also strong support for the premise that patients with psychotic disorders and histories of child maltreatment have distinct clinical characteristics and unique treatment needs, and emerging preliminary data to suggest psychotic patients with a history of maltreatment may comprise a distinct neurobiological subgroup. The mechanisms by which experiences of child maltreatment confers risk for psychotic disorders remains unknown, and the review highlights the value of incorporating translational research perspectives to advance knowledge in this area.

Association between FKBP5 polymorphisms and depressive disorders or suicidal behavior: A systematic review and meta-analysis study

Psychiatric disorders are complex polygenic diseases that show common genetic vulnerability. Several studies have investigated the association of polymorphisms of FK506 binding protein 51 (FKBP5) gene and depressive disorders or suicidal behavior, however, the results have been controversial and ambiguous. The aim of our study was to explore the role of the FKBP5 gene variants (rs1360780, rs3800373 and rs4713916), in depressive disorders or suicidal behavior through a systematic review and a meta-analysis. The protocol number of the study is PROSPERO CRD42018089295. The meta-analysis included 12 studies. Odds ratios with 95% confidence intervals were used to evaluate the association and the publication bias was tested by Egger's test and funnel plot; heterogeneity was assessed by the Cochran's chi-square-based Q statistic test and the inconsistency index. Our results showed that the rs3800373 and rs4713916 were associated with an increased risk of depressive disorders when using the heterozygous and dominant models. In the stratified analysis by ethnicity, a significantly increased risk of depressive disorders was also observed for rs3800373 and rs4713916 in Caucasians. When we analyzed suicidal behavior, we found a significant association with the rs1360780 of FKBP5 and suicidal behavior risk in the overall population and rs3800373 in completed suicide subgroup. Existing evidence indicates that the polymorphisms of FKBP5 gene are associated with risk of depressive disorders and suicidal behavior. Future studies with larger sample sizes will be necessary to confirm the present results.

Sex differences in the association between childhood adversities and schizotypal personality traits

Patients with psychosis report higher levels of adverse events in childhood. This relationship has not been extensively examined in healthy individuals who score highly on schizotypal personality traits. This study examined the association between different childhood traumas and psychosis-like traits in a general population sample, as well as differences in those links between men and women. Participants completed an online survey including measures of physical, emotional, and sexual abuse, and schizotypal personality traits. Results showed that the experience of emotional abuse was associated with a range of both positive and negative psychosis-like traits in both sexes. Sex differences emerged in the association between physical abuse and schizotypal personality traits. Although men reported more physical abuse in early life than women, this type of trauma was only associated with schizotypal traits in women and not in men. Additionally, women scored higher than men in sexual abuse; however, sexual abuse did not explicitly predict any schizotypal traits in the presence of the other two types of abuse. A simple linear or dose-response relationship between different types of trauma and psychosis-like traits was not supported. The importance of emotional abuse on schizotypy was highlighted in both sexes.

Associations Between Gene Polymorphisms and Psychological Stress in the Guangxi Minority Region of China

To investigate whether there is an association between gene polymorphisms, genetic and environmental interactions, and psychological stress reactivity in Chinese subjects living in the Guangxi minority region. This cross-sectional study enrolled subjects older than 18 years, living in Nandan county, Guangxi minority region, China for at least 1 year. All participants were healthy, without any mental diseases, and were able to communicate. Eligible participants were randomly selected. The Life Event Scale Questionnaire, Simplified Coping Style Questionnaire, and Social Support Rating Scale were used to measure the physiological stress, coping style, and social support, respectively, in individuals. A total of 600 participants were recruited. A decreased risk of psychological stress was only found in TT of NPSR1 (rs324981): A allele carriers vs. TT genotype (OR 1.64, 95% CI 1.11, 2.42), and AT genotype vs. TT genotype (OR 1.76, 95% CI 1.17, 2.65). The overall coping style was positively associated with psychological stress, and no significant interactions between genetics and environment were found. We found that the NPSR1 (rs324981) T/T genotype decreased the risk of psychological stress, while the overall coping style was a risk factor for psychological stress. However, there was no interactive effects of genes and environment on psychological stress. Our findings will improve understanding of the biological basis underlying psychological stress if the results can be replicated in further research.

