Serotonin transporter gene polymorphism, childhood trauma, and cognition in patients with psychotic disorders

Early life adversities, psychopathologies and novel pharmacological strategies

Exposure to adversities during early life stages (early life adversities - ELA), ranging from pregnancy to adolescence, represents a major risk factor for the vulnerability to mental disorders. Hence, it is important to understand the molecular and functional underpinning of such relationship, in order to develop strategies aimed at reducing the psychopathologic burden associated with ELA, which may eventually lead to a significant improvement in clinical practice. In this review, we will initially recapitulate clinical and preclinical evidence supporting the link between ELA and psychopathology and we will primarily discuss the main biological mechanisms that have been described as potential mediators of the effects of ELA on the psychopathologic risk, including the role for genetic factors as well as sex differences. The knowledge emerging from these studies may be instrumental for the development of novel therapeutic strategies aimed not only at correcting the deficits that emerge from ELA exposure, but also in preventing the manifestation of a full-blown psychopathologic condition. With this respect, we will specifically focus on adolescence as a key time frame for disease onset as well as for early therapeutic intervention. We believe that incorporating clinical and preclinical research data in the context of early life adversities can be instrumental to elucidate the mechanisms contributing to the risk for psychopathology or that may promote resilience. This will ultimately allow the identification of 'at risk' individuals who may benefit from specific forms of interventions that, by interfering with disease trajectories, could result in more benign clinical outcomes.

Tobacco smoking related to childhood trauma mediated by cognitive control and impulsiveness in severe mental disorders

BACKGROUND

People with severe mental disorders (SMDs) show an increased prevalence of tobacco smoking compared to the general population. Tobacco smoking and other adult adverse health behaviors have been associated with traumatic experiences in childhood. In the present study we investigated the relationship between childhood trauma and tobacco smoking in people with SMDs, including the possible mediating role of cognitive- and personality characteristics, i.e. cognitive control, impulsiveness, affective lability and self-esteem.

METHODS

Enrolled in the study were 871 participants with schizophrenia (SCZ, N = 484) and bipolar (BD, N = 387) spectrum disorders. We assessed tobacco smoking behavior (yes/no and amount), and history of childhood trauma with the Childhood Trauma Questionnaire. Data on cognitive control, impulsiveness, affective lability, and self-esteem were available in subsamples. We performed linear and logistic regressions, and conducted mediation analyses in PROCESS. All analyses were as standard adjusted for age, sex, and diagnostic group.

RESULTS

Experience of one or more subtypes of childhood trauma was significantly associated with smoking tobacco in SMDs (p = 0.002). There were no significant associations between childhood trauma and amount of tobacco smoking. Cognitive control and impulsiveness were significant mediators between childhood trauma and tobacco smoking.

CONCLUSIONS

These findings indicate the experience of childhood trauma as a predisposing factor for tobacco smoking in SMDs. Cognitive control and impulsiveness were suggested as mediating mechanisms, indicating the importance of considering inhibition related self-regulatory aspects in efforts to improve health behavior in individuals with SMDs and childhood trauma.

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.

Retrospectively assessed childhood trauma experiences are associated with illness severity in mental disorders adjusted for symptom state

Converging evidence suggests that childhood trauma is a causal factor in schizophrenia (SZ) and in bipolar disorders (BD). Here, we investigated whether retrospective reports are associated with severity of illness, independent of current symptom state in a large sample of participants with SZ or BD. We included 1260 individuals (SZ [n = 461], BD [n = 352]), and healthy controls; HC [n = 447]) recruited from the same catchment area. A history of childhood trauma was obtained with the Childhood Trauma Questionnaire (CTQ). Diagnosis and episodes were obtained with the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I). Clinical symptoms (state) were assessed with the Positive and Negative Syndrome scale (PANSS), the Calgary Depression Scale (CDSS). Trait related illness characteristics were assessed with age at illness onset, number of episodes, and lifetime suicide attempts. Patients who reported multiple types of childhood trauma experiences had significantly more severe illness course including an earlier illness onset, more mood episodes, and increased risk of at least one suicide attempt, also after adjusting for current symptom state. Retrospective assessed childhood trauma experiences are associated with illness severity in mental disorders adjusted for symptom state. Our results strengthen the role of childhood trauma in development of psychopathology.

Environmental Risk Factors and Cognitive Outcomes in Psychosis: Pre-, Perinatal, and Early Life Adversity

Risk for psychosis begins to accumulate as early as the fetal period through exposure to obstetric complications like fetal hypoxia, maternal stress, and prenatal infection. Stressors in the postnatal period, such as childhood trauma, peer victimization, and neighborhood-level adversity, further increase susceptibility for psychosis. Cognitive difficulties are among the first symptoms to emerge in individuals who go on to develop a psychotic disorder. We review the relationship between pre-, perinatal, and early childhood adversities and cognitive outcomes in individuals with psychosis. Current evidence shows that the aforementioned environmental risk factors may be linked to lower overall intelligence and executive dysfunction, beginning in the premorbid period and persisting into adulthood in individuals with psychosis. It is likely that early life stress contributes to cognitive difficulties in psychosis through dysregulation of the body's response to stress, causing changes such as increased cortisol levels and chronic immune activation, which can negatively impact neurodevelopment. Intersectional aspects of identity (e.g., sex/gender, race/ethnicity), as well as gene-environment interactions, likely inform the developmental cascade to cognitive difficulties throughout the course of psychotic disorders and are reviewed below. Prospective studies of birth cohorts will serve to further clarify the relationship between early-life environmental risk factors and cognitive outcomes in the developmental course of psychotic disorders. Specific methodological recommendations are provided for future research.

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.

Childhood trauma and cardiometabolic risk in severe mental disorders: The mediating role of cognitive control

Background

Cardiometabolic risk is increased in severe mental disorders (SMDs), and there appears to be a relationship between childhood trauma and cardiometabolic risk, possibly related to adverse health behavior. The current study examined the association between childhood trauma and serum lipids and adiposity in SMDs and the potential mediating role of cognitive and personality characteristics.

Methods

Participants with schizophrenia and bipolar spectrum disorders (N = 819) were included, cardiometabolic risk factors (serum lipids, body mass index, and waist circumference) were measured, and history of childhood trauma was assessed by the Childhood Trauma Questionnaire. Cognitive and personality characteristics were available in subsamples, with assessments of cognitive control, impulsiveness, self-esteem, and affective lability. Linear regressions and mediation analyses with Hayes’ PROCESS were performed, adjusting for age, sex, antipsychotic agent propensity of metabolic side-effect, and diagnostic group.

