BDNF val66met modulates the association between childhood trauma, cognitive and brain abnormalities in psychoses

Exploring the impact of childhood maltreatment on epigenetic and brain-derived neurotrophic factor changes in bipolar disorder and healthy control

Childhood maltreatment may be linked to epigenetics and brain-derived neurotrophic factor (BDNF) changes, which are mechanisms altered in several psychiatric conditions, including bipolar disorder (BD). However, the specific mechanisms connecting childhood maltreatment to the pathophysiology of BD remain unclear. The present study aims to examine the effects of childhood maltreatment on epigenetic and neurotrophic outcomes in BD patients and health controls. History of childhood maltreatment was obtained using the Childhood Trauma Questionnaire (CTQ) from 36 BD outpatients and 46 healthy subjects. DNA methyltransferase (DNMT) activity, HMTH3K9 activity, histone 3 lysine 9 tri-methylation (H3K9me3) levels, histone deacetylase (HDAC)1 levels, HDAC2 levels, histone 3 lysine 14 acetylation (H3K14ac) levels, and mRNA of BDNF were evaluated in peripheral blood mononuclear cells. Plasma BDNF levels were also measured. Total scores of CTQ, as well as the subscale scores of emotional abuse, sexual abuse, and emotional neglect, were predictive of changes in DNMT and HMTh3k9 activity, H3K9m3 levels, BDNF mRNA expression, and BDNF levels. These findings were observed in all our samples and, in some cases, among BD patients. Emotional abuse was the main childhood maltreatment subtype associated with epigenetic alterations in BD. Our results elucidate some mechanisms by which childhood maltreatment can alter epigenetic and neurotrophic markers. Especially in BD subjects, our results suggest childhood maltreatment per se is not a direct cause for epigenetic alterations. In another way, we suppose that the effect of childhood maltreatment could be cumulative and interact with other factors associated with the pathophysiology of BD.

DNA methylation at birth and lateral ventricular volume in childhood: a neuroimaging epigenetics study

BACKGROUND

Lateral ventricular volume (LVV) enlargement has been repeatedly linked to schizophrenia; yet, what biological factors shape LVV during early development remain unclear. DNA methylation (DNAm), an essential process for neurodevelopment that is altered in schizophrenia, is a key molecular system of interest.

METHODS

In this study, we conducted the first epigenome-wide association study of neonatal DNAm in cord blood with LVV in childhood (measured using T1-weighted brain scans at 10 years), based on data from a large population-based birth cohort, the Generation R Study (N = 840). Employing both probe-level and methylation profile score (MPS) approaches, we further examined whether epigenetic modifications identified at birth in cord blood are: (a) also observed cross-sectionally in childhood using peripheral blood DNAm at age of 10 years (Generation R, N = 370) and (b) prospectively associated with LVV measured in young adulthood in an all-male sample from the Avon Longitudinal Study of Parents and Children (ALSPAC, N = 114).

RESULTS

At birth, DNAm levels at four CpGs (annotated to potassium channel tetramerization domain containing 3, KCTD3; SHH signaling and ciliogenesis regulator, SDCCAG8; glutaredoxin, GLRX) prospectively associated with childhood LVV after genome-wide correction; these genes have been implicated in brain development and psychiatric traits including schizophrenia. An MPS capturing a broader epigenetic profile of LVV - but not individual top hits - showed significant cross-sectional associations with LVV in childhood in Generation R and prospectively associated with LVV in early adulthood within ALSPAC.

CONCLUSIONS

This study finds suggestive evidence that DNAm at birth prospectively associates with LVV at different life stages, albeit with small effect sizes. The prediction of MPS on LVV in a childhood sample and an independent male adult sample further underscores the stability and reproducibility of DNAm as a potential marker for LVV. Future studies with larger samples and comparable time points across development are needed to further elucidate how DNAm associates with this clinically relevant brain structure and risk for neuropsychiatric disorders, and what factors explain the identified DNAm profile of LVV at birth.

Positive or negative environmental modulations on human brain development: the morpho-functional outcomes of music training or stress

In the last couple of decades, the study of human living brain has benefitted of neuroimaging and non-invasive electrophysiological techniques, which are particularly valuable during development. A number of studies allowed to trace the usual stages leading from pregnancy to adult age, and relate them to functional and behavioral measurements. It was also possible to explore the effects of some interventions, behavioral or not, showing that the commonly followed pathway to adulthood may be steered by external interventions. These events may result in behavioral modifications but also in structural changes, in some cases limiting plasticity or extending/modifying critical periods. In this review, we outline the healthy human brain development in the absence of major issues or diseases. Then, the effects of negative (different stressors) and positive (music training) environmental stimuli on brain and behavioral development is depicted. Hence, it may be concluded that the typical development follows a course strictly dependent from environmental inputs, and that external intervention can be designed to positively counteract negative influences, particularly at young ages. We also focus on the social aspect of development, which starts in utero and continues after birth by building social relationships. This poses a great responsibility in handling children education and healthcare politics, pointing to social accountability for the responsible development of each child.

The neural, stress hormone and inflammatory correlates of childhood deprivation and threat in psychosis: A systematic review

Childhood adversity increases the risk of developing psychosis, but the biological mechanisms involved are unknown. Disaggregating early adverse experiences into core dimensions of deprivation and threat may help to elucidate these mechanisms. We therefore systematically searched the literature investigating associations between deprivation and threat, and neural, immune and stress hormone systems in individuals on the psychosis spectrum. Our search yielded 74 articles, from which we extracted and synthesized relevant findings. While study designs were heterogeneous and findings inconsistent, some trends emerged. In psychosis, deprivation tended to correlate with lower global cortical volume, and some evidence supported threat-related variation in prefrontal cortex morphology. Greater threat exposure was also associated with higher C-reactive protein, and higher and lower cortisol measures. When examined, associations in controls were less evident. Overall, findings indicate that deprivation and threat may associate with partially distinct biological mechanisms in the psychosis spectrum, and that associations may be stronger than in controls. Dimensional approaches may help disentangle the biological correlates of childhood adversity in psychosis, but more studies are needed.

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.

The relationship between genetic liability, childhood maltreatment, and IQ: findings from the EU-GEI multicentric case-control study

This study investigated if the association between childhood maltreatment and cognition among psychosis patients and community controls was partially accounted for by genetic liability for psychosis. Patients with first-episode psychosis (N = 755) and unaffected controls (N = 1219) from the EU-GEI study were assessed for childhood maltreatment, intelligence quotient (IQ), family history of psychosis (FH), and polygenic risk score for schizophrenia (SZ-PRS). Controlling for FH and SZ-PRS did not attenuate the association between childhood maltreatment and IQ in cases or controls. Findings suggest that these expressions of genetic liability cannot account for the lower levels of cognition found among adults maltreated in childhood.

Associations of BDNF/BDNF-AS SNPs with Depression, Schizophrenia, and Bipolar Disorder

Brain-Derived Neurotrophic Factor (BDNF) is crucial for various aspects of neuronal development and function, including synaptic plasticity, neurotransmitter release, and supporting neuronal differentiation, growth, and survival. It is involved in the formation and preservation of dopaminergic, serotonergic, GABAergic, and cholinergic neurons, facilitating efficient stimulus transmission within the synaptic system and contributing to learning, memory, and overall cognition. Furthermore, BDNF demonstrates involvement in neuroinflammation and showcases neuroprotective effects. In contrast, BDNF antisense RNA (BDNF-AS) is linked to the regulation and control of BDNF, facilitating its suppression and contributing to neurotoxicity, apoptosis, and decreased cell viability. This review article aims to comprehensively overview the significance of single nucleotide polymorphisms (SNPs) in BDNF/BDNF-AS genes within psychiatric conditions, with a specific focus on their associations with depression, schizophrenia, and bipolar disorder. The independent influence of each BDNF/BDNF-AS gene variation, as well as the interplay between SNPs and their linkage disequilibrium, environmental factors, including early-life experiences, and interactions with other genes, lead to alterations in brain architecture and function, shaping vulnerability to mental health disorders. The potential translational applications of BDNF/BDNF-AS polymorphism knowledge can revolutionize personalized medicine, predict disease susceptibility, treatment outcomes, and guide the selection of interventions tailored to individual patients.