Gene-environment interplay in the etiology of psychosis

Schizophrenia and other types of psychosis incur suffering, high health care costs and loss of human potential, due to the combination of early onset and poor response to treatment. Our ability to prevent or cure psychosis depends on knowledge of causal mechanisms. Molecular genetic studies show that thousands of common and rare variants contribute to the genetic risk for psychosis. Epidemiological studies have identified many environmental factors associated with increased risk of psychosis. However, no single genetic or environmental factor is sufficient to cause psychosis on its own. The risk of developing psychosis increases with the accumulation of many genetic risk variants and exposures to multiple adverse environmental factors. Additionally, the impact of environmental exposures likely depends on genetic factors, through gene-environment interactions. Only a few specific gene-environment combinations that lead to increased risk of psychosis have been identified to date. An example of replicable gene-environment interaction is a common polymorphism in the AKT1 gene that makes its carriers sensitive to developing psychosis with regular cannabis use. A synthesis of results from twin studies, molecular genetics, and epidemiological research outlines the many genetic and environmental factors contributing to psychosis. The interplay between these factors needs to be considered to draw a complete picture of etiology. To reach a more complete explanation of psychosis that can inform preventive strategies, future research should focus on longitudinal assessments of multiple environmental exposures within large, genotyped cohorts beginning early in life.

Sensorimotor gating deficits in "two-hit" models of schizophrenia risk factors

Genetic and environmental models of neuropsychiatric disease have grown exponentially over the last 20years. One measure that is often used to evaluate the translational relevance of these models to human neuropsychiatric disease is prepulse inhibition of startle (PPI), an operational measure of sensorimotor gating. Deficient PPI characterizes several neuropsychiatric disorders but has been most extensively studied in schizophrenia. It has become a useful tool in translational neuropharmacological and molecular genetics studies because it can be measured across species using almost the same experimental parameters. Although initial studies of PPI in rodents were pharmacological because of the robust predictive validity of PPI for antipsychotic efficacy, more recently, PPI has become standard common behavioral measures used in genetic and neurodevelopmental models of schizophrenia. Here we review "two hit" models of schizophrenia and discuss the utility of PPI as a tool in phenotyping these models of relevant risk factors. In the review, we consider approaches to rodent models of genetic and neurodevelopmental risk factors and selectively review "two hit" models of gene×environment and environment×environment interactions in which PPI has been measured.

Interactions Between Variation in Candidate Genes and Environmental Factors in the Etiology of Schizophrenia and Bipolar Disorder: a Systematic Review

Schizophrenia and bipolar disorder (BD) are complex and multidimensional disorders with high heritability rates. The contribution of genetic factors to the etiology of these disorders is increasingly being recognized as the action of multiple risk variants with small effect sizes, which might explain only a minor part of susceptibility. On the other site, numerous environmental factors have been found to play an important role in their causality. Therefore, in recent years, several studies focused on gene × environment interactions that are believed to bridge the gap between genetic underpinnings and environmental insults. In this article, we performed a systematic review of studies investigating gene × environment interactions in BD and schizophrenia spectrum phenotypes. In the majority of studies from this field, interacting effects of variation in genes encoding catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF), and FK506-binding protein 5 (FKBP5) have been explored. Almost consistently, these studies revealed that polymorphisms in COMT, BDNF, and FKBP5 genes might interact with early life stress and cannabis abuse or dependence, influencing various outcomes of schizophrenia spectrum disorders and BD. Other interactions still require further replication in larger clinical and non-clinical samples. In addition, future studies should address the direction of causality and potential mechanisms of the relationship between gene × environment interactions and various categories of outcomes in schizophrenia and BD.

Interaction between FKBP5 variability and recent life events in the anxiety spectrum: Evidence for the differential susceptibility model

Background

Gene-environment interaction (GxE) research has highlighted the importance of investigating the FK506 binding protein 51 (FKBP5) gene as a sensitivity gene. However, previous GxE studies with FKBP5 have not measured the full environmental spectrum or applied statistical tests to discern whether the GxE interaction fits better with the differential-susceptibility or diathesis-stress hypotheses. This study examined whether single nucleotide polymorphisms (SNPs) on FKBP5 gene moderate the association of positive and negative recent life events (LEs) with depressive symptoms, state-anxiety, neuroticism, and social anxiety traits.

Methods

A total of 86 nonclinical young adults were administered psychological measures and were genotyped for five FKBP5 SNPs (rs3800373, rs9296158, rs1360780, rs9470080 and rs4713916).

Results

Regression analyses indicated significant GxE interactions for social anxiety and neuroticism. The interactions predicting neuroticism fit different models for different SNPs, although the overall effect indicated by the haplotype was consistent with the differential-susceptibility hypothesis: the risk-haplotype group presented higher neuroticism in the presence of more negative LEs and lower neuroticism in the presence of more positive LEs. The GxE interactions for social anxiety were consistent with the diathesis-stress model. The lack of significance in the for-better side for social anxiety might be related to the fact that it mapped onto low extraversion, which is associated with a lower permeability to positive experiences.