Results

Experience of three or more subtypes of childhood trauma was positively associated with waist circumference in patients with SMDs (p = 0.014). There were no other significant associations between trauma variables and lipid or adiposity measures in the total sample. Cognitive control was a significant mediator between experience of one or two subtypes of childhood trauma and waist circumference.

Conclusions

The results indicate childhood trauma as a predisposing factor for increased waist circumference in individuals with SMDs. Poorer cognitive control, suggestive of adverse health behavior, might be a mediating factor of the association, and the findings indicate the potential importance of increased focus on these factors in prevention and treatment regimens targeting cardiometabolic health.

Childhood Trauma Is Nominally Associated With Elevated Cortisol Metabolism in Severe Mental Disorder

OBJECTIVE

Individuals exposed to childhood trauma display longstanding modifications of the Hypothalamic-Pituitary-Adrenal (HPA) axis, as well as cognitive impairments. Schizophrenia spectrum disorder (SZ) and bipolar disorders (BD) are characterised by higher prevalence of childhood trauma, abnormal HPA axis, and cognitive dysfunction. Elevated cortisol metabolism was recently demonstrated in both disorders. However, it is yet to be established if childhood adversity is associated with cortisol metabolism in this population, and how this may be associated with cognitive function.

METHODS

One-hundred-and-fourteen participants with a DSM-IV SZ or BD diagnosis took part in the study. Diagnoses were evaluated by the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). Estimated cortisol metabolizing activity (5α-reductase and 5β-reductase) was assessed by urinary free cortisol, and metabolites. All patients underwent cognitive assessment and completed the Childhood Trauma Questionnaire.

RESULTS

Estimated 5β-reductase activity was elevated in participant with childhood physical abuse (r = 0.26, p = 0.005). After adjusting for age, sex and diagnosis, physical abuse was still nominally associated with elevated 5β-reductase. Moreover, only high 5α-reductase activity was negatively correlated with working memory and executive performance (r = -0.23, p = 0.01; r = -0.19, p = 0.05, respectively), however this disappeared after adjusting for age, sex and diagnosis. Cortisol metabolism did not mediate the association between childhood trauma and cognitive function.

CONCLUSIONS

Our study indicates that childhood physical abuse is associated with elevated cortisol metabolism (5β-reductase) in adults with a SZ or BD disorder. However, our study did not support cortisol metabolism as a mediator between childhood trauma experiences and cognitive function within these disorders.

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.

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.

Reliability and validity of the Chinese version of the Childhood Trauma Questionnaire-Short Form for inpatients with schizophrenia

Background

The evaluation of childhood trauma is essential for the treatment of schizophrenia. The short form of Childhood Trauma Questionnaire (CTQ-SF) is a widely used measure of the experience of childhood trauma in the general population. Nevertheless, data regarding the psychometric property of CTQ-SF for assessing childhood trauma of patients with schizophrenia are very limited.

Methods

Two hundred Chinese inpatients with schizophrenia completed the Chinese CTQ-SF, the Child Psychological Maltreatment Scale (CPMS), the Impact of Events Scale-Revised (IES-R), and the Dissociative Experiences Scale-II (DES-II). To assess test-retest reliability of the CTQ-SF, all patients completed the CTQ-SF again two weeks later. Concurrent and convergent validity was assessed by analyzing Pearson bivariate correlation coefficients between CTQ-SF and CPMS, IES-R, and DES-II.

Results

The Cronbach’s α coefficient of the Chinese CTQ-SF was 0.81, and the two-week re-test reliability was 0.81 (P<0.01). The criterion-related validity coefficients of CTQ-SF with the CMPS, IES-R and DES-II were 0.61, 0.41, and 0.51, respectively.

Conclusion

The Chinese CTQ-SF has satisfactory psychometric properties to measure childhood abuse or neglect in Chinese inpatients with schizophrenia.

Childhood trauma in mood disorders: Neurobiological mechanisms and implications for treatment

A contemporary model for the pathogenesis of mood disorders (bipolar and depressive disorders) involves gene-environmental interaction, with genetic predisposition, epigenetic regulation, and environmental effects. Among multiple environmental factors, the experience of childhood trauma can be connected with the pathogenesis, course and the treatment of mood disorders. Patients with mood disorders have the greater frequency of childhood trauma compared with the general population, and adverse childhood experiences can exert a negative impact on their clinical course. In this article, the neurobiological mechanisms of childhood trauma are presented. The influence of negative childhood experiences on the central nervous system can result in many structural and functional changes of the brain, including such structures as hippocampus and amygdala, associated with the development of bipolar and depressive illnesses. Interaction of several genes with childhood trauma to produce pathological, clinical phenomena in adulthood has been demonstrated, the most important in this respect being the serotonin transporter gene and the FKBP5 gene playing an important role in the pathogenesis of mood disorders. Neurobiological effects can also involve epigenetic mechanisms such as DNA methylation which can exert an effect on brain function over long-term periods. Somatic effects of childhood trauma include disturbances of stress axis and immune-inflammatory mechanisms as well as metabolic dysregulation. Negative childhood experiences may also bear implications for the treatment of mood disorders. In the article, the impact of such experiences on the treatment of mood disorders will be discussed, especially in the context of treatment -resistance to antidepressants and mood-stabilizing drugs.

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.

Childhood trauma in schizophrenia spectrum disorders as compared to substance abuse disorders

The prevalence of childhood trauma (CT) in schizophrenia spectrum disorders (SSDs) and substance abuse disorders (SUDs) is high. Direct comparisons of CT in these disorders are lacking, and it is not known whether there are differences in self-reported CT in SSDs as compared to SUDs. We aimed to compare the frequency, severity and types of CT in SDDs and SUDs. Patients with SSDs (n = 57) and SUDs (n = 57) were matched for age and gender. Overall levels of CT and CT subtypes were measured retrospectively by the Childhood Trauma Questionnaire Short-Form (CTQ-SF), and grouped into none/low and moderate/severe levels of CT. Group differences in CTQ-SF sum score and subscale scores, as well as differences in the severity of overall CT and CT subtypes were all non-significant. In both groups, 64.9% reported ≥ 1 subtypes of CT above cut-off. Of those who reported CT above the cut-off, 13.5% in the psychosis group reported ≥ 4 subtypes, as compared to 2.7% in the substance abuse group. We did not find statistically significant differences between SSDs and SUDs in terms of exposure to CT frequency or severity, all effect sizes were small (r < 0.15).