Childhood trauma relates to worse memory functioning in bipolar disorder

BACKGROUND

Childhood trauma is commonly experienced by individuals diagnosed with bipolar disorder (BP). In BP, childhood trauma is related to a more severe clinical course, but its association with cognition remains unclear.

METHODS

This study evaluated 405 adult participants diagnosed with BP and 136 controls. Participants completed the Childhood Trauma Questionnaire and a comprehensive neuropsychological battery. High versus low childhood trauma was defined with one standard deviation above the control participant's mean Childhood Trauma Questionnaire score. Neuropsychological data was transformed into eight cognitive factors, including four executive functioning, auditory and visual memory, fine motor, and emotion processing. Multivariate analysis of covariance evaluated group differences in cognition, while adjusting for covariates.

RESULTS

There were significant differences among the three groups, F(16, 968) = 4.05, p < .001, Wilks' Λ = 0.88, partial η² = 0.06. Comparing the high and low trauma BP groups, high trauma was related to lower auditory and visual memory factor scores (p < .05). As compared to controls, the BP high trauma group had lower scores on six of eight factors (all p < .01), while the BP low trauma group had lower scores on four of eight factors (all p < .01).

LIMITATIONS

Analyses of factor score do not address which aspect of the memory process is affected and biomarkers may help guide interventions addressing underlying biological process.

CONCLUSIONS

Adults diagnosed with BP with higher childhood trauma have worse memory functioning, beyond the lower childhood trauma BP group, highlighting the importance of understanding the long-term cognitive outcomes of childhood trauma.

The interaction of the oxytocin receptor gene and child abuse subtypes on social cognition in euthymic patients with bipolar disorder type I

Background

Most studies on cognitive impairment in bipolar disorder have neglected the role of early stress, despite the high frequency of childhood maltreatment in this clinical group. The aim of this study was to establish a connection between a history of emotional, physical, and sexual abuse in childhood and social cognition (SC) in patients with bipolar disorder type I (BD-I) in euthymia, and to test a possible moderating effect of the single nucleotide polymorphism rs53576 in the oxytocin receptor gene (OXTR).

Methods

One hundred and one participants were included in this study. History of child abuse was evaluated using the Childhood Trauma Questionnaire-Short Form. Cognitive functioning was appraised using The Awareness of Social Inference Test (social cognition). The interaction effect between the independent variables OXTR rs53576 (AA/AG and GG) and the absence or presence of any one type of child maltreatment or a combination of types was analyzed using a generalized linear model regression.

Results

BD-I patients who had been victims of physical and emotional abuse in childhood and were carriers of the GG genotype at OXTR rs53576 displayed greater SC alterations, specifically in emotion recognition.

Discussion

This gene-environment interaction finding suggests a differential susceptibility model of a genetic variants that can be plausibly associated with SC functioning and might help to identify at-risk clinical subgroups within a diagnostic category. Future research aimed at testing the interlevel impact of early stress constitutes an ethical-clinical duty given the high rates of childhood maltreatment reported in BD-I patients.

Neurotrophic factors, childhood trauma and psychiatric disorders: A systematic review of genetic, biochemical, cognitive and imaging studies to identify potential biomarkers

BACKGROUND

Exposure to traumatic experience represents one of the key environmental factors influencing the risk for several psychiatric disorders, in particular when suffered during childhood, a critical period for brain development, characterized by a high level of neuroplasticity. Abnormalities affecting neurotrophic factors might play a fundamental role in the link between childhood trauma (CT) and early life stress (ELS) and psychiatric disorders.

METHODS

A systematic review was conducted, considering genetic, biochemical and expression studies along with cognitive and brain structure imaging investigations, based on PubMed and Web of Science databases (available up until November 2021), to identify potential neuroplasticity related biomarkers associated both with CT/ELS and psychiatric disorders. The search was followed by data abstraction and study quality assessment (Newcastle-Ottawa Scale).

RESULTS

103 studies met our eligibility criteria. Among them, 65 were available for genetic, 30 for biochemical and 3 for mRNA data; 45 findings were linked to specific symptomatology/pathologies, 16 with various cognitive functions, 19 with different brain areas, 6 on methylation and 36 performed on control subjects for the Brain Derived Neurotrophic Factor (BDNF); whereas 4 expression/biochemical studies covered Neurotrophin 4 (NT-4), Vascular Endothelium Growth Factor (VEGF), Epidermal Growth Factor (EGF), Fibroblast Growth Factor (FGF), and Transforming Growth Factor β1 (TGF-β1).

LIMITATIONS

Heterogeneity of assessments (biological, psychological, of symptomatology, and CT/ELS), age range and ethnicity of samples for BDNF studies; limited studies for other neurotrophins.

CONCLUSIONS

Results support the key role of BDNF (in form of Met allele) as biomarker, both at genetic and biochemical level, in mediating the effect of CT/ELS in psychiatric disorders, passing through specific cognitive functions and specific brain region architecture.

Childhood trauma is associated with poorer social functioning in severe mental disorders both during an active illness phase and in remission

BACKGROUND

Impaired social functioning is a core feature of schizophrenia spectrum (SZS) and bipolar spectrum disorders (BDS). Childhood traumatic events are more frequent in SZS and BDS than in healthy individuals (HC), and could represent a cumulative risk for reduced social functioning beyond experiencing ongoing clinical symptoms.

METHODS

The study comprised 1039 individuals (SZS [n = 348]; BDS [n = 262], and HC [n = 429]). Childhood trauma and level of social functioning was assessed by the Childhood Trauma Questionnaire (CTQ) and the Social Functioning Scale (SFS), respectively. Diagnosis was obtained by the Structured Clinical Interview (SCID) for the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV).

RESULTS

Patients had poorer social functioning (F = 819.18, p ˂ 0.001, Cohen's d = 0.44) and reported more childhood trauma experiences than HC (X² = 289.0, p < .001) than HC. Patients with at least one moderate to severe trauma had poorer social functioning than patients without childhood trauma (F = 8.16, p = .004, Cohen's d = 0.17). Within the patients, a cumulative relationship was observed in that more severe childhood trauma was associated with lower social functioning (F = 2.65, p = .02, Cohen's d = 0.20). No significant associations were observed for having at least one moderate to severe trauma or cumulative traumas on social functioning in the HC. Follow-up analysis showed that patients in remission childhood trauma also had poorer social functioning.

CONCLUSION

Patients who reported childhood trauma experiences had poorer social functioning both during an active illness phase and in remission.

Looking for factors affecting functioning in euthymic patients with bipolar I disorder: the importance of cognitive complaints and BDNF's Val66Met polymorphism

INTRODUCTION

Functioning in Bipolar Disorder (BD) is affected in a substantial proportion of patients. The impact of demographic, clinical, cognitive, and genetic factors on functioning has been shown individually; however, as a complex phenomenon, a global approach to identify the most relevant as well as possible interactions is needed.

METHODS

102 patients with type I BD in euthymia were invited for evaluation of demographic, clinical, and cognitive characteristics as well as genotype for Val66Met polymorphism of BDNF gene to determine those associated with poor functioning according to the FAST scale cut-off score. Clinical evaluation included assessment of residual affective symptoms and anxiety. Cognitive evaluation included the COBRA scale, verbal memory, and executive functions testing.

RESULTS

Residual depressive symptoms, anxiety, cognitive complaints and being a Met carrier were more frequent in the poor functioning group and were entered in a logistic regression model. Being a Met carrier (OR=4.46, CI=1.19-16.67) and cognitive complaints (OR=1.29, CI= 1.13-1.46) were the most important predictors of poor functioning in type I BD.