Discussion

Findings underscore the importance of testing the differential-susceptibility model in relation to FKBP5 to adequately characterize its role in healthy and pathological developmental processes.

The immune system and schizophrenia: an update for clinicians

It has long been recognised that the pathology of schizophrenia may involve the immune system, yet this has been a relatively neglected area of research. Recent advances in our understanding of the complexities and functioning of the immune system have allowed new investigation into this area from many angles, including cellular and genetic avenues. A number of prominent theories have been developed. This article gives an overview of our understanding of the immune system and highlights recent advances pertaining to schizophrenia.

LEARNING OBJECTIVES

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Bullying victimisation and psychosis: The interdependence and independence of risk trajectories

A number of studies have noted an association between being the victim of bullying and psychotic symptoms. We offer an overview of the topic, focusing especially on a developmental perspective. We highlight the results of the latest studies on psychosis across the continuum and its relationship with bullying. Then we summarise the three main explanatory models investigated: developmental, biological and cognitive. We recommend that bullying in psychosis requires careful study of the developmental trajectories involved, and that research should now focus on how personal, social and biological factors interact.

LEARNING OBJECTIVES

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Interaction between early-life stress and FKBP5 gene variants in major depressive disorder and post-traumatic stress disorder: A systematic review and meta-analysis

BACKGROUND

Gene-environment interaction contributes to the risks of psychiatric disorders. Interactions between FKBP5 gene variants and early-life stress may enhance the risk not only for mood disorder, but also for a number of other behavioral phenotypes. The aim of the present study was to review and conduct a meta-analysis on the results from published studies examining interaction between FKBP5 gene variants and early-life stress and their associations with stress-related disorders such as major depression and PTSD.

METHODS

A literature search was conducted using PsychINFO and PubMed databases until May 2017. A total of 14 studies with a pooled total of 15109 participants met the inclusion criteria, the results of which were combined and a meta-analysis was performed using the differences in correlations as the effect measure. Based on literature, rs1360780, rs3800373, and rs9470080 SNPs were selected within the FKBP5 gene and systematic review was conducted.

RESULTS

Based on the Comprehensive Meta-Analysis software, no publication bias was detected. Sensitivity analysis and credibility of meta-analysis results also indicated that the analyses were stable. The meta-analysis showed that individuals who carry T allele of rs1360780, C-allele of rs3800373 or T-allele of rs9470080 exposed to early-life trauma had higher risks for depression or PTSD.

LIMITATIONS

The effects of ethnicity, age, sex, and different stress measures were not examined due to limited sample size.

CONCLUSIONS

These results provide strong evidence of interactions between FKBP5 genotypes and early-life stress, which could pose a significant risk factor for stress-associated disorders such as major depression and PTSD.

Interaction between FKBP5 gene and childhood trauma on psychosis, depression and anxiety symptoms in a non-clinical sample

BACKGROUND

Childhood trauma has been associated with a heightened risk for presenting clinical and non-clinical psychopathology in adulthood. Genes related with the stress response, such as the FK506 binding protein 51 (FKBP5), are plausible candidates moderating the effects of childhood trauma on the emergence of such symptoms later on. The present study aimed to explore the moderating role of FKBP5 genetic variability on the association of different types of childhood trauma with subclinical psychosis, depression and anxiety in a non-clinical sample.

METHODS

Schizotypy, psychotic-like experiences, depression and anxiety symptoms and childhood trauma were assessed in 808 young adults. Two FKBP5 haplotypic blocks were detected: block 1 (rs3800373 - rs9296158 - rs1360780) and block 2 (rs9470080 - rs4713916). Subjects were classified in two groups according to whether they carried or not the risk haplotype previously described in the literature (block 1: CAT and block 2: TA). Linear regression analyses were used to study (i) the main effects of childhood trauma and FKBP5 haplotype blocks and (ii) their interaction effects on the mentioned forms of psychopathology.

RESULTS

All childhood trauma scales, except sexual abuse, were associated with schizotypy, psychotic-like experiences, depression and anxiety symptoms. None of the analysed symptoms was associated with the main effects of FKBP5 genetic variability. However an interaction effect between block 1 and physical abuse was observed on anxiety, with lower scores in CAT carriers. This effect was driven by SNP 1 and 2. Moreover, an interaction effect between block 2 and physical abuse was identified on the variables tapping depressive and anxiety symptoms. Specifically, non-TA carrier subjects who were exposed to physical abuse were found to be at higher risk for depressive and anxiety symptoms. These effects were driven by SNP 5. No interaction effect was observed for the other variables.