Modelling gene-environment interaction in first episodes of psychosis

INTRODUCTION

Recent research demonstrates the heterogeneous etiology of psychotic disorders, where gen-environment (GxE) interaction plays a key role. Large genetic studies have linked many genetic variants with schizophrenia, but each variant is only associated with a small effect and the GxE interaction contribution has not been evaluated.

METHODS

The PEPs Project was designed to carefully collect a large amount of genetic and environmental exposure data of 335 FEP patients and 253 matched healthy controls.780single-nucleotide polymorphisms (from 159 candidate genes)and 16 environmental variables previously reported as the main psychosis non-genetic risk factors were analyzed together using entropy-based measures of information gain.

RESULTS

Our analyses identified an interaction between nine SNPs and the exposition to the environmental risk factors of psychosis, showing a clear enrichment of genes linked to serotonin neurotransmission and neurodevelopmental processes.

CONCLUSIONS

This study has allowed the identification of several GxE-environment interactions involved in the risk of presenting a FEP. Our results highlight the importance of serotonin neurotransmission interacting with certain environmental stimuli. The serotoninergic system may be playing a key role in the regulatory network of stress and other systems implicated in the emergence and development of psychotic disorders.

Effect of childhood trauma on cognitive functions in a sample of Chinese patients with schizophrenia

In this study, we aimed to determine the influence of various types of childhood trauma (CT) on cognitive functions in Chinese patients presented with schizophrenia. One hundred sixty-two patients were assessed with the Childhood Trauma Questionnaire-Short Form (CTQ-SF) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We investigated the correlations between various types of CT, demographic characteristics, and cognitive functions. Significant negative correlations were observed in physical abuse (PA) and sexual abuse (SA) with the language score (r=-0.190, -0.216, respectively, p<0.05). Similarly, physical neglect (PN) and the total score of CTQ were negatively correlated with the attention score (r=-0.17, -0.206, p<0.05, respectively) as well as the total RBANS score (r=-0.199, -0.223, respectively P<0.05). PN was also negatively correlated with delayed memory (r=-0.167, p<0.05). Regressions analysis indicated significant negative correlations between PN and attention, as well as the cognitive total score (p<0.001). Furthermore, demographic variables (years of education, family income) and clinical characteristics (type of anti-psychotics, duration of illness and times of recurrence) were correlated with cognitive functions. The current study showed that different types of CT could impact specific cognitive functions in Chinese schizophrenia patients. Therefore, we recommend that trauma-focused mental interventions for schizophrenia patients should be developed and routinely offered to patients.

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.

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.

Cognitive Impairment in Schizophrenia: Interplay of BDNF and Childhood Trauma? A Review of Literature

Cognitive impairment is a core feature of schizophrenia. These deficits can also serve as an endophenotype for the illness in genetic studies. There is evidence that suggests that cognition can be considered a reasonable target for intervention in both schizophrenia and bipolar disorder. One of the most studied genetic phenotypes for psychosis is brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms. BDNF has an established role in neuronal development and cell survival in response to stress and is abnormally expressed in schizophrenia. Studies have shown that childhood trauma is associated with poor prognosis of schizophrenic patients. BDNF-Val66Met polymorphism has been shown to moderate the impact of childhood adversity on later expression of affective symptoms, suggesting the possibility of gene environment interactions. Considering the recent advances of neuroscience an up to date review of relevant literature is warranted in this field. This article reviews the current literature available regarding associations between the Val66Met polymorphism, childhood trauma and cognitive dysfunction in schizophrenia.

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.

A history of childhood trauma is associated with slower improvement rates: Findings from a one-year follow-up study of patients with a first-episode psychosis

BACKGROUND

The aim of this study was to investigate whether childhood trauma was associated with more severe clinical features in patients with first-episode psychosis, both at the initial assessment and after one year.

METHODS

Ninety-six patients with a first-episode of a DSM-IV diagnosis of psychosis, in addition to 264 healthy controls from the same catchment area, were recruited to the TOP NORMENT study. A history of childhood trauma was obtained using the Childhood Trauma Questionnaire (CTQ). Function and symptom severity were measured using the Global Assessment of Functioning (GAF) Scale divided into function (GAF-F) and symptoms (GAF-S), the Positive and Negative Syndrome Scale (PANSS) and the Young Mania Rating Scale (YMRS). All clinical assessments were completed at two time points: At an initial assessment within the first year of initiating treatment for psychosis and after one year.

RESULTS

Childhood trauma was associated with significantly reduced global functioning and more severe clinical symptoms at both baseline and follow-up, whereas emotional neglect was associated with a significantly reduced improvement rate for global functioning (GAF-F) over the follow-up period.

CONCLUSION

Our data indicate that patients with first-episode psychosis who report a history of childhood trauma constitute a subgroup characterized by more severe clinical features over the first year of treatment, as well as slower improvement rates.

5-HTTLPR, victimization and ecological executive function of adolescents

Executive function (EF) plays an important role in guiding peer relationship, school performance and behavior control. Children exposed to traumatic environments have been reported to perform poorer in EF tasks. We explored if the relationship between victimization and EF was dependent on the functional variation 5-HTTLPR in a non-clinical sample of adolescents. Data on demographics, victimization and daily life EF were collected from school students (Han Chinese, n=2125). All those reporting executive dysfunction (n=169), and classmate controls (n=208), were genotyped for the 5-HTTLPR. It was shown that the number of victimizations associated positively with executive dysfunction (ED). This association was particularly strong in those homozygous for the short allele of 5-HTTLPR, whilst a statistical 5-HTTLPR×victimization interaction on ED was found. Our findings suggest that adolescents with a genotype conferring a low 5-HTT activity are more vulnerable to a childhood adversity-associated ED in their daily life.

The Association Between Breastfeeding Exposure and Duration, Neuropsychological Deficits, and Psychopathic Personality Traits in Offspring: The Moderating Role of 5HTTLPR

A wealth of research has revealed that a shorter duration of breastfeeding during infancy can increase the risk of various maladaptive traits, including neuropsychological deficits. Despite the number of studies that have been conducted on the topic, few studies have explored whether the effects of breastfeeding on neuropsychological functioning and personality features persist into adulthood. Furthermore, very little research to date has examined whether this relationship is moderated by specific indicators of genetic risk. The current study examines the direct and interactive effects of breastfeeding experiences and the serotonin transporter polymorphism (5HTTLPR) on neuropsychological deficits and psychopathic personality traits. Using data from the National Longitudinal study of Adolescent Health, we find that no exposure to breastfeeding and a shorter duration of breastfeeding significantly increase the risk of exhibiting neuropsychological deficits during adolescence and early adulthood as well as psychopathic personality traits during adulthood. The results also reveal a number of gene × environment interactions between 5HTTLPR, breastfeeding exposure and breastfeeding duration in the prediction of neuropsychological deficits, but not in the prediction of psychopathic personality traits.