LIMITATIONS

Cross-sectional study, with select population limiting generalizability of findings.

CONCLUSIONS

A better understanding of underlying factors affecting cognition, including the possible involvement of BDNF Val66Met polymorphism, its systematic evaluation and a continued search for targeted treatment, along with recognition and attention of residual affective and anxious symptoms might improve psychosocial outcomes such as functioning in this population.

Childhood adversities and bipolar disorder: a neuroimaging focus

Early-life adverse events or childhood adversities (CAs) are stressors and harmful experiences severely impacting on a child's wellbeing and development. Examples of CAs include parental neglect, emotional and physical abuse and bullying. Even though the prevalence of CAs and their psychological effects in both healthy and psychiatric populations is established, only a paucity of studies have investigated the neurobiological firms associated with CAs in bipolar disorder (BD). In particular, the exact neural mechanisms and trajectories of biopsychosocial models integrating both environmental and genetic effects are still debated. Considering the potential impact of CAs on BD, including its clinical manifestations, we reviewed existing literature discussing the association between CAs and brain alterations in BD patients. Results showed that CAs are associated with volume alterations of several grey matter regions including the hippocampus, thalamus, amygdala and frontal cortex. A handful of studies suggest the presence of alterations in the corpus callosum and the pre-fronto-limbic connectivity at rest. Alterations in these regions of the brain of patients with BD are possibly due to the effect of stress produced by CAs, being hippocampus part of the hypothalamus-pituitary-adrenal axis and thalamus together with amygdala filtering sensory information and regulating emotional responses. However, results are mixed possibly due to the heterogeneity of methods and study design. Future neuroimaging studies disentangling between different types of CAs or differentiating between BD sub-types are needed in order to understand the link between CAs and BD.

A Meta-Analysis of Brain-Derived Neurotrophic Factor Effects on Brain Volume in Schizophrenia: Genotype and Serum Levels

AIM

The Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene has established pleiotropic effects on schizophrenia incidence and morphologic alterations in the illness. The effects of brain-derived neurotrophic factor (BDNF) on brain volume measurements are however mixed seeming to be less established for most brain regions. The current meta-analytic review examined (1) the association of the Val66Met SNP and brain volume alterations in schizophrenia by comparing Met allele carriers to Val/Val homozygotes and (2) the association of serum BDNF with brain volume measurements.

METHOD

Studies included in the meta-analyses were identified through an electronic search of PubMed and PsycInfo (via EBSCO) for English language publications from January 2000 through December 2017. Included studies had conducted a genotyping procedure of Val66Met or obtained assays of serum BDNF and obtained brain volume data in patients with psychotic disorders. Nonhuman studies were excluded.

RESULTS

Study 1 which included 52 comparisons of Met carriers and Val/Val homozygotes found evidence of lower right and left hippocampal volumes among Met allele carriers with schizophrenia. Frontal measurements, while also lower among Met carriers, did not achieve statistical significance. Study 2 which included 7 examinations of the correlation between serum BDNF and brain volume found significant associations between serum BDNF levels and right and left hippocampal volume with lower BDNF corresponding to lower volumes.

DISCUSSION

The meta-analyses provided evidence of associations between brain volume alterations in schizophrenia and variations on the Val66Met SNP and serum BDNF. Given the limited number of studies, it remains unclear if BDNF effects are global or regionally specific.

Evaluation on Long-Term Test-Retest Reliability of the Short-Form Childhood Trauma Questionnaire in Patients with Schizophrenia

Background

Many studies have reported an association between childhood trauma exposure and schizophrenia. Among these studies, the Short-form Childhood Trauma Questionnaire (CTQ-SF) is one of the most widely used measures of childhood trauma. However, little is known regarding the long-term reliability of the CTQ-SF, especially in patients with psychopathology.

Methods

The CTQ-SF was administered to 50 patients diagnosed with schizophrenia from a hospital in Changsha, Hunan, China. These patients were asked to re-complete the CTQ-SF when they were re-hospitalized or received outpatient treatments in the same hospital within 4 years of follow-up. Intraclass correlation coefficient (ICC) was used to assess test–retest reliability of the CTQ-SF over the intervals. Associations of the CTQ-SF with the Positive and Negative Syndrome Scale (PANSS) and Wechsler Adult Intelligence Scale (WAIS) were tested using Spearman correlation coefficients.

Results

Among the participants, 35 (70.0%) patients re-completed the CTQ-SF after an interval averaging 11.26 months. Excellent test–retest reliabilities (with ICC > 0.75) were found for the total CTQ-SF score (ICC = 0.772) as well as scores of the emotional abuse (ICC = 0.808), physical abuse (ICC = 0.756), sexual abuse (ICC = 0.877) and physical neglect (ICC = 0.751) subscales. Meanwhile, a moderate test–retest reliability was found for the emotional neglect subscale (ICC = 0.538). At both baseline and follow-up, no significant correlations (p > 0.05) were found between CTQ-SF scores and any other clinical assessments.

Conclusion

Our results suggest that CTQ-SF is reliable to assess childhood trauma exposures in schizophrenia over relatively long intervals, regardless of patients’ current symptoms and states of cognition.

Inflammatory biomarkers and cognitive functioning in individuals with euthymic bipolar disorder: exploratory study

BACKGROUND

Neurobiological research frequently implicates inflammatory and neurogenic components with core aspects of bipolar disorder. Even in periods of symptom remission (euthymia), individuals with bipolar disorder experience cognitive impairments, which are increasingly being proposed as an outcome for interventions; identifying biomarkers associated with cognitive impairment in people with bipolar disorder could advance progress in this therapeutic field through identifying biological treatment targets.

AIMS

We aimed to identify proteomic biomarker correlates of cognitive impairment in individuals with euthymic bipolar disorder.

METHOD

Forty-four adults with a bipolar disorder diagnosis in euthymia underwent a battery of cognitive assessments and provided blood for biomarkers. We examined a comprehensive panel of inflammatory and trophic proteins as putative cross-sectional predictors of cognition, conceptualised according to recommended definitions of clinically significant cognitive impairment (binary construct) and global cognitive performance (continuous measure).

RESULTS

A total of 48% of the sample met the criteria for cognitive impairment. Adjusting for potentially important covariates, regression analyses identified lower levels of three proteins as significantly and independently associated with cognitive deficits, according to both binary and continuous definitions (interleukin-7, vascular endothelial growth factor C and placental growth factor), and one positively correlated with (continuous) global cognitive performance (basic fibroblast growth factor).

CONCLUSIONS

This study identifies four candidate markers of cognitive impairment in bipolar disorder, none of which have been previously compared with cognitive function in participants with bipolar disorder. Pending replication in larger samples and support from longitudinal studies, these markers could have implications for treating cognitive dysfunction in this patient population.

Systemic inflammation and grey matter volume in schizophrenia and bipolar disorder: Moderation by childhood trauma severity

BACKGROUND

Elevated levels of systemic inflammation are consistently reported in both schizophrenia (SZ) and bipolar-I disorder (BD), and are associated with childhood trauma exposure. We tested whether childhood trauma exposure moderates associations between systemic inflammation and brain morphology in people with these diagnoses.

METHODS

Participants were 55 SZ cases, 52 BD cases and 59 healthy controls (HC) who underwent magnetic resonance imaging. Systemic inflammation was measured using a composite z-score derived from serum concentrations of interleukin 6, tumor necrosis factor alpha and C-reactive protein. Indices of grey matter volume covariation (GMC) were derived from independent component analysis. Childhood trauma was measured using the Childhood Trauma Questionnaire (CTQ Total score).