CONCLUSIONS

Our data suggest that exposure to childhood physical abuse may increase the risk for sub-clinical depressive and anxiety symptoms depending on FKBP5 genetic variability. Further research is needed to better elucidate the role of FKBP5 on mental health in clinical and non-clinical cohorts.

Gene-environment interaction as a predictor of early adjustment in first episode psychosis

BACKGROUND

This study aims to explore the gene-environment interaction hypothesis applied to pre-symptomatic neurodevelopmental phenotypes of first episode psychosis (FEP), that is, genetic factors might increase vulnerability to the effects of environmental adverse conditions occurring at later stages of development.

METHODS

We constructed a schematic 'two-hit' model, with Val/Val homozygosity for the catechol-O-methyltransferase (COMT) Val158Met polymorphism as the 'first hit' and history of obstetric complications and parental socioeconomic status as 'second hits'. Early adjustment, measured using the Premorbid Adjustment Scale, was considered the main outcome. The study population comprised 221 adolescents and adults with FEP and 191 sex- and age-matched controls.

RESULTS

The interaction between the Val/Val COMT genotype and a positive history of obstetric complications plus low parental socioeconomic status was significantly associated with poorer early adjustment. These results were observed both in FEP individuals and in controls, and remained significant after controlling for age, sex, and diagnosis.

CONCLUSIONS

Individuals carrying Val/Val seem to be more sensitive to the synergistic effect of environmental factors acting early in neurodevelopment, which leads to vulnerability phenotypes such as impaired early adjustment.

The role of stress-regulation genes in moderating the association of stress and daily-life psychotic experiences

OBJECTIVE

The interaction of single nucleotide polymorphisms with both distal and proximal environmental factors across the extended psychosis phenotype is understudied. This study examined (i) the interaction of relevant SNPs with both early-life adversity and proximal (momentary) stress on psychotic experiences (PEs) in an extended psychosis sample; and (ii) differences between early-psychosis and non-clinical groups for these interactions.

METHODS

Two hundred and forty-two non-clinical and 96 early-psychosis participants were prompted randomly eight times daily for 1 week to complete assessments of current experiences, including PEs and stress. Participants also reported on childhood trauma and were genotyped for 10 SNPs on COMT, RGS4, BDNF, FKBP5, and OXTR genes.

RESULTS

Unlike genetic variants, distal and proximal stressors were associated with PEs in both samples and were more strongly associated with PEs in the early-psychosis than in the non-clinical group. The RGS4 TA and FKBP5 CATT haplotypes interacted with distal stress, whereas the A allele of OXTR (rs2254298) interacted with proximal stress, increasing momentary levels of PEs in the early-psychosis group. No interactions emerged with COMT or BDNF variants.

CONCLUSION

Individual differences in relevant stress-regulation systems interact with both distal and proximal psychosocial stressors in shaping the daily-life manifestation of PEs across the psychosis continuum.

The emerging role of the FKBP5 gene polymorphisms in vulnerability-stress model of schizophrenia: further evidence from a Serbian population

Increased reactivity to stress is observed in patients with schizophrenia spectrum disorders and their healthy siblings in comparison with the general population. Additionally, higher levels of neuroticism, as a proposed psychological measure of stress sensitivity, increase the risk of schizophrenia. HPA axis dysregulation is one of the possible mechanisms related to the vulnerability-stress model of schizophrenia, and recent studies revealed a possible role of the functional genetic variants of FK506-binding protein 51 (FKBP5) gene which modulate activity of HPA axis. The purpose of the present study was to investigate impact of FKBP5 on schizophrenia in Serbian patients and to explore relationship between genetic variants and neuroticism by using the case-sibling-control design. In 158 subjects, we measured psychotic experiences, childhood trauma and neuroticism. Nine single-nucleotide polymorphisms (rs9295158, rs3800373, rs9740080, rs737054, rs6926133, rs9380529, rs9394314, rs2766533 and rs12200498) were genotyped. The genetic influence was modeled using logistic regression, and the relationship between genetic variants and neuroticism was assessed by linear mixed model. Our results revealed genetic main effect of FKBP5 risk alleles (A allele of rs9296158 and T allele of rs3800373) and AGTC "risk" haplotype combination (rs9296158, rs3800373, rs9470080 and rs737054, respectively) on schizophrenia, particularly when childhood trauma was set as a confounding factor. We confirmed strong relationship between neuroticism and psychotic experiences in patients and siblings and further showed relationship between higher levels of neuroticism and FKBP5 risk variants suggesting potential link between biological and psychosocial risk factors. Our data support previous findings that trauma exposure shapes FKBP5 impact on schizophrenia.