Epigenetic alterations following early postnatal stress: a review on novel aetiological mechanisms of common psychiatric disorders

Stressor exposure during early life has the potential to increase an individual’s susceptibility to a number of neuropsychiatric conditions such as mood and anxiety disorders and schizophrenia in adulthood. This occurs in part due to the dysfunctional stress axis that persists following early adversity impairing stress responsivity across life. The mechanisms underlying the prolonged nature of this vulnerability remain to be established. Alterations in the epigenetic signature of genes involved in stress responsivity may represent one of the neurobiological mechanisms. The overall aim of this review is to provide current evidence demonstrating changes in the epigenetic signature of candidate gene(s) in response to early environmental adversity. More specifically, this review analyses the epigenetic signatures of postnatal adversity such as childhood abuse or maltreatment and later-life psychopathology in human and animal models of early life stress. The results of this review shows that focus to date has been on genes involved in the regulation of hypothalamic-pituitary-adrenal (HPA) axis and its correlation to subsequent neurobiology, for example, the role of glucocorticoid receptor gene. However, epigenetic changes in other candidate genes such as brain-derived neurotrophic factor (BDNF) and serotonin transporter are also implicated in early life stress (ELS) and susceptibility to adult psychiatric disorders. DNA methylation is the predominantly studied epigenetic mark followed by histone modifications specifically acetylation and methylation. Further, these epigenetic changes are cell/tissue-specific in regulating expression of genes, providing potential biomarkers for understanding the trajectory of early stress-induced susceptibility to adult psychiatric disorders.

Perinatal Risks and Childhood Premorbid Indicators of Later Psychosis: Next Steps for Early Psychosocial Interventions

Schizophrenia and affective psychoses are debilitating disorders that together affect 2%-3% of the adult population. Approximately 50%-70% of the offspring of parents with schizophrenia manifest a range of observable difficulties including socioemotional, cognitive, neuromotor, speech-language problems, and psychopathology, and roughly 10% will develop psychosis. Despite the voluminous work on premorbid vulnerabilities to psychosis, especially on schizophrenia, the work on premorbid intervention approaches is scarce. While later interventions during the clinical high-risk (CHR) phase of psychosis, characterized primarily by attenuated positive symptoms, are promising, the CHR period is a relatively late phase of developmental derailment. This article reviews and proposes potential targets for psychosocial interventions during the premorbid period, complementing biological interventions described by others in this Special Theme issue. Beginning with pregnancy, parents with psychoses may benefit from enhanced prenatal care, social support, parenting skills, reduction of symptoms, and programs that are family-centered. For children at risk, we propose preemptive early intervention and cognitive remediation. Empirical research is needed to evaluate these interventions for parents and determine whether interventions for parents and children positively influence the developmental course of the offspring.

Anomalous self-experience and childhood trauma in first-episode schizophrenia

BACKGROUND

Anomalous self-experiences (ASEs) are viewed as core features of schizophrenia. Childhood trauma (CT) has been postulated as a risk factor for developing schizophrenia.

AIM

The aim of this study is to investigate the relationships between CT, depression and ASEs in schizophrenia.

METHOD

ASEs were assessed in 55 patients in the early treated phases of schizophrenia using the Examination of Anomalous Self-Experience (EASE) instrument. Data on CT were collected using the Childhood Trauma Questionnaire, short form (CTQ-SF). This consists of 5 subscales: physical abuse, sexual abuse, emotional abuse, emotional neglect, and physical neglect. Assessment of depression was based on the Calgary Depression Scale for Schizophrenia (CDSS).

RESULTS

We found significant associations between EASE total score and CTQ total score and between EASE total score and emotional neglect subscore in women, but not men. We also found significant associations between CDSS total score and CTQ total score and between CDSS total score and emotional abuse, emotional neglect, and physical neglect subscores in women, but not men. In men we did not find any significant associations between EASE total score, CDSS total score and any CTQ scores.

CONCLUSION

CT was significantly associated with higher levels of ASEs in women in the early treated phases of schizophrenia, but not in men. This again associated with an increase in depressive symptoms.

Childhood trauma mediates the association between ethnic minority status and more severe hallucinations in psychotic disorder

BACKGROUND

Ethnic minority status and childhood trauma are established risk factors for psychotic disorders. Both are found to be associated with increased level of positive symptoms, in particular auditory hallucinations. Our main aim was to investigate the experience and effect of childhood trauma in patients with psychosis from ethnic minorities, hypothesizing that they would report more childhood trauma than the majority and that this would be associated with more current and lifetime hallucinations.

METHOD

In this cross-sectional study we included 454 patients with a SCID-I DSM-IV diagnosis of non-affective or affective psychotic disorder. Current hallucinations were measured with the Positive and Negative Syndrome Scale (P3; Hallucinatory Behaviour). Lifetime hallucinations were assessed with the SCID-I items: auditory hallucinations, voices commenting and two or more voices conversing. Childhood trauma was assessed with the Childhood Trauma Questionnaire, self-report version.

RESULTS

Patients from ethnic minority groups (n = 69) reported significantly more childhood trauma, specifically physical abuse/neglect, and sexual abuse. They had significantly more current hallucinatory behaviour and lifetime symptoms of hearing two or more voices conversing. Regression analyses revealed that the presence of childhood trauma mediated the association between ethnic minorities and hallucinations.

CONCLUSIONS

More childhood trauma in ethnic minorities with psychosis may partially explain findings of more positive symptoms, especially hallucinations, in this group. The association between childhood trauma and these first-rank symptoms may in part explain this group's higher risk of being diagnosed with a schizophrenia-spectrum diagnosis. The findings show the importance of childhood trauma in symptom development in psychosis.

Interplay between childhood trauma and BDNF val66met variants on blood BDNF mRNA levels and on hippocampus subfields volumes in schizophrenia spectrum and bipolar disorders

OBJECTIVE

Here we investigated a two hit gene environment model in relation to functional genomic factors (BDNF mRNA), and volume of hippocampal subfields in schizophrenia spectrum and bipolar disorders, focusing on both an environmental (childhood trauma) and genetic risk factor (BDNF val66met).