RESULTS

A series of moderated moderation analyses indicated that increased systemic inflammation were associated with increased GMC in the striatum and cerebellum among all participants. Severity of childhood trauma exposure moderated the relationship between systemic inflammation and GMC in one component, differently among the groups. Specifically, decreased GMC in the PCC/precuneus, parietal lobule and postcentral gyrus, and increased GMC in the left middle temporal gyrus was associated with increased systemic inflammation in HC individuals exposed to high (but not low or average) levels of trauma and in SZ cases exposed to low (but not average or high) levels of trauma, but not in BD cases.

CONCLUSIONS

Increased systemic inflammation is associated with grey matter changes in people with psychosis, and these relationships may be partially and differentially moderated by childhood trauma exposure according to diagnosis.

Exploring the Interplay Between Adversity, Neurocognition, Social Cognition, and Functional Outcome in People With Psychosis: A Narrative Review

History of adversity is associated with subsequent psychosis, and with a spectrum of cognitive alterations in individuals with psychosis. These cognitive features go from neurocognitive aspects as working memory and attention, to complex social cognitive processes as theory of mind and emotional perception. Difficulties in these domains impact patients' social and occupational functioning, which has been shown to be more impaired in those previously exposed to childhood trauma. However, the interplay between adversity, neurocognition, and functioning is yet poorly understood. This narrative review aims to explore the evidence on whether deficits in neurocognitive and social cognitive domains may act as possible putative mechanism linking adversity with functioning in people with psychosis. We show available evidence supporting the link between adversity and poorer functioning in psychosis, especially in chronic stages; and replicated evidence suggesting associations of social cognition and, to a lesser extent, neurocognition with impairment in functioning in patients; although there is still an important gap in the literature testing particularly deficits in social cognition as mediator of the link between adversity and functional decline in psychosis. Targeting interventions focusing on neurocognition and social cognition in individuals with adversity and psychosis seems important, given the severe deterioration of these patients in these domains, although more research is needed to test whether such treatments can specifically improve functioning in individuals with psychosis and adversity. Literature aiming to understand the determinants of functional outcome should consider the pervasive impact of childhood adversity, and its related effects on cognition.

Childhood Maltreatment in Bipolar Disorders

In this chapter, we will focus on childhood maltreatment and its role in the vulnerability to BD.We will review how childhood maltreatment and trauma not only predispose to the development of BD but also to a more unstable, pernicious, and severe clinical expression of the disorder. This environmental risk factor is suggested to be part of a multiple hit model of vulnerability, involving not only early stressors (prenatal and postnatal ones) but also interactions with the genetic background of individuals and with other stressors occurring later in life. We will also review how childhood maltreatment and trauma may modify the brain functioning and circuits and alter some biological pathways in BD, hence leading to psychopathology. Finally, we will briefly discuss the implications for clinical practice and treatment.

The Impact of Childhood Trauma on Developing Bipolar Disorder: Current Understanding and Ensuring Continued Progress

Childhood trauma (CT) has been repeatedly linked to earlier onset and greater severity of bipolar disorder (BD) in adulthood. However, such knowledge is mostly based on retrospective and cross-sectional studies in adults with BD. The first objective of this selective review is to characterize the short-term effects of CT in the development of BD by focusing on studies in young people. The second objective is to describe the longer-term consequences of CT by considering studies with adult participants. This review first outlines the most prominent hypotheses linking CT exposure and the onset of BD. Then, it summarizes the psychological and biological risk factors implicated in the development of BD, followed by a discussion of original studies that investigated the role of CT in young people with early-onset BD, youths at increased risk of developing BD, or young people with BD with a focus on subclinical and clinical outcome measures. The review considers additional biological and psychological factors associated with a negative impact of CT on the long-term course of BD in later adulthood. Finally, we discuss how the integration of information of CT can improve ongoing early identification of BD and mitigate severe clinical expression in later adulthood.

Considering the Microbiome in Stress-Related and Neurodevelopmental Trajectories to Schizophrenia

Early life adversity and prenatal stress are consistently associated with an increased risk for schizophrenia, although the exact pathogenic mechanisms linking the exposures with the disease remain elusive. Our previous view of the HPA stress axis as an elegant but simple negative feedback loop, orchestrating adaptation to stressors among the hypothalamus, pituitary, and adrenal glands, needs to be updated. Research in the last two decades shows that important bidirectional signaling between the HPA axis and intestinal mucosa modulates brain function and neurochemistry, including effects on glucocorticoid hormones and brain-derived neurotrophic factor (BDNF). The intestinal microbiome in earliest life, which is seeded by the vaginal microbiome during delivery, programs the development of the HPA axis in a critical developmental window, determining stress sensitivity and HPA function as well as immune system development. The crosstalk between the HPA and the Microbiome Gut Brain Axis (MGBA) is particularly high in the hippocampus, the most consistently disrupted neural region in persons with schizophrenia. Animal models suggest that the MGBA remains influential on behavior and physiology across developmental stages, including the perinatal window, early childhood, adolescence, and young adulthood. Understanding the role of the microbiome on critical risk related stressors may enhance or transform of understanding of the origins of schizophrenia and offer new approaches to increase resilience against stress effects for preventing and treating schizophrenia.

The impact of BDNF Val66Met on cognitive skills in veterans with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a trauma-induced disorder characterized with impaired cognitive function. BDNF modulates cognition and is involved in neuroprotection and neurocognitive processing. The BDNF Val66Met polymorphism was found to influence cognitive functions. In PTSD, carriers of the BDNF GG genotype had better spatial processing of navigation performance, and lower hyperarousal and startle reaction than A allele carriers. The hypothesis was that veterans with PTSD, carriers of the BDNF Val66Met A allele, will show reduced cognitive skills. The study included 315 male Caucasian combat veterans, with (N = 199) or without (N = 116) current and chronic PTSD. Cognition was assessed using the Rey-Osterrieth Complex Figure (ROCF) test that determines visual-spatial perception and short and long-term visual memory function. The results revealed that cognitive decline measured with ROCF test was associated with PTSD. Presence of the BDNF Val66Met GG genotype in veterans with PTSD, but not in veterans without PTSD, showed protective association with visual short-term memory and visual object manipulation after few seconds (executive function), assessed with the ROCF immediate recall test, compared to the A carriers with PTSD. In conclusion, this was the first study to confirm the association between BDNF Val66Met and memory and attention performed with ROCF in male veterans with PTSD. The results corroborated that the BDNF Val66Met A allele, compared to GG genotype, is associated with poorer short-term visual memory and attention linked with executive functions, in veterans with PTSD.

Brain-derived neurotrophic factor and schizophrenia

The brain-derived neurotrophic factor (BDNF) is a secretory growth factor that promotes neuronal proliferation and survival, synaptic plasticity and long-term potentiation in the central nervous system. Brain-derived neurotrophic factor biosynthesis and secretion are chrono-topically regulated processes at the cellular level, accounting for specific localizations and functions. Given its role in regulating brain development and activity, BDNF represents a potentially relevant gene for schizophrenia, and indeed BDNF and its non-synonymous functional variant, rs6265 (C → T, Val → Met) have been widely studied in psychiatric genetics. Human and animal studies have indicated that brain-derived neurotrophic factor is relevant for schizophrenia-related phenotypes, and that: (1) fine-tuned regulation of brain-derived neurotrophic factor secretion and activity is necessary to guarantee brain optimal development and functioning; (2) the Val → Met substitution is associated with impaired activity-dependent secretion of brain-derived neurotrophic factor; (3) disruption of brain-derived neurotrophic factor signaling is associated with altered synaptic plasticity and neurodevelopment. However, genome-wide association studies failed to associate the BDNF locus with schizophrenia, even though a sub-threshold association exists. Here, we will review studies focused on the relationship between the genetic variation of BDNF and schizophrenia, trying to fill the gap between genetic risk per se and insights from molecular biology. A deeper understanding of brain-derived neurotrophic factor biology and of the epigenetic regulation of brain-derived neurotrophic factor and its interactome during development may help clarifying the potential role of this gene in schizophrenia, thus informing development of brain-derived neurotrophic factor-based strategies of prevention and treatment of this disorder.