Neurobiological Development in the Context of Childhood Trauma

Neurobiological systems may be particularly susceptible to deleterious impact of childhood trauma, and the impact of childhood trauma on development and subsequent functional outcomes across the lifespan has been well-documented. The current review addresses the neurobiological impact of exposure to interpersonal trauma in childhood in the context of executive function, emotion regulation, and dissociation/interoceptive awareness. Subsequent risk for PTSD and depression is also discussed. The pathway of risk from childhood trauma to these cognitive, emotional, and psychiatric outcomes is addressed in terms of potential structural and functional alterations within the hippocampus, prefrontal cortex, and amygdala resulting from chronic or repeated activation of the hypothalamic-pituitary-adrenal (HPA) axis and its interaction with and influence on genetic and epigenetic processes during sensitive periods of development. Implications for practice are discussed.

Theranostic Biomarkers for Schizophrenia

Schizophrenia is a highly heritable, chronic, severe, disabling neurodevelopmental brain disorder with a heterogeneous genetic and neurobiological background, which is still poorly understood. To allow better diagnostic procedures and therapeutic strategies in schizophrenia patients, use of easy accessible biomarkers is suggested. The most frequently used biomarkers in schizophrenia are those associated with the neuroimmune and neuroendocrine system, metabolism, different neurotransmitter systems and neurotrophic factors. However, there are still no validated and reliable biomarkers in clinical use for schizophrenia. This review will address potential biomarkers in schizophrenia. It will discuss biomarkers in schizophrenia and propose the use of specific blood-based panels that will include a set of markers associated with immune processes, metabolic disorders, and neuroendocrine/neurotrophin/neurotransmitter alterations. The combination of different markers, or complex multi-marker panels, might help in the discrimination of patients with different underlying pathologies and in the better classification of the more homogenous groups. Therefore, the development of the diagnostic, prognostic and theranostic biomarkers is an urgent and an unmet need in psychiatry, with the aim of improving diagnosis, therapy monitoring, prediction of treatment outcome and focus on the personal medicine approach in order to improve the quality of life in patients with schizophrenia and decrease health costs worldwide.

GNB3 and CREB1 gene polymorphisms combined with negative life events increase susceptibility to major depression in a Chinese Han population

BACKGROUND

Major depression (MD) is caused by a combination of genetic and environmental factors. In this study we investigated the interaction of variations in the G-protein beta 3 subunit (GNB3) and cAMP response element binding protein 1 (CREB1) genes with negative life events in the pathogenesis of MD. One GNB3 polymorphism (rs5443) and four CREB1 polymorphisms (rs2253206, rs2551941, rs6740584, rs11904814) were investigated based on known associations with MD.

METHODS

512 patients with MD and 513 control subjects were genotyped. The frequency and severity of negative life events were measured by the Life Events Scale (LES). Gene-environment interactions (G×E) were assessed using the generalized multifactor dimensionality reduction (GMDR) method.

RESULTS

Differences in GNB3 rs5443 allele frequencies and genotype distributions were observed between MD patients and controls. Significant G×E interactions were detected between negative life events and genotypic variation of all five single nucleotide polymorphisms (SNPs). Individuals carrying the T- allele of rs5443 (CC), A- allele of rs2253206 (GG), T- allele of rs2551941 (AA), C- allele of rs6740584 (TT) or G- allele of rs11904814 (TT) conferred susceptibility to MD in subjects only exposed to high-negative life events. However, individuals with the T+ allele of rs5443 (CT, TT) were susceptible to MD when exposed to low negative life events.

CONCLUSIONS

Interactions between GNB3, CREB1 and negative life events were revealed. Further evidence is provided about the role of the environment in genetic vulnerability to MD.

Toward a unified theory of childhood trauma and psychosis: A comprehensive review of epidemiological, clinical, neuropsychological and biological findings

There is a growing body of research focused on the relationship between childhood trauma and the risk of developing psychosis. Numerous studies, including many large-scale population-based studies, controlling for possible mediating variables, provide persuasive evidence of a dose-response association and are indicative of a causal relationship. Existing evidence supports the specificity model, showing differential associations between particular adversities and clinical symptoms, with cumulative adversity causing less favorable clinical and functional outcomes in psychotic patients. To date, several psychological and biological models have been proposed to search for underlying developmental trajectories leading to the onset of psychosis, influencing psychopathological manifestation and negative functional outcomes due to a history of childhood trauma. In this article, we provide a unified review on the relationship between childhood trauma and psychosis by integrating results of epidemiological, clinical, neuropsychological and biological studies. The question whether psychosis with a positive history of childhood trauma should be considered as a new psychotic phenotype, requiring specific therapeutic interventions, warrants further investigation.