METHOD

A total of 323 patients with a broad DSM-IV schizophrenia spectrum disorder or bipolar disorder were consecutively recruited. A history of childhood trauma was obtained using the Childhood Trauma Questionnaire. BDNF DNA and RNA were analyzed using standardized procedures. A subsample of n = 108 underwent MRI scanning, and the FreeSurfer was used to obtain measures of hippocampal subfield. All MRI data were corrected for age and gender, with post-hoc analysis correcting for ICV.

RESULTS

A history of childhood trauma or being a met carrier of the BDNF val66met was associated with significantly reduced BDNF mRNA level. Additive effects were observed between a history of childhood trauma and BDNF val66met, in the direction of met carriers with high levels of childhood trauma having the lowest BDNF mRNA levels. Lastly, met carriers reporting high levels of childhood trauma (specifically sexual or physical abuse) had significantly reduced hippocampal subfield volumes CA2/3 and CA4 dentate gyrus.

CONCLUSION

The current findings demonstrate that the reduced BDNF mRNA levels found in psychosis may be associated with both a history of childhood trauma and BDNF val66met variants. Further, our study supports a two hit model including a history of childhood trauma as well as genetic vulnerability (met carriers of the BDNF val66met) behind reduced volume of hippocampal subfields in psychosis. This was specifically found for areas important for neurogenesis, the CA2/3 and the CA4 DG.

Brain derived Neurotropic Factor (BDNF) is associated with childhood abuse but not cognitive domains in first episode psychosis

BACKGROUND

The Brain-derived Neurotrophic Factor (BDNF) modulates cognitive processes and is associated with increased risk of schizophrenia. Childhood trauma (CT) is frequent in patients with psychosis and severely affects course and outcome.

AIMS

We investigated the hypothesis that BDNF is associated with both CT and cognitive deficits in a sample of first-episode psychosis (FEP) cases and unaffected controls.

METHOD

Participants with FEP and healthy controls were recruited between August 2008 and July 2011 from South London, UK. Childhood traumatic events were detected using the Childhood Experience of Care and Abuse Questionnaire (CECA-Q). Neuropsychological data were also collected. BDNF plasma levels were measured from fasting blood samples.

RESULTS

Data were available on 87 FEP patients and 152 controls. Our results showed a significant effect of separation (F=5.5; df=1,115; p=.02), physical (F=4.7; df=1, 118; p=.03) and sexual abuse (F=5.4; df=1,117; p=.02) on BDNF levels with lower levels among those who experienced the traumatic event compared to those who did not. Physical abuse predicted lower plasma levels of BDNF (β=-.30; p=.03) whereas sexual and/or physical abuse showed a trend (β=-.26; p=.06) in FEP patients but not in unaffected controls. No association between BDNF plasma levels and cognitive functions was found among patients with FEP and controls.

CONCLUSION

Our findings suggest the possible involvement of BDNF in the onset of first-episode psychosis in individuals exposed to early trauma and propose BDNF as a potential clinical biomarker to detect the detrimental effects of CT on human brain plasticity.

Affective lability in patients with bipolar disorders is associated with high levels of childhood trauma

This study aimed to investigate associations between a history of childhood trauma and levels of affective lability in bipolar patients compared to controls. Forty-two patients and 14 controls were assessed using the Affective Lability Scale (ALS) and the Childhood Trauma Questionnaire (CTQ). Affective Lability Score was significantly associated with scores on the Childhood Trauma Questionnaire. A multivariate regression model indicated a relationship between childhood trauma scores and differences in affective lability between patients and controls.

An update on the interaction between the serotonin transporter promoter variant (5-HTTLPR), stress and depression, plus an exploration of non-confirming findings

In the three years since the most recent meta-analysis of the association between the serotonin transported promoter polymorphism (5-HTTLPR), stress and the development of depression, another 27 studies have been published on this issue, which is an increase of 50% more studies than were previously reviewed. In addition, previous findings of inconsistency of results across studies argued for further exploration of this relationship. From the 81 studies identified to June 2013, the significant relationship between the short form of the 5-HTTLPR was confirmed (p=.0000009), which is stronger than the relationship reported in the most recent meta-analysis in 2011. However, nearly 26% of the 81 studies reviewed failed to show any significant association between the 5-HTTLPR, stress and depression, and four studies found opposite results to those expected. Examination of the methodologies of all studies failed to indicate any flaws in the opposite or unequivocal studies, and the latter had larger sample sizes than those studies which supported the expected association, arguing that the null results were not an outcome of insufficient statistical power. The need to consider aspects of samples and measures of depression, particularly the presence of subtypes of depression in future research is discussed.

Recent advances in understanding schizophrenia

Schizophrenia is a highly disabling disorder whose causes remain to be better understood, and treatments have to be improved. However, several recent advances have been made in diagnosis, etiopathology, and treatment. Whereas reliability of diagnosis has improved with operational criteria, including Diagnostic and Statistical Manual of Mental Disorders, (DSM) Fifth Edition, validity of the disease boundaries remains unclear because of substantive overlaps with other psychotic disorders. Recent emphasis on dimensional approaches and translational bio-behavioral research domain criteria may eventually help move toward a neuroscience-based definition of schizophrenia. The etiology of schizophrenia is now thought to be multifactorial, with multiple small-effect and fewer large-effect susceptibility genes interacting with several environmental factors. These factors may lead to developmentally mediated alterations in neuroplasticity, manifesting in a cascade of neurotransmitter and circuit dysfunctions and impaired connectivity with an onset around early adolescence. Such etiopathological understanding has motivated a renewed search for novel pharmacological as well as psychotherapeutic targets. Addressing the core features of the illness, such as cognitive deficits and negative symptoms, and developing hypothesis-driven early interventions and preventive strategies are high-priority goals for the field. Schizophrenia is a severe, chronic mental disorder and is among the most disabling disorders in all of medicine. It is estimated by the National Institute of Mental Health (NIMH) that 2.4 million people over the age of 18 in the US suffer from schizophrenia. This illness typically begins in adolescence and derails the formative goals of school, family, and work, leading to considerable suffering and disability and reduced life expectancy by about 20 years. Treatment outcomes are variable, and some people are successfully treated and reintegrated (i.e. go back to work). Despite the effort of many experts in the field, however, schizophrenia remains a chronic relapsing and remitting disorder associated with significant impairments in social and vocational functioning and a shortened lifespan. Comprehensive treatment entails a multi-modal approach, including psychopharmacology, psychosocial interventions, and assistance with housing and financial sustenance. Research to date suggests a network of genetic, neural, behavioral, and environmental factors to be responsible for its development and course. This article aims to summarize and explain recent advancements in research on schizophrenia, to suggest how these recent discoveries may lead to a better understanding and possible further development of effective therapies, and to highlight the paradigm shifts that have taken place in our understanding of the diagnosis, etiopathology, and treatment.