Childhood Trauma in Persons With Schizophrenia and a History of Interpersonal Violence

BACKGROUND

Childhood trauma is a risk factor for psychosis as well for violent behavior and offending later in life. Childhood trauma comprises subdomains of abuse and neglect that may be differently related to later violence among patients with schizophrenia. The aim of this study was to map the subdomains of childhood trauma associated with violent offending in schizophrenia.

METHODS

Information on childhood trauma from predominantly male patients with a DSM-IV diagnosis of schizophrenia and a history of violent offending (interpersonal violence) (SCZ-V, n = 19), schizophrenia patients without a history of violence (SCZ-NV, n = 34), and healthy controls (HC, n = 66) was obtained with the Childhood Trauma Questionnaire (CTQ). Differences between groups in total maltreatment scores and the five subdomains including physical, emotional, and sexual abuse, as well as physical and emotional neglect were analyzed.

RESULTS

SCZ-V had the highest median CTQ scores for all sub-domains. SCZ-V reported significantly higher total CTQ scores than SCZ-NV and HC. SCZ-V had significantly higher scores than HC on all subdomains, and significantly higher than SCZ-NV on physical and emotional neglect. SCZ-NV had higher scores on all domains except sexual abuse compared to HC.

CONCLUSION

SCZ-V patients had higher exposure to childhood trauma than SCZ-NV, and both schizophrenia groups had higher exposure than HC. The results suggest that childhood physical and emotional neglect may be of specific importance to later violence in schizophrenia.

Childhood Trauma and Psychosis: An Updated Review

There is growing evidence to support the link between childhood trauma and psychosis. Childhood trauma increases the risk for psychosis and affects severity and type of psychotic symptoms, and frequency of comorbid conditions, including depression and substance use. Childhood trauma is linked to more severe functional impairment in individuals with psychosis. There is evidence to support gender differences in the influence of childhood trauma on the course of psychotic illnesses, appearing to be more profound in girls and women. Other biological markers that may explain the link between childhood trauma and psychosis include brain-derived neurotrophic factor and other inflammatory markers.

Effects of BDNF Signaling on Anxiety-Related Behavior and Spatial Memory of Adolescent Rats in Different Length of Maternal Separation

As an adverse form of early-life stress (ELS), maternal separation (MS) can interfere with the development of cognition and behaviors of adolescent rodents. Brain-derived neurotrophic factor (BDNF) is involved in the regulation of brain development and function, but the molecular mechanisms by which BDNF regulates brain function and behavior in MS with different stressor strengths remain unclear. This descriptive study characterized the levels of BDNF in the prefrontal cortex (PFC) and plasma corticosterone (CORT) from the offspring of rats exposed to early handling (EH, 15-min separation per day) and prolonged MS (PMS, 180-min separation per day), during postnatal days (PND) 1‑21. The behavioral and biochemical analyses were performed during adolescence (PND 42‑56). PMS resulted in reduced weight and decreased locomotor activity in the open field test and Y-maze task compared to control (CON) group, with EH showing an intermediate phenotype. BDNF protein levels in the PFC were lower in PMS compared to EH and further reduced in CON male rats. Plasma CORT levels were higher in PMS compared to CON with EH again showing intermediate levels. Neither PMS or EH affected spatial learning in the Y-maze task. These findings indicate that longer periods of maternal separation are necessary to increase anxiety-like behavior, elevate CORT levels, and further suppress BDNF levels in the PFC, providing a possible mechanism to explain why more severe forms of ELS lead to more significant psychiatric and medical consequences later in life.

Childhood Trauma and Neurocognition in Adults With Psychotic Disorders: A Systematic Review and Meta-analysis

BACKGROUND

Characterizing the link between childhood trauma and adult neurocognitive function in psychosis is crucial for improving the fields understanding of how early environmental risk factors impact the presentation of the disorder. To date, the literature has been inconsistent: meta-analytic synthesis is lacking, and it is unclear whether specific cognitive functions are affected.

METHODS

A meta-analysis was performed on a total of 3315 subjects with a psychotic disorder. The links between childhood trauma, overall neurocognitive function, and four cognitive subdomains (working memory, executive function, verbal/visual memory, and attention/processing speed) were examined. Relevant sample characteristics and methodological moderators were tested. The strength of the association between trauma and overall neurocognition in individuals with psychotic disorders was also compared to that of healthy controls.

RESULTS

Among individuals with psychotic disorders, there was a significant association between overall cognition and childhood trauma, r = -.055; 95% CI = -0.09, -0.02, P = .002. There was also a modest, negative relationship between childhood trauma and working memory, r = -.091; 95% CI = -0.15, -0.03, P = .002. Moderators did not have a significant effect on these analyses. Further, the association between childhood trauma and neurocognition was significantly stronger in healthy controls compared to patients with a psychotic disorder.

CONCLUSION

A small negative association was found between overall cognition and childhood trauma in individuals with psychotic disorders. Results suggest the association is less strong for individuals with a psychotic disorder compared to healthy populations. Findings are informative for prominent etiological models of psychosis.

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.

Childhood Trauma in Schizophrenia: Current Findings and Research Perspectives

Schizophrenia is a severe neuropsychiatric disorder with persistence of symptoms throughout adult life in most of the affected patients. This unfavorable course is associated with multiple episodes and residual symptoms, mainly negative symptoms and cognitive deficits. The neural diathesis-stress model proposes that psychosocial stress acts on a pre-existing vulnerability and thus triggers the symptoms of schizophrenia. Childhood trauma is a severe form of stress that renders individuals more vulnerable to developing schizophrenia; neurobiological effects of such trauma on the endocrine system and epigenetic mechanisms are discussed. Childhood trauma is associated with impaired working memory, executive function, verbal learning, and attention in schizophrenia patients, including those at ultra-high risk to develop psychosis. In these patients, higher levels of childhood trauma were correlated with higher levels of attenuated positive symptoms, general symptoms, and depressive symptoms; lower levels of global functioning; and poorer cognitive performance in visual episodic memory end executive functions. In this review, we discuss effects of specific gene variants that interact with childhood trauma in patients with schizophrenia and describe new findings on the brain structural and functional level. Additive effects between childhood trauma and brain-derived neurotrophic factor methionine carriers on volume loss of the hippocampal subregions cornu ammonis (CA)4/dentate gyrus and CA2/3 have been reported in schizophrenia patients. A functional magnetic resonance imaging study showed that childhood trauma exposure resulted in aberrant function of parietal areas involved in working memory and of visual cortical areas involved in attention. In a theory of mind task reflecting social cognition, childhood trauma was associated with activation of the posterior cingulate gyrus, precuneus, and dorsomedial prefrontal cortex in patients with schizophrenia. In addition, decreased connectivity was shown between the posterior cingulate/precuneus region and the amygdala in patients with high levels of physical neglect and sexual abuse during childhood, suggesting that disturbances in specific brain networks underlie cognitive abilities. Finally, we discuss some of the questionnaires that are commonly used to assess childhood trauma and outline possibilities to use recent biostatistical methods, such as machine learning, to analyze the resulting datasets.

