Environment and schizophrenia: environmental factors in schizophrenia: childhood trauma--a critical review

Childhood trauma and dissociation in first-episode psychosis, chronic schizophrenia and community controls

Increasing evidence supports the role of childhood trauma in the etiology of psychosis but underlying mechanisms are poorly understood. Early maltreatment has been linked to dissociative symptoms in psychosis patients. We explored associations between childhood trauma (Childhood Trauma Questionnaire) and dissociation (Dissociative Experiences Scale) in first-episode psychotic patients (n=62), chronic psychotic patients (n=43), and non-psychotic community controls (n=66). Multivariate analyses of covariance were used to test associations between childhood trauma and dissociation by group while controlling for sex. Chronic patients reported the highest level of dissociation. More severe childhood trauma was associated with greater dissociative symptoms in all groups although most strongly in chronic patients. Emotional abuse showed the strongest associations with dissociation, with these being strongest for chronic patients, followed by first-episode patients--and least for controls. Men showed a stronger association between physical neglect and dissociation than women, irrespective of group. There were no significant group by sex interactions. Our findings replicate the strong association between childhood trauma and dissociative symptoms in chronic and first-episode psychotic patients relative to non-psychotic control subjects. We also demonstrate the salience of emotional abuse in explaining variance in dissociation, especially in chronic patients.

Prevalence of self-reported childhood abuse in psychosis: a meta-analysis of retrospective studies

There is extensive clinical literature reporting traumatic childhood experiences in patients with psychosis. A quantitative meta-analysis addressing the prevalence of self-reported childhood sexual (CSA), physical (CPA) and emotional abuse (CEA) in psychotic patients has yet to be done. We conducted, a systematic literature search to identify retrospective studies addressing self-reported childhood abuse in patients with DSM/ICD psychosis. Demographic, clinical, and methodological variables were extracted from each publication, or obtained directly from its authors. Quantitative meta-analysis of CSA, CPA, CEA in the sample of patients was performed. Statistical heterogeneity and publication bias were assessed and meta-regressions performed to control for different moderators. Twenty-three studies were retrieved and included a total of 2017 psychotic patients. The prevalence of self-reported CSA, CPA, CEA were respectively of 26%, 39% and 34%. Age, publication year, gender and substance abuse moderated CSA, while age, clinical setting and substance abuse moderated CPA. Results indicated that CEA was moderated by gender and publication year of the study. According to our meta-analysis, psychotic patients have a consistently high self-report of childhood traumatic events which are sexual, physical and emotional in nature. It is our opinion that clinicians should be trained and skilled to carefully investigate childhood abuse in psychosis.

History of trauma and the association with baseline symptoms in an Ultra-High Risk for psychosis cohort

Few studies have addressed the correlates of trauma in young people at Ultra-High Risk (UHR) of developing a psychotic disorder. We aimed to examine baseline differences in intensity, form and content of attenuated positive psychotic symptoms, other clinical symptomatology and comorbidity between UHR patients with and without a history of trauma. In a sample of 127 UHR individuals (53 male, 74 female; mean age 18.2 years, range 14-26) we assessed trauma history and baseline symptomatology using an audit tool developed to retrieve data from patient medical records. 56% of the subjects had experienced at least one type of trauma. The intensity of perceptual abnormalities was significantly higher in the group with a history of physical abuse and 'other trauma' compared to those without a trauma history. Physical abuse was related to higher levels of visual disturbances, suspiciousness, grandiose beliefs and low mood compared to those without a history of physical abuse. Sexual trauma was related to perceptual disturbances with abusive content and PTSD symptoms. The prevalence of previous trauma in people at UHR of developing psychosis is high. Our findings tentatively suggest that different types of trauma may impact differently on initial presentation to UHR services.

Relationship between the COMT-Val158Met and BDNF-Val66Met polymorphisms, childhood trauma and psychotic experiences in an adolescent general population sample

Objective

Psychotic experiences occur at a much greater prevalence in the population than psychotic disorders. There has been little research to date, however, on genetic risk for this extended psychosis phenotype. We examined whether COMT or BDNF genotypes were associated with psychotic experiences or interacted with childhood trauma in predicting psychotic experiences.

Method

Psychiatric interviews and genotyping for COMT-Val158Met and BDNF-Val66Met were carried out on two population-based samples of 237 individuals aged 11-15 years. Logistic regression was used to examine for main effects by genotype and childhood trauma, controlling for important covariates. This was then compared to a model with a term for interaction between genotype and childhood trauma. Where a possible interaction was detected, this was further explored in stratified analyses.

Results

While childhood trauma showed a borderline association with psychotic experiences, COMT-Val158Met and BDNF-Val66Met genotypes were not directly associated with psychotic experiences in the population. Testing for gene x environment interaction was borderline significant in the case of COMT-Val158Met with individuals with the COMT-Val158Met Val-Val genotype, who had been exposed to childhood trauma borderline significantly more likely to report psychotic experiences than those with Val-Met or Met-Met genotypes. There was no similar interaction by BDNF-Val66Met genotype.

Conclusion

The COMT-Val158Met Val-Val genotype may be a genetic moderator of risk for psychotic experiences in individuals exposed to childhood traumatic experiences.

The history of childhood trauma among individuals with ultra high risk for psychosis is as common as among patients with first-episode schizophrenia

AIM

Childhood trauma (CT) is more common in patients with psychosis than in general population and is found to be related to the severity of symptoms. The objective of this study was to investigate the severity of CT, and its relationship with clinical features in two different groups: first-episode schizophrenia (FES) and ultra high risk for psychosis (UHR) groups.