Additive effects of childhood abuse and cannabis abuse on clinical expressions of bipolar disorders

BACKGROUND

Previous studies of bipolar disorders indicate that childhood abuse and substance abuse are associated with the disorder. Whether both influence the clinical picture, or if one is mediating the association of the other, has not previously been investigated.

METHOD

A total of 587 patients with bipolar disorders were recruited from Norway and France. A history of childhood abuse was obtained using the Childhood Trauma Questionnaire. Diagnosis and clinical variables, including substance abuse, were based on structured clinical interviews (Structured Clinical Interview for DSM-IV Axis I disorders or French version of the Diagnostic Interview for Genetic Studies).

RESULTS

Cannabis abuse was significantly associated with childhood abuse, specifically emotional and sexual abuse (χ 2 = 8.63, p = 0.003 and χ 2 = 7.55, p = 0.006, respectively). Cannabis abuse was significantly associated with earlier onset of the illness (z = -4.17, p < 0.001), lifetime history of at least one suicide attempt (χ 2 = 11.16, p = 0.001) and a trend for rapid cycling (χ 2 = 3.45, p = 0.06). Alcohol dependence was associated with suicide attempt (χ 2 = 10.28, p = 0.001), but not with age at onset or rapid cycling. After correcting for possible confounders and multiple testing, a trend was observed for an interaction between cannabis abuse and childhood abuse and suicide attempt (logistic regression: r 2 = 0.06, p = 0.039). Significant additive effects were also observed between cannabis abuse and childhood abuse on earlier age at onset (p < 0.001), increased rapid cycling and suicide attempt (logistic regression: r 2 = 0.03-0.04, p < 0.001). No mediation effects were observed; childhood abuse and cannabis abuse were independently associated with the disorder.

CONCLUSIONS

Our study is the first to demonstrate significant additive effects, but no mediation effects, between childhood abuse and cannabis abuse on increased clinical expressions of bipolar disorders.

Environmental factors during adolescence associated with later development of psychotic disorders - a nested case-control study

Etiologies of psychotic disorders (schizophrenia and bipolar disorder) are conceptualized as interplay between genetic and environmental factors. The adolescent period is characterized by changes in social roles and expectations that may interact with biological changes or psychosocial stressors. Few studies focus on the adolescents' own reports of perceived risk factors. To assess differences at age 16 between persons who later develop psychotic disorders ("Confirmed Psychosis", CP) and their class-mates ("Population Controls", PC) we collected information on: (1) Social support factors (size of social network and expectancies of social support from friends), (2) Cognitive functioning (concentrating in the classroom, actual grades and expectancies of own academic achievements) and (3) Problems and stressors in families (illness or loss of work for parents), and in relationship with others (exposure to bullying, violence or sexual violation). Self-reported data from students at 15-16 years of age were linked to the case-registers from the "Thematically Organized Psychosis (TOP) Study". The CP group reported more economic problems in their families, smaller social network and lower academic expectation than the PC group. The results support the notion that long-term socioeconomic stressors in adolescence may serve as risk factors for the development of psychotic disorders.

Catechol-O-methyltransferase (COMT) genotype moderates the effects of childhood trauma on cognition and symptoms in schizophrenia

The interaction of genetic and environmental factors may affect the course and development of psychotic disorders. We examined whether the effects of childhood trauma on cognition and symptoms in schizophrenia were moderated by the Catechol-O-methyltransferase (COMT) Val(158)Met polymorphism, a common genetic variant known to affect cognition and prefrontal dopamine levels. Participants were 429 schizophrenia/schizoaffective cases from the Australian Schizophrenia Research Bank (ASRB). Cognitive performance was assessed using the Repeatable Battery for Assessment of Neuropsychological Status (RBANS), Controlled Oral Word Association Test (COWAT), Letter Number Sequencing (LNS) test, and the Wechsler Test of Adult Reading (WTAR). Hierarchical regression was used to test the main effects and additive interaction effects of genotype and childhood trauma in the domains of physical abuse, emotional abuse, and emotional neglect, on cognition and symptom profiles of clinical cases. Consistent with previous findings, COMT Val homozygotes performed worse on cognitive measures in the absence of childhood adversity. In addition, a significant interaction between COMT genotype and physical abuse was associated with better executive function in Val homozygotes, relative to those of the same genotype with no history of abuse. Finally, the severity of positive symptoms was greater in Met carriers who had experienced physical abuse, and the severity of negative symptoms in Met carriers was greater in the presence of emotional neglect. These results suggest that the possible epigenetic modulation of the expression of the COMT Val(158)Met polymorphism and consequent effects on cognition and symptoms in schizophrenia, with worse outcomes associated with adverse childhood experiences in Met carriers.

A systematic review of cognitive function in first-episode psychosis, including a discussion on childhood trauma, stress, and inflammation

OBJECTIVE

To carry out a systematic review of the literature addressing cognitive functions in first-episode psychosis (FEP), divided into domains. Although this is not a full "cognitive-genetics-in-schizophrenia review," we will also include putative ideas of mechanism(s) behind these impairments, focusing on how early stress, and genetic vulnerability may moderate cognitive function in psychosis.

METHOD

Relevant studies were identified via computer literature searches for research published up to and including January 2013, only case-control studies were included for the neurocognitive meta-analysis.

RESULTS

Patients with FEP present global cognitive impairment compared to healthy controls. The largest effect size was observed for verbal memory (Cohen's d effect size = 2.10), followed by executive function (effect size = 1.86), and general IQ (effect size = 1.71). However, effect sizes varied between studies.

CONCLUSION

Cognitive impairment across domains, up to severe level based on Cohen's effect size, is present already in FEP studies. However, differences in levels of impairment are observed between studies, as well as within domains, indicating that further consolidation of cognitive impairment over the course of illness may be present. Cognitive abnormalities may be linked to a neurodevelopmental model including increased sensitivity to the negative effect of stress, as well as genetic vulnerability. More research on this field is needed.