Hippocampus, Amygdala, and Thalamus Volumes in Very Preterm Children at 8 Years: Neonatal Pain and Genetic Variation

Altered hippocampal morphology and reduced volumes have been found in children born preterm compared to full-term. Stress inhibits neurogenesis in the hippocampus, and neonatal stress/noxious stimulation in rodent pups are associated with long-term alterations in hippocampal volumes. We have previously shown reduced cortical thickness and cerebellar volumes in relation to more exposure to pain-related stress of neonatal invasive procedures in children born very preterm. We have reported targeted gene-by-pain environment interactions that contribute to long-term brain development and outcomes in this population. We now aim to determine whether exposure to pain-related stress (adjusted for clinical factors and genotype) differentially impacts regional structures within the limbic system and thalamus, and investigate relationships with outcomes in very preterm children. Our study included 57 children born very preterm (<32 weeks GA) followed longitudinally from birth who underwent 3-D T1 MRI neuroimaging at ∼8 years. Hippocampal subfields and white matter tracts, thalamus and amygdala were automatically segmented using the MAGeT Brain algorithm. The relationship between those subcortical brain volumes (adjusted for total brain volume) and neonatal invasive procedures, gestational age (GA), illness severity, postnatal infection, days of mechanical ventilation, number of surgeries, morphine exposure, and genotype (COMT, SLC6A4, and BDNF) was examined using constrained principal component analysis. We found that neonatal clinical factors and genotypes accounted for 46% of the overall variance in volumes of hippocampal subregions, tracts, basal ganglia, thalamus and amygdala. After controlling for clinical risk factors and total brain volume, greater neonatal invasive procedures was associated with lower volumes in the amygdala and thalamus (p = 0.0001) and an interaction with COMT genotype predicted smaller hippocampal subregional volume (p = 0.0001). More surgeries, days of ventilation, and lower GA were also related to smaller volumes in various subcortical regions (p < 0.002). These reduced volumes were in turn differentially related to poorer cognitive, visual-motor and behavioral outcomes. Our findings highlight the complexity that interplays when examining how exposure to early-life stress may impact brain development both at the structural and functional level, and provide new insight on possible novel avenues of research to discover brain-protective treatments to improve the care of children born preterm.

Effects of BDNF Val66Met genotype and schizophrenia familial risk on a neural functional network for cognitive control in humans

Cognitive control represents an essential neuropsychological characteristic that allows for the rapid adaption of a changing environment by constant re-allocation of cognitive resources. This finely tuned mechanism is impaired in psychiatric disorders such as schizophrenia and contributes to cognitive deficits. Neuroimaging has highlighted the contribution of the anterior cingulate cortex (ACC) and prefrontal regions (PFC) on cognitive control and demonstrated the impact of genetic variation, as well as genetic liability for schizophrenia. In this study, we aimed to examine the influence of the functional single-nucleotide polymorphism (SNP) rs6265 of a plasticity-related neurotrophic factor gene, BDNF (Val⁶⁶Met), on cognitive control. Strong evidence implicates BDNF Val⁶⁶Met in neural plasticity in humans. Furthermore, several studies suggest that although the variant is not convincingly associated with schizophrenia risk, it seems to be a modifier of the clinical presentation and course of the disease. In order to clarify the underlying mechanisms using functional magnetic resonance imaging (fMRI), we studied the effects of this SNP on ACC and PFC activation, and the connectivity between these regions in a discovery sample of 85 healthy individuals and sought to replicate this effect in an independent sample of 253 individuals. Additionally, we tested the identified imaging phenotype in relation to schizophrenia familial risk in a sample of 58 unaffected first-degree relatives of schizophrenia patients. We found a significant increase in interregional connectivity between ACC and PFC in the risk-associated BDNF ⁶⁶Met allele carriers. Furthermore, we replicated this effect in an independent sample and demonstrated its independence of structural confounds, as well as task specificity. A similar coupling increase was detectable in individuals with increased familial risk for schizophrenia. Our results show that a key neural circuit for cognitive control is influenced by a plasticity-related genetic variant, which may render this circuit particular susceptible to genetic and environmental risk factors for schizophrenia.

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.

The impact of BDNF Val66Met polymorphism on cognition in Bipolar Disorder: A review: Special Section on "Translational and Neuroscience Studies in Affective Disorders" Section Editor, Maria Nobile MD, PhD. This Section of JAD focuses on the relevance of translational and neuroscience studies in providing a better understanding of the neural basis of affective disorders. The main aim is to briefly summaries relevant research findings in clinical neuroscience with particular regards to specific innovative topics in mood and anxiety disorders

BACKGROUND

Converging lines of evidence suggest that Brain-Derived Neurotrophic Factor (BDNF) may play a central role in the pathogenesis of Bipolar Disorder (BD), thus representing a valid biomarker of the disease. A common genetic variation in the BDNF gene, the Val66Met, is associated with reduced maturation and secretion of BDNF and therefore it has been related to specific mood, cognitive and neuroanatomical alterations in BD. However, so far, only a handful of studies have investigated the association between Val66Met polymorphism and cognitive functioning in BD.

METHODS

We performed a bibliographic search on PUBMED of all genetic studies investigating Val66Met modulation on cognitive performances in BD subjects. The inclusion criteria were met by nine studies, including a total amount of 897 BD subjects and 803 healthy controls.

RESULTS

From the analysis of the existing literature emerged that a) Val allele in BD adults, but not in BD adolescents, was associated with better performances in selective cognitive domains including executive functions, verbal learning and memory; b) Met allele may negatively modulate the association between childhood trauma and performances in memory, verbal ability and verbal fluency tasks; c) Met allele may also negatively regulate structural abnormalities in cognitive cerebral structures; d) Val/Met carriers showed greater improvements in cognitive functions compared to Val/Val and Met/Met carriers.

LIMITATIONS

Few genetic studies exploring the impact of Val66Met on cognition in BD.

CONCLUSIONS

Val66Met polymorphism likely modulates cognitive functions in BD patients with complex gene-environment interactions and through potential modulations of cerebral structures. Further and larger genetic studies are required in order to detect association between BDNF polymorphism, BDNF levels, brain abnormalities and cognition in BD.

Traumatic experiences and cognitive profiles of schizophrenia cases influenced by the BDNF Val66met polymorphism

The association of early trauma exposure with current cognition was examined in a research series of 56 schizophrenia cases with respect to the BDNF Val66Met polymorphism (rs6265, Val66Val, Val66Met, Met66Met), as met allele carriers have reduced neurotrophic activity. The Perceptual Organization Index had a significant negative correlation with trauma exposures only in met carriers, including early physical abuse, general trauma after age 18 years, and physical abuse. Within the Val66Val subgroup, there were no significant correlations between WAIS indices and traumatic experiences.

Imaging Genetics Towards a Refined Diagnosis of Schizophrenia

Current diagnoses of schizophrenia and related psychiatric disorders are classified by phenomenological principles and clinical descriptions while ruling out other symptoms and conditions. Specific biomarkers are needed to assist the current diagnostic system. However, complicated gene and environment interactions induce great disease heterogeneity. This unclear etiology and heterogeneity raise difficulties in distinguishing schizophrenia-related effects. Simultaneously, the overlap in symptoms, genetic variations, and brain alterations in schizophrenia and related psychiatric disorders raises similar difficulties in determining disease-specific effects. Imaging genetics is a unique methodology to assess the impact of genetic factors on both brain structure and function. More importantly, imaging genetics builds a bridge to understand the behavioral and clinical implications of genetics and neuroimaging. By characterizing and quantifying the brain measures affected in psychiatric disorders, imaging genetics is contributing to identifying potential biomarkers for schizophrenia and related disorders. To date, candidate gene analysis, genome-wide association studies, polygenetic risk score analysis, and large-scale collaborative studies have made contributions to the understanding of schizophrenia with the potential to serve as biomarkers. Despite limitations, imaging genetics remains promising as more aggregative, clustering methods and imaging genetics-compatible clinical assessments are employed in future studies. We review imaging genetics' contribution to our understanding of the heterogeneity within schizophrenia and the commonalities across schizophrenia and other diagnostic borders, and we will discuss whether imaging genetics is ready to form its own diagnostic system.

The role of childhood trauma in cognitive performance in schizophrenia and bipolar disorder - A systematic review

Childhood trauma (CT) has repeatedly been associated with cognitive deficits in patients with psychosis but many inconsistencies have been reported so that the nature of the relationship remains unclear. The purpose of this review was to better characterize the contribution of CT to cognitive deficits by considering the type, severity and frequency of childhood traumatic events and their relationships with psychosis at all stages.