METHODS

In this cross-sectional study, 83 patients with FES, 41 individuals with UHR and 69 healthy controls were included. Clinical features were evaluated with the Brief Psychiatric Rating Scale, the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms (SAPS). We evaluated CT with the Childhood Trauma Questionnaire (CTQ). UHR group was also assessed with the Calgary Depression Scale for Schizophrenia.

RESULTS

The emotional and physical abuse, physical and emotionalneglect subscale scores and CTQ total score of both the UHR group and FES group were higher than the control group. However, the CTQ total score and subscale scores did not differ between FES and UHR groups. UHR group had more Schneiderian symptoms in terms of both number and severity, and severity of sexual abuse was found to be correlated with SAPS scores especially for the 'commenting voices' item. The CTQ emotional abuse and neglect scores were correlated with the severity of depression. FES patients with higher CTQ scores obtained higher total scores on SAPS and higher total scores on Schneiderian items.

CONCLUSION

We found that CT is related to the severity of psychotic symptoms in both FES and UHR groups. Therefore, it is possible that interventions aimed at preventing CT in children would reduce the manifestation of psychosis among young people.

Early maladaptive schemas predict positive symptomatology in schizophrenia: a cross-sectional study

Recent literature has shown the role of social factors, such as childhood negative experiences and attachment styles, in the genesis of psychotic symptoms. So far, despite this association with childhood negative experiences and a wide range of psychiatric disorders, no study has yet attempted to assess early maladaptive schemas (EMSs) in patients with schizophrenia as primary diagnosis. A sample of 48 patients diagnosed with schizophrenia and 44 control participants answered the schema questionnaire short form's French validation, and were assessed with the positive and negative syndrome scale as well as a scale of depression symptomatology. Results showed that, after controlling for depression, patients with schizophrenia achieved higher scores than control subjects on six EMSs. The EMSs were associated with positive, but not negative, symptomatology. After controlling for depression, only the Mistrust/Abuse schema was a significant predictor of positive symptoms accounting for a small portion (12.4%) of the variance. The results highlight the importance of focusing not only on the schizophrenic symptoms but also on the person and his or her subjective development of self. Therefore, these results suggest that Young's schema theory may be applied to schizophrenic patients.

Prevalence of bullying victimisation amongst first-episode psychosis patients and unaffected controls

BACKGROUND

Despite increasing evidence suggesting that childhood maltreatment is significantly associated with psychosis, the specific role of bullying in the onset of psychotic disorders is still unclear. This study aimed to examine whether bullying was more prevalent amongst individuals presenting to services for the first time with a psychotic disorder than in unaffected community controls.

METHODS

Data on exposure to bullying, psychotic symptoms, cannabis use and history of conduct disorder were collected cross-sectionally from 222 first-presentation psychosis cases and 215 geographically-matched controls. Bullying victimisation was assessed retrospectively as part of the Brief Life Events schedule. Logistic regression was used to examine associations between exposure to bullying and case-control status, while controlling for potential confounders.

RESULTS

Psychosis cases were approximately twice as likely to report bullying victimisation when compared to controls. No significant interactions between bullying and either gender or cannabis use were found. Controls reporting being a victim of bullying were approximately twice as likely to also report at least one psychosis-like symptom.

CONCLUSIONS

Our results extend previous research by suggesting that bullying victimisation may contribute to vulnerability to develop a psychotic disorder in some individuals.

Childhood sexual abuse increases risk of auditory hallucinations in psychotic disorders

BACKGROUND/AIMS

Previous studies point to an association between childhood sexual abuse (CSA) and auditory hallucinations (AH). However, methodological issues limit the strength of these results. Here we compared childhood abuse between psychotic disorder patients and healthy control subjects using a reliable measure of abuse, and assessed the relationship between CSA and AH.

METHODS

114 psychotic disorder patients and 81 healthy control subjects were administered the Structured Clinical Interview of the DSM-IV (SCID) and the Childhood Trauma Questionnaire (CTQ). We compared the severity of abuse between groups, and tested the relationship between different types of childhood abuse and specific psychotic symptoms.

RESULTS

Psychotic patients reported more childhood abuse than controls (p<.001). Psychotic patients with a history of AH reported significantly more sexual, emotional, and physical abuse than patients without a history of AH (p<.05). Emotional and physical abuse, in the absence of sexual abuse, did not lead to a higher rate of AH. Finally, reports of childhood abuse did not increase the risk of any form of hallucination other than AH or of any form of delusion.

CONCLUSIONS

These results suggest that childhood abuse, especially childhood sexual abuse, shapes the phenotype of psychotic disorders by conferring a specific risk for AH.

Childhood trauma and psychosis

Childhood trauma is a common occurrence and has been associated with psychosis and suggested as a risk factor leading to psychosis and schizophrenia in adulthood. This article introduces the scope of the problem and discusses the evidence for causal relationships between childhood adversities and increased risk for psychosis. The relationship between specific types of trauma and their association with specific psychotic symptoms is described, as well as the manifestations of co-occurring trauma effects and psychosis in adolescents. Clinical presentations and the use of diagnostic instruments, diagnostic comorbidities, and evidence-based psychotherapeutic interventions to treat effects of trauma in youth with psychotic illnesses are discussed.

DISC1 mouse models as a tool to decipher gene-environment interactions in psychiatric disorders

DISC1 was discovered in a Scottish pedigree in which a chromosomal translocation that breaks this gene segregates with psychiatric disorders, mainly depression and schizophrenia. Linkage and association studies in diverse populations support DISC1 as a susceptibility gene to a variety of neuropsychiatric disorders. Many Disc1 mouse models have been generated to study its neuronal functions. These mouse models display variable phenotypes, some of them relevant to schizophrenia, others to depression. The Disc1