Gene-environment interactions in severe mental illness

Severe mental illness (SMI) is a broad category that includes schizophrenia, bipolar disorder, and severe depression. Both genetic disposition and environmental exposures play important roles in the development of SMI. Multiple lines of evidence suggest that the roles of genetic and environmental factors depend on each other. Gene-environment interactions may underlie the paradox of strong environmental factors for highly heritable disorders, the low estimates of shared environmental influences in twin studies of SMI, and the heritability gap between twin and molecular heritability estimates. Sons and daughters of parents with SMI are more vulnerable to the effects of prenatal and postnatal environmental exposures, suggesting that the expression of genetic liability depends on environment. In the last decade, gene-environment interactions involving specific molecular variants in candidate genes have been identified. Replicated findings include an interaction between a polymorphism in the AKT1 gene and cannabis use in the development of psychosis and an interaction between the length polymorphism of the serotonin transporter gene and childhood maltreatment in the development of persistent depressive disorder. Bipolar disorder has been underinvestigated, with only a single study showing an interaction between a functional polymorphism in the BDNF gene and stressful life events triggering bipolar depressive episodes. The first systematic search for gene-environment interactions has found that a polymorphism in CTNNA3 may sensitize the developing brain to the pathogenic effect of cytomegalovirus in utero, leading to schizophrenia in adulthood. Strategies for genome-wide investigations will likely include coordination between epidemiological and genetic research efforts, systematic assessment of multiple environmental factors in large samples, and prioritization of genetic variants.

No evidence for association between bipolar disorder risk gene variants and brain structural phenotypes

BACKGROUND

While recent genome-wide association studies have identified several new bipolar disorder (BD) risk variants, structural imaging studies have reported enlarged ventricles and volumetric reductions among the most consistent findings. We investigated whether these genetic risk variants could explain some of the structural brain abnormalities in BD.

METHODS

In a sample of 517 individuals (N=121 BD cases, 116 SZ cases, 61 other psychosis cases and 219 healthy controls), we tested the potential association between nine SNPs in the genes CACNA1C, ANK3, ODZ4 and SYNE1 and eight brain structural measures found to be altered in BD, and if these were specifically affecting the BD sample. We also assessed the polygenic effect of all these 9 SNPs on the brain phenotypes.

RESULTS

Our most significant result was an association between the risk allele A in CACNA1C SNP rs4775913 and decreased cerebellar volume (pnom.=0.0075) in the total sample, which did not remain significant after multiple testing correction (pthreshold<0.0064). There was no evidence for diagnostic specificity for this association in the BD group. Further, no polygenic effect of these 9 SNPs was observed.

LIMITATIONS

Low statistical power might increase our type II error rate.

CONCLUSIONS

The present findings indicate that these risk SNPs do not explain a large proportion of the structural brain alterations in BD. Thus, these genes which are all related to neuronal functions must be involved in other pathophysiological aspects of BD development.

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

OBJECTIVE

Brain derived neurotrophic factor (BDNF) is important for brain development and plasticity, and here we tested if the functional BDNF val66met variant modulates the association between high levels of childhood abuse, cognitive function, and brain abnormalities in psychoses.

METHOD

249 patients with a broad DSM-IV schizophrenia spectrum disorder or bipolar disorder were consecutively recruited to the TOP research study (mean±age: 30.7±10.9; gender: 49% males). History of childhood trauma was obtained using the Childhood Trauma Questionnaire. Cognitive function was assessed through a standardized neuropsychological test battery. BDNF val66met was genotyped using standardized procedures. A sub-sample of n=106 Caucasians with a broad DSM-IV schizophrenia spectrum disorder or bipolar disorder (mean±age: 32.67±10.85; 49% males) had data on sMRI.

RESULTS

Carriers of the Methionine (met) allele exposed to high level of childhood abuse demonstrated significantly poorer cognitive functioning compared to homozygotic Valine (val/val) carriers. Taking in consideration multiple testing, using a more conservative p value, this was still shown for physical abuse and emotional abuse, as well as a trend level for sexual abuse. Further, met carriers exposed to high level of childhood sexual abuse showed reduced right hippocampal volume (r(2)=0.43; p=0.008), and larger right and left lateral ventricles (r(2)=0.37; p=0.002, and r(2)=0.27; p=0.009, respectively). Our findings were independent of age, gender, diagnosis and intracranial volume.

CONCLUSION

Our data demonstrate that in patients with psychoses, met carriers of the BDNF val66met with high level of childhood abuse have more cognitive and brain abnormalities than all other groups.

The long-term impact of early adversity on late-life psychiatric disorders

Early adversity is a strong and enduring predictor of psychiatric disorders including mood disorders, anxiety disorders, substance abuse or dependence, and posttraumatic stress disorder. However, the mechanisms of this effect are not well understood. The purpose of this review is to summarize and integrate the current research knowledge pertaining to the long-term effects of early adversity on psychiatric disorders, particularly in late life. We explore definitional considerations including key dimensions of the experience such as type, severity, and timing of adversity relative to development. We then review the potential biological and environmental mediators and moderators of the relationships between early adversity and psychiatric disorders. We conclude with clinical implications, methodological challenges and suggestions for future research.

Patterns of childhood adverse events are associated with clinical characteristics of bipolar disorder

BACKGROUND

Previous studies in bipolar disorder investigating childhood trauma and clinical presentations of the illness have mainly focused on physical and sexual abuse. Our aim was to explore further the relationship between childhood trauma and disease characteristics in bipolar disorder to determine which clinical characteristics were most strongly associated with childhood trauma total score, as well as subtypes of adverse childhood events, including physical, sexual, emotional abuse and neglect.

METHODS

141 Patients with bipolar disorder were consecutively recruited, and disease history and clinical characteristics were assessed. History of childhood abuse was obtained using the Childhood Trauma Questionnaire (CTQ). Statistical methods used were factor analysis, Poisson and linear regression, and generalized additive modeling (GAM).

RESULTS

The factor analysis of CTQ identified three factors: emotional abuse/neglect, sexual abuse and physical abuse. There were significant associations between CTQ total score and earlier onset of illness, reduced level of psychosocial functioning (GAF; Global Assessment of Functioning) and decreased number of hospitalization, which mainly were due to the factor emotional abuse/neglect. Physical abuse was significantly associated with lower GAF scores, and increased number of mood episodes, as well as self-harm. Sexual abuse was significantly associated with increased number of mood episodes. For mood episodes and self-harm the associations were characterized by great variance and fluctuations.

CONCLUSIONS

Our results suggest that childhood trauma is associated with a more severe course of bipolar illness. Further, childhood abuse (physical and sexual), as well as emotional abuse and neglect were significantly associated with accelerating staging process of bipolar disorder. By using specific trauma factors (physical abuse, sexual abuse and emotional abuse/neglect) the associations become both more precise, and diverse.