Childhood trauma, BDNF Val66Met and subclinical psychotic experiences. Attempt at replication in two independent samples

Childhood trauma exposure is a robust environmental risk factor for psychosis. However, not all exposed individuals develop psychotic symptoms later in life. The Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism (rs6265) has been suggested to moderate the psychosis-inducing effects of childhood trauma in clinical and nonclinical samples. Our study aimed to explore the interaction effect between childhood trauma and the BDNF Val66Met polymorphism on subclinical psychotic experiences (PEs). This was explored in two nonclinical independent samples: an undergraduate and technical-training school student sample (n = 808, sample 1) and a female twin sample (n = 621, sample 2). Results showed that childhood trauma was strongly associated with positive and negative PEs in nonclinical individuals. A BDNF Val66Met x childhood trauma effect on positive PEs was observed in both samples. These results were discordant in terms of risk allele: while in sample 1 Val allele carriers, especially males, were more vulnerable to the effects of childhood trauma regarding PEs, in sample 2 Met carriers presented higher PEs scores when exposed to childhood trauma, compared with Val carriers. Moreover, in sample 2, a significant interaction was also found in relation to negative PEs. Our study partially replicates previous findings and suggests that some individuals are more prone to develop PEs following childhood trauma because of a complex combination of multiple factors. Further studies including genetic, environmental and epigenetic factors may provide insights in this field.

The interactive effects of child maltreatment and the FK506 binding protein 5 gene (FKBP5) on dissociative symptoms in adolescence

The FK506 binding protein 5 gene (FKBP5) has been associated with susceptibility to pathogenic effects of childhood trauma including dissociative symptoms. This study examines the impact of maltreatment on dissociative tendencies in adolescence as moderated by the FKBP5 gene. Dissociative symptoms and variation within FKBP5 were assessed in a high-risk, low socioeconomic status community sample of 279 maltreated and 171 nonmaltreated adolescents. Following the assignment of haplotypes across four single nucleotide polymorphisms (rs3800373, rs9296158, rs1360780, and rs9470080), individuals with one or more copies of the CATT haplotype (N = 230) were grouped together and compared to individuals with zero copies of this haplotype (N = 185). Analyses of covariance were conducted to test hypotheses regarding the effects of developmental timing and the chronicity of maltreatment and the CATT haplotype. We found a significant interactive effect of timing/chronicity of maltreatment and the CATT haplotype on dissociative symptoms. Among adolescents who had no copies of the CATT haplotype, dissociative symptoms were higher for chronically maltreated adolescents who had an infancy onset compared to those who were not maltreated or whose maltreatment experience was either relatively less chronic or not started in infancy. The groups did not differ significantly among subjects who carry one or more copies of the CATT haplotype.

Influence of interactions between genes and childhood trauma on refractoriness in psychiatric disorders

Psychiatric disorders are excellent disease models in which gene-environmental interaction play a significant role in the pathogenesis. Childhood trauma has been known as a significant environmental factor in the progress of, and prognosis for psychiatric illness. Patients with refractory illness usually have more severe symptoms, greater disability, lower quality of life and are at greater risk of suicide than other psychiatric patients. Our literature review uncovered some important clinical factors which modulate response to treatment in psychiatric patients who have experienced childhood trauma. Childhood trauma seems to be a critical determinant of treatment refractoriness in psychotic disorder, bipolar disorder, major depressive disorder, and post-traumatic stress disorder. In patients with psychotic disorders, the relationship between childhood trauma and treatment-refractoriness appears to be mediated by cognitive impairment. In the case of bipolar disorder, the relationship appears to be mediated by greater affective disturbance and earlier onset, while in major depressive disorder the mediating factors are persistent, severe symptoms and frequent recurrence. In suicidal individuals, childhood maltreatment was associated with violent suicidal attempts. In the case of PTSD patients, it appears that childhood trauma makes the brain more vulnerable to subsequent trauma, thus resulting in more severe, refractory symptoms. Given that several studies have suggested that there are distinct subtypes of genetic vulnerability to childhood trauma, it is important to understand how gene-environment interactions influence the course of psychiatric illnesses in order to improve therapeutic strategies.