Relevant studies were identified via electronic and manual literature searches and included original studies that investigated the relationship between CT and higher cognitive performance or social cognitive performance in patients with schizophrenia, bipolar disorder and psychosis at all stages of the illness stages (i.e. ultra-high risk, first episode or chronic phase).

Overall, a majority of studies reported that patients who experienced CT displayed deficits in general cognitive ability compared to patients with psychosis without such a history. Associations between CT and other cognitive function were more mixed. When comparing patient groups, the association between CT and cognitive function was more inconsistent in patients with chronic schizophrenia than in healthy participants, ultra-high risk individuals, first-episode patients and patients with chronic bipolar disorder.

In understanding the variability in the reported relationships between CT and cognition across study populations, we highlight the variety of questionnaires used and discuss the likelihood of there being differences in cognitive function based on specific stressors, severity and frequency. Finally, we consider future research steps that may shed light on psychobiological mechanisms underlying CT and cognitive performance in patients with psychosis.

Impact of brain-derived neurotrophic factor genetic polymorphism on cognition: A systematic review

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) has an important role in the neurogenesis and neuroplasticity of the brain. This systematic review was designed to examine the association between BDNF Val66Met (rs6265) polymorphism and four cognitive domains-attention and concentration, executive function, verbal fluency, and memory, respectively.

METHODOLOGY

Primary literature search was performed using search engines such as PubMed and Scopus. Observational studies that evaluated the neurocognitive performances in relation to BDNF polymorphism within human subjects were included in this review, while animal studies, overlapping studies, and meta-analysis were excluded.

RESULTS

Forty of 82 reviewed studies (48.8%) reported an association between Val66Met polymorphism and neurocognitive domains. The proportion of the studies showing positive findings in cognitive performances between Val/Val homozygotes and Met carriers was comparable, at 30.5% and 18.3%, respectively. The highest percentage of positive association between Val66Met polymorphism and neurocognition was reported under the memory domain, with 26 of 63 studies (41.3%), followed by 18 of 47 studies (38.3%) under the executive function domain and four of 23 studies (17.4%) under the attention and concentration domain. There were no studies showing an association between Val66Met polymorphism and verbal fluency. In particular, Val/Val homozygotes performed better in tasks related to the memory domain, while Met carriers performed better in terms of executive function, in both healthy individuals and clinical populations.

CONCLUSION

While numerous studies report an association between Val66Met polymorphism and neurocognitive changes in executive function and memory domains, the effect of Met allele has not been clearly established.

Early life experiences and social cognition in major psychiatric disorders: A systematic review

Objective:

To present a systematic review of the literature on the associations between early social environment, early life adversity, and social cognition in major psychiatric disorders, including schizophrenia, bipolar disorder, borderline personality disorder, major depressive disorder and posttraumatic stress disorder.

Method:

Relevant studies were identified via electronic and manual searches of the literature and included articles written in English and published in peer-reviewed journals up to May 2018. Quality assessment was performed using the quality evaluation scale employed in previous systematic reviews.

Results:

A total of 25 studies were included in the systematic review with the quality assessment scores ranging from 3 to 6 (out of 6). The vast majority of the studies reviewed showed a significant association between early childhood social experience, including both insecure attachment and adversity relating to neglect or abuse, and poorer social cognitive performance.

Conclusion:

We discuss these findings in the context of an attachment model, suggesting that childhood social adversity may result in poor internal working models, selective attention toward emotional stimuli and greater difficulties with emotional self-regulation. We outline some of the steps required to translate this understanding of social cognitive dysfunction in major psychiatric disorders into a target for interventions that mitigate the adverse effects of childhood maltreatment and poor parental attachment on social cognition.

Impact of childhood trauma on sensorimotor gating in Chinese patients with chronic schizophrenia

We investigated the relationship between childhood trauma (CT) and sensorimotor gating in Chinese patients diagnosed with chronic schizophrenia. Seventy-five patients were assessed with the Childhood Trauma Questionnaire-Short Form (CTQ-SF), and then the modified paradigm, perceived spatial separation-induced prepulse inhibition (PSS PPI) and the perceived spatial co-location PPI (PSC PPI or classical PPI) were applied to test sensorimotor gating. Startling stimuli (90 dB) were presented either alone or preceded by discrete prepulse stimuli of 4 dB in a background 60-dB noise level. Associations between CT and various PPI paradigms were statistically analyzed. Univariate analysis revealed the absence of a significant correlation between CT and PPI paradigms (p > 0.05). However, multiple linear regression analyses revealed that sexual abuse and the positive and negative syndrome scale (PANSS) score were negatively correlated with PSS PPI (p = 0.029 and 0.008, respectively). On the other hand, female sex and history of smoking were positively correlated with PSS PPI (p = 0.044 and 0.043, respectively). In conclusion, the results of this study suggest that CT can be a predisposing factor that affects sensorimotor gating in schizophrenia patients.

Targeting recovery in first episode psychosis: The importance of neurocognition and premorbid adjustment in a 3-year longitudinal study

INTRODUCTION

Recovery in psychotic disorders remains a major challenge across mental health. Identifying predictors of recovery in first psychotic episodes is a priority in order to increase knowledge on underlying mechanisms of the illness and to obtain objective severity markers at initial phases. In this study we gathered sociodemographic, clinical and cognitive data to explore predictive variables of recovery after three years follow-up in a sample of 399 patients with a first episode of psychosis (FEP).

MATERIAL AND METHOD

This is a longitudinal study including patients with a FEP. A dichotomic variable of recovery was created according to symptomatic and functional outcome after 3years follow-up. Significant variables in univariate analysis were entered into a binary logistic regression to obtain a multivariate prediction model of recovery.

RESULTS

The predictive model was statistically significant and classified an overall of 76% of patients correctly, specifically 86.7% of patients that would not recover and 55% of the patients that would recover. From all the variables that where significantly different between recovered and not recovered patients, only speed of processing, executive functions and premorbid adjustment were found to be significant predictors of recovery.

DISCUSSION

This study provides evidence that the degree of basal impairment in cognitive functions related to the Prefrontal Cortex and a worst premorbid adaptation predict in a significant way which patients are less likely to recover three years after a FEP.

Childhood trauma interacted with BDNF Val66Met influence schizophrenic symptoms

The gene - environment (G × E) interaction effect is involved in severe mental disorders. However, whether the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism participates in the childhood-abuse influenced schizophrenic symptoms remains unclear. We examined the interaction between BDNF Val66Met, and childhood trauma (ChT) on psychotic symptoms in a Chinese Han population.To estimate the G × E interaction, psychiatric interviews, self-report questionnaires for ChT, and genotyping for BDNF Val66Met were carried out on 201 schizophrenic patients. G × E interactions were analyzed by generalized multifactor dimensionality reduction (GMDR).Among all patients, 11.9%, 19.4%, 23.4%, 26.4%, and 73.6% reported emotional abuses, physical abuses (PA), sexual abuses (SA), emotional neglects (EN), and physical neglects (PN), respectively. Significant negative correlations were observed between anxiety/depression factors, and ChT total scores. Patients with 3 different BDNF genotypes showed significant differences in anxiety/depression scores. Significant 2-way interactions were found for Val66Met × PN, 3-way interactions were found for Val66Met × PN × PA, and four-way interactions were found for Val66Met × PN × PA × EN with regard to the excitement scores.Our findings suggested an involvement of BDNF Val66Met polymorphism after ChT in terms of risk for schizophrenia symptoms.

Interaction between BDNF and TNF-α genes in schizophrenia

OBJECTIVE

Our recent work reported that tumor necrosis factor-α (TNF-α) is negatively correlated with brain-derived neurotrophic factor (BDNF) in patients with schizophrenia. A previous study has shown that TNF-α could regulate the extracellular secretion of BDNF. Therefore, we hypothesized that the TNF-α gene (TNF-α) may interact with the BDNF gene (BDNF) to influence schizophrenia risk.