Psychometric properties of the Childhood Trauma Questionnaire-Short Form (CTQ-SF) in Korean patients with schizophrenia

OBJECTIVE

Despite increasing interest in the relationship between childhood trauma and psychosis, measures used to assess early trauma have not had their psychometric properties extensively tested among individuals with serious mental illness. This study investigated the reliability and validity of one of the most widely-used self-reports of early adversity, the Childhood Trauma Questionnaire, Short Form (CTQ), among patients with schizophrenia.

METHODS

The CTQ was administered to 100 patients (52 inpatients and 48 outpatients) diagnosed with schizophrenia in three training hospitals. Internal consistency, four-week test-retest reliability and validity were calculated. Participants also completed the Trauma Antecedents Questionnaire (TAQ), the Impact of Events Scale-Revised (IES-R), and the Dissociative Experiences Scale-Taxon (DES-T).

RESULTS

Our analysis indicated high test-retest reliability (Spearman ρ=0.75) and internal consistency (Cronbach α=0.89). Concurrent validity was confirmed as each type of childhood trauma was significantly correlated with the corresponding subscales of the TAQ. In addition, the CTQ was positively related to post-traumatic stress symptoms and pathological dissociation, demonstrating the convergent validity of the scale.

CONCLUSION

The CTQ is a reliable and valid self-report measure for assessing childhood trauma in both inpatients and outpatients with schizophrenia.

Childhood trauma as a cause of psychosis: linking genes, psychology, and biology

Recent studies have provided robust evidence for an association between childhood trauma (CT) and psychosis. Meta-analyses have quantified the association, pointing to odds ratios in the order of around 3, and prospective studies have shown that reverse causation is unlikely to explain the association. However, more work is needed to address the possibility of a gene-environment correlation, that is, whether genetic risk for psychosis predicts exposure to CT. Nevertheless, multiple studies have convincingly shown that the association between CT and psychosis remains strong and significant when controlling for genetic risk, in agreement with a possible causal association. In addition, several studies have shown plausible psychological and neurobiological mechanisms linking adverse experiences to psychosis, including induction of social defeat and reduced self-value, sensitization of the mesolimbic dopamine system, changes in the stress and immune system, and concomitant changes in stress-related brain structures, such as the hippocampus and the amygdala, findings that should be integrated, however, in more complex models of vulnerability. It is currently unclear whether genetic vulnerability plays a role in conferring the mental consequences of adversity, and which genes are likely to be involved. The current, limited evidence points to genes that are not specifically involved in psychosis but more generally in regulating mood (serotonin transporter gene), neuroplasticity (brain-derived neurotrophic factor), and the stress-response system (FKBP5), in line with a general effect of CT on a range of mental disorders, rather than suggesting specificity for psychosis.

[Trauma and psychosis--part 2. On the association of early childhood maltreatment and risk of psychosis in general population]

Any association of early childhood maltreatment and later risk of psychosis may be favourably investigated by epidemiological studies in the general population. Primary outcome variable in these studies is the prevalence of subclinical psychotic symptoms (hallucinations, delusions) in early trauma-exposed groups compared to control groups without any significant trauma in childhood. A systematic literature search underlines a significant association of early childhood trauma and later non-clinical psychotic symptoms in representative samples of the general population both during childhood, adolescence and adulthood. Important questions deal with the issues, which psychological, psychosocial and neurobiological mechanisms may mediate the risk of early trauma in respect of later psychotic symptoms on the one side, and which factors may determine the transition from non-clinical psychotic symptoms to major psychotic disorders cared for within mental health services. Both theoretical models and first data derived from empirical studies will be presented.

Is cognitive impairment following early life stress in severe mental disorders based on specific or general cognitive functioning?

Schizophrenia spectrum and bipolar disorder are characterized by high levels of childhood trauma as well as of cognitive dysfunction. Our aim is to investigate the association between these two factors in the largest study in the literature so far. A total of 406 patients with schizophrenia spectrum- or bipolar disorders were recruited from a catchment area based organization in Oslo, Norway. Information about early life stress was obtained using the Childhood Trauma Questionnaire (CTQ). Cognitive function was assessed through a comprehensive and standardized neuropsychological test battery. Physical abuse, sexual abuse and physical neglect were significantly associated with reduced scores on working memory and executive function scales (p=0.04 to p<0.001), and verbal and performance tasks from the Wechsler Abbreviated Scale of Intelligence (WASI) (p=0.059 to p<0.001). When verbal and performance tasks from the WASI were added into a multivariate regression model, the association between CTQ and the specific cognitive domains decreased, and only WASI scores remained statistically significant. Our results indicate that childhood trauma is associated with a reduction in cognitive function across cognitive domains in patients with schizophrenia spectrum- and bipolar disorders, in particular working memory and executive function as well as general cognition. Moreover, these dysfunctions seem to be driven by underlying deficits in general cognitive tasks as measured by the WASI.

Association of the 5-HTT gene-linked promoter region (5-HTTLPR) polymorphism with psychiatric disorders: review of psychopathology and pharmacotherapy

Serotonin (5-HT) regulates important biological and psychological processes including mood, and may be associated with the development of several psychiatric disorders. An association between psychopathology and genes that regulate 5-HT neurotransmission is a robust area of research. Identification of the genes responsible for the predisposition, development, and pharmacological response of various psychiatric disorders is crucial to the advancement of our understanding of their underlying neurobiology. This review highlights research investigating 5-HT transporter (5-HTTLPR) polymorphism, because studies investigating the impact of the 5-HTTLPR polymorphism have demonstrated significant associations with many psychiatric disorders. Decreased transcriptional activity of the S allele ("risk allele") may be associated with a heightened amygdala response leading to anxiety-related personality traits, major depressive disorder, suicide attempts, and bipolar disorder. By contrast, increased transcriptional activity of the L allele is considered protective for depression but is also associated with completed suicide, nicotine dependence, and attention deficit hyperactivity disorder. For some disorders, such as post-traumatic stress disorder and major depressive disorder, the research suggests that treatment response may vary by allele (such as an enhanced response to serotonin specific reuptake inhibitors in patients with major depressive disorder and post-traumatic stress disorder with L alleles), and for alcohol dependence, the association and treatment for S or L alleles may vary with alcoholic subtype. While some studies suggest that 5-HTTLPR polymorphism can moderate the response to pharmacotherapy, the association between 5-HTTLPR alleles and therapeutic outcomes is inconsistent. The discovery of triallelic 5-HTTLPR alleles (L(A)/L(G)/S) may help to explain some of the conflicting results of many past association studies, while concurrently providing more meaningful data in the future. Studies assessing 5-HTTLPR as the solitary genetic factor contributing to the etiology of psychiatric disorders continue to face the challenges of statistically small effect sizes and limited replication.