Interplay between Schizophrenia Polygenic Risk Score and Childhood Adversity in First-Presentation Psychotic Disorder: A Pilot Study

A history of childhood adversity is associated with psychotic disorder, with an increase in risk according to number or severity of exposures. However, it is not known why only some exposed individuals go on to develop psychosis. One possibility is pre-existing genetic vulnerability. Research on gene-environment interaction in psychosis has primarily focused on candidate genes, although the genetic effects are now known to be polygenic. This pilot study investigated whether the effect of childhood adversity on psychosis is moderated by the polygenic risk score for schizophrenia (PRS). Data were utilised from the Genes and Psychosis (GAP) study set in South London, UK. The GAP sample comprises 285 first-presentation psychosis cases and 256 unaffected controls with information on childhood adversity. We studied only white subjects (80 cases and 110 controls) with PRS data, as the PRS has limited predictive ability in patients of African ancestry. The occurrence of childhood adversity was assessed with the Childhood Experience of Care and Abuse Questionnaire (CECA.Q) and the PRS was based on genome-wide meta-analysis results for schizophrenia from the Psychiatric Genomics Consortium. Higher schizophrenia PRS and childhood adversities each predicted psychosis status. Nevertheless, no evidence was found for interaction as departure from additivity, indicating that the effect of polygenic risk scores on psychosis was not increased in the presence of a history of childhood adversity. These findings are compatible with a multifactorial threshold model in which both genetic liability and exposure to environmental risk contribute independently to the etiology of psychosis.

Trauma and the psychosis spectrum: A review of symptom specificity and explanatory mechanisms

Traumatic life events have been robustly associated with various psychosis outcomes, including increased risk of psychotic disorders, the prodrome of psychosis, and dimensional measures of psychotic symptoms, such as attenuated positive psychotic symptoms. However, trauma exposure has been linked to various mental disorders; therefore, the specificity of trauma exposure to psychosis remains unclear. This review focuses on two understudied areas of the trauma and psychosis literature: 1) the specificity between trauma and psychosis in relation to other disorders that often result post-trauma, and 2) proposed mechanisms that uniquely link trauma to psychosis. We begin by discussing the underlying connection between trauma exposure and the entire psychosis spectrum with a focus on the influence of trauma type and specific psychotic symptoms. We then consider how the principles of multifinality and equifinality can be useful in elucidating the trauma-psychosis relationship versus the trauma-other disorder relationship. Next, we discuss several cognitive and neurobiological mechanisms that might uniquely account for the association between trauma and psychosis, as well as the role of gender. Lastly, we review important methodological issues that complicate the research on trauma and psychosis, ending with clinical implications for the field.

The Interaction between Childhood Bullying and the FKBP5 Gene on Psychotic-Like Experiences and Stress Reactivity in Real Life

AIM

The present study employed Experience Sampling Methodology to examine whether the interaction between childhood bullying and FKBP5 variability (i) is associated with the expression of psychotic-like experiences, paranoia, and negative affect, and (ii) moderates psychotic-like, paranoid, and affective reactivity to different forms of momentary stress (situational and social) in daily life.

METHODS

A total of 206 nonclinical young adults were interviewed for bullying with the Childhood Experience of Care and Abuse and were prompted randomly eight times daily for one week to complete assessments of their current experiences, affect, and stress appraisals. Participants were genotyped for three FKBP5 single nucleotide polymorphisms (SNPs) (rs3800373, rs9296158, and rs1360780) that have been linked to hypothalamus-pituitary-adrenal axis reactivity. Multilevel analyses were conducted to examine the effect of the interaction between childhood bullying and the FKBP5 haplotype derived from these three SNPs.

RESULTS

The interaction between bullying and the FKBP5 haplotype was associated with positive, but not negative, psychotic-like experiences, paranoia, and negative affect. The bullying x FKBP5 interaction also moderated the association of a social stress appraisal (specifically, being alone because people do not want to be with you) with psychotic-like experiences and negative affect in daily life. Simple slopes analyses indicated that, in all cases, the associations were significantly increased by exposure to bullying in participants with the risk haplotype, but not for those with the non-risk haplotype.

DISCUSSION

The present study provides the first evidence of the interplay between childhood bullying and FKBP5 variability in the real-world expression of psychosis proneness and social stress reactivity. The findings underscore the importance of investigating how gene-environment interactions are involved in mechanistic pathways to the extended psychosis phenotype and lend further support to the increasing relevance given to socially defeating appraisals in the experience of reality distortion.