METHODS

We recruited 694 patients with schizophrenia from three mental hospitals in Eastern China and 725 healthy controls. The Positive and Negative Syndrome Scale (PANSS) was employed to evaluate symptom severity. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was performed to assess cognitive function. The SNPs rs6265 in BDNF and rs1799964 in TNF-α were genotyped.

RESULTS

There were no significant differences in allele and genotype frequencies in either rs6265 or rs1799964 between the case and control groups. A significant association of rs6265 AA + AG × rs1799964 CC + CT with schizophrenia was observed (OR = 1.14, 95%CI: 1.02-1.27; P = .02). There were significant differences in the RBANS attention and total scores between the patients with rs6265A and rs1799964C alleles and those without these two alleles (P = .03 and P = .03 after Bonferroni correction, respectively).

CONCLUSION

Our findings provided preliminary evidence that the interaction of BDNF and TNF-α may confer susceptibility to schizophrenia and cognitive dysfunction.

Defining the impact of childhood adversities on cognitive deficits in psychosis: An exploratory analysis

BACKGROUND

Exposure to adverse childhood experiences (ACE) and cognitive deficits are both prevalent in psychosis. While it has been repeatedly demonstrated that ACE contribute to cognitive dysfunctions, the specific nature of this contribution remains elusive. Recent evidence suggests that types of adversities during critical periods have deleterious effects on brain structures that are important for cognitive functioning. The present study sought to clarify which types of adversities experienced at which time during development aggravate cognitive deficits in psychosis.

METHODS

Exposure to abuse and neglect during childhood and adolescence were retrospectively assessed in N=168 adult individuals with psychotic disorder. Conditioned random forest regression was used to define the importance of type and timing of ACE for predicting domains of the MATRICS Consensus Cognitive Battery (MCCB).

RESULTS

Significant importance of ACE was determined for 5 out of 7 MCCB domains. Particularly abuse at age 3 contributed to dysfunctional cognitive domains attention, learning, and working memory. Social cognition was related to neglect experienced at 11-12years, and to cumulative ACE.

CONCLUSION

Abuse and neglect at periods when children spend substantial time in their families affect cognitive functioning, and hence aggravate dysfunction in psychosis. Results support the neurodevelopmental perspective on psychosis and the diagnostic value of type and timing of ACE.

Traumatic Life Events in Relation to Cognitive Flexibility: Moderating Role of the BDNF Val66Met Gene Polymorphism

Cognitive flexibility plays an important role in an individual's ability to adapt to a continuously changing environment and is considered central to goal-oriented behavior. Accordingly, increasing attention has been devoted to understanding the factors, including genetic and early life experiences, which might contribute to individual differences in this ability. In the present investigation, we examined the contribution of the BDNF Val66Met polymorphism to cognitive flexibility, as assessed by set-shifting ability on the Wisconsin Card Sorting Task (WCST), and whether this polymorphism moderated the relation between trauma experiences (including type and timing of trauma occurrence) and cognitive flexibility. Among undergraduate students (N = 239), greater frequency of total traumas experienced prior to the age 5 was associated with greater difficulties in set-shifting (as indexed by more frequent perseverative errors on the WCST) among individuals carrying the Met allele of the BDNF polymorphism, but not those who were Val homozygotes. By contrast, total traumas experienced between the age of 6 to 12 and 13 to 18 were not related to set-shifting ability, and these relations were not moderated by BDNF genotype. Moreover, greater frequency of general traumas and emotional abuse was associated with set-shifting difficulties for both male and female Met allele carriers, but not Val homozygotes. In contrast, physical punishment was related to difficulties in set-shifting, but only among male Met carriers, an effect that was likely attributed to greater frequency of this form of trauma among males. The present findings suggest that the relationship between early life trauma and later-life cognitive flexibility might depend on the presence of the BDNF Val66Met polymorphism as well as the development stage at which the trauma has occurred. Moreover, the present investigation provides further understanding into the factors (i.e., genetic and early life experiences) that might be associated with individual differences in cognitive functioning and goal-directed behaviors, such as problem-solving and decision-making.

The relationship between brain volumes and intelligence in bipolar disorder

OBJECTIVES

Bipolar disorder type-I (BD-I) patients show a lower Intelligence Quotient (IQ) and smaller brain volumes as compared with healthy controls. Considering that in healthy individuals lower IQ is related to smaller total brain volume, it is of interest to investigate whether IQ deficits in BD-I patients are related to smaller brain volumes and to what extent smaller brain volumes can explain differences between premorbid IQ estimates and IQ after a diagnosis of BD-I.

METHODS

Magnetic resonance imaging brain scans, IQ and premorbid IQ scores were obtained from 195 BDI patients and 160 controls. We studied the relationship of (global, cortical and subcortical) brain volumes with IQ and IQ change. Additionally, we investigated the relationship between childhood trauma, lithium- and antipsychotic use and IQ.

RESULTS

Total brain volume and IQ were positively correlated in the entire sample. This correlation did not differ between patients and controls. Although brain volumes mediated the relationship between BD-I and IQ in part, the direct relationship between the diagnosis and IQ remained significant. Childhood trauma and use of lithium and antipsychotic medication did not affect the relationship between brain volumes and IQ. However, current lithium use was related to lower IQ in patients.

CONCLUSIONS

Our data suggest a similar relationship between brain volume and IQ in BD-I patients and controls. Smaller brain volumes only partially explain IQ deficits in patients. Therefore, our findings indicate that in addition to brain volumes and lithium use other disease factors play a role in IQ deficits in BD-I patients.

Neuroimaging genomics in psychiatry-a translational approach

Neuroimaging genomics is a relatively new field focused on integrating genomic and imaging data in order to investigate the mechanisms underlying brain phenotypes and neuropsychiatric disorders. While early work in neuroimaging genomics focused on mapping the associations of candidate gene variants with neuroimaging measures in small cohorts, the lack of reproducible results inspired better-powered and unbiased large-scale approaches. Notably, genome-wide association studies (GWAS) of brain imaging in thousands of individuals around the world have led to a range of promising findings. Extensions of such approaches are now addressing epigenetics, gene–gene epistasis, and gene–environment interactions, not only in brain structure, but also in brain function. Complementary developments in systems biology might facilitate the translation of findings from basic neuroscience and neuroimaging genomics to clinical practice. Here, we review recent approaches in neuroimaging genomics—we highlight the latest discoveries, discuss advantages and limitations of current approaches, and consider directions by which the field can move forward to shed light on brain disorders.

The association between gene variants and longitudinal structural brain changes in psychosis: a systematic review of longitudinal neuroimaging genetics studies

Evidence suggests that genetic variation might influence structural brain alterations in psychotic disorders. Longitudinal genetic neuroimaging (G-NI) studies are designed to assess the association between genetic variants, disease progression and brain changes. There is a paucity of reviews of longitudinal G-NI studies in psychotic disorders. A systematic search of PubMed from inception until November 2016 was conducted to identify longitudinal G-NI studies examining the link between Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI)-based brain measurements and specific gene variants (SNPs, microsatellites, haplotypes) in patients with psychosis. Eleven studies examined seven genes: BDNF, COMT, NRG1, DISC1, CNR1, GAD1, and G72. Eight of these studies reported at least one association between a specific gene variant and longitudinal structural brain changes. Genetic variants associated with longitudinal brain volume or cortical thickness loss included a 4-marker haplotype in G72, a microsatellite and a SNP in NRG1, and individual SNPs in DISC1, CNR1, BDNF, COMT and GAD1. Associations between genotype and progressive brain changes were most frequently observed in frontal regions, with five studies reporting significant interactions. Effect sizes for significant associations were generally of small or intermediate magnitude (Cohen’s d < 0.8). Only two genes (BDNF and NRG1) were assessed in more than one study, with great heterogeneity of the results. Replication studies and studies exploring additional genetic variants identified by large-scale genetic analysis are warranted to further ascertain the role of genetic variants in longitudinal brain changes in psychosis.

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.