Childhood adversities and psychosis: evidence, challenges, implications

There is a substantial body of research reporting evidence of associations between various forms of childhood adversity and psychosis, across the spectrum from experiences to disorder. This has been extended, more recently, to include studies of cumulative effects, of interactions with other factors, of specific effects, and of putative biological and psychological mechanisms. In this paper we evaluate this research and highlight the remaining methodological issues and gaps that temper, but do not dismiss, conclusions about the causal role of childhood adversity. We also consider the emerging work on cumulative, synergistic, and specific effects and on mechanisms; and discuss the broader implications of this line of research for our understanding of psychosis. We conclude that the current balance of evidence is that childhood adversities - particularly exposure to multiple adversities involving hostility and threat - do, in some people, contribute to the onset of psychotic experiences and psychotic disorders.

Pilot study of adrenal steroid hormones in hair as an indicator of chronic mental and physical stress

Currently, the quantitative analysis of moderators affecting the function of the hypothalamus-pituitary-adrenal (HPA)-axis in health and sickness is still unreliable. This is, in particular, due to physiological factors such as pulsatile ultradian and circadian glucocorticoid secretion as well as to methodological limitations of the current techniques for steroid hormone determination. Based on this background, the determination of long-term hair steroid concentrations is an important methodological improvement allowing for the quantitative analysis of chronic HPA axis-activation. In order to determine the relationship between chronic mental and physical stress and a chronic activation of the HPA axis, we performed a cross-sectional pilot-study with 40 healthy students and examined the relationships between physical activity, mental burden(s), subjective stress perceptions, depressiveness, anxiety, physical complaints, sense of coherence, resilience, and the long-term integrated steroid hormone levels in hair. The results showed that the concentrations of cortisol, cortisone, and dehydroepiandrosterone in hair were significantly correlated to mental (p = 0.034) and physical stress (p = 0.001) as well as to subjective stress perception (p = 0.006). We conclude that steroid concentrations in hair are decisive predictors for an increase in the long-term-HPA axis activity. Moreover, this biomarker is suitable for capturing the stresslevel after burdening events and physical activity.

Gene-Stress-Epigenetic Regulation of FKBP5: Clinical and Translational Implications

Stress responses and related outcomes vary markedly across individuals. Elucidating the molecular underpinnings of this variability is of great relevance for developing individualized prevention strategies and treatments for stress-related disorders. An important modulator of stress responses is the FK506-binding protein 51 (FKBP5/FKBP51). FKBP5 acts as a co-chaperone that modulates not only glucocorticoid receptor activity in response to stressors but also a multitude of other cellular processes in both the brain and periphery. Notably, the FKBP5 gene is regulated via complex interactions among environmental stressors, FKBP5 genetic variants, and epigenetic modifications of glucocorticoid-responsive genomic sites. These interactions can result in FKBP5 disinhibition that has been shown to contribute to a number of aberrant phenotypes in both rodents and humans. Consequently, FKBP5 blockade may hold promise as treatment intervention for stress-related disorders, and recently developed selective FKBP5 blockers show encouraging results in vitro and in rodent models. Although risk for stress-related disorders is conferred by multiple environmental and genetic factors, the findings related to FKBP5 illustrate how a deeper understanding of the molecular and systemic mechanisms underlying specific gene-environment interactions may provide insights into the pathogenesis of stress-related disorders.

Psychiatric symptoms in adolescents: FKBP5 genotype--early life adversity interaction effects

Psychiatric disorders are multi-factorial and their symptoms overlap. Constitutional and environmental factors influence each other, and this contributes to risk and resilience in mental ill-health. We investigated functional genetic variation of stress responsiveness, assessed as FKBP5 genotype, in relation to early life adversity and mental health in two samples of adolescents. One population-based sample of 909 12-year-old adolescents was assessed using the Life Incidence of Traumatic Events scale and the Strengths and Difficulties Questionnaire. One sample of 398 17-year-old adolescents, enriched for poly-victimized individuals (USSS), was assessed using the Juvenile Victimization Questionnaire and the Trauma Symptom Checklist for Children (TSCC). The FKBP5 rs1360780 and rs3800373 polymorphisms were genotyped using a fluorescence-based competitive allele-specific PCR. Most prominently among poly-victimized older male adolescents, the least common alleles of the polymorphisms, in interaction with adverse life events, were associated with psychiatric symptoms, after controlling for ethno-socio-economic factors. The interaction effect between rs3800373 and adverse life events on the TSCC sub-scales-anxiety, depression, anger, and dissociation-and with the rs1360780 on dissociation in the USSS cohort remained significant after Bonferroni correction. This pattern of association is in line with the findings of clinical and neuroimaging studies, and implies interactive effects of FKBP5 polymorphisms and early life environment on several psychiatric symptoms. These correlates add up to provide constructs that are relevant to several psychiatric symptoms, and to identify early predictors of mental ill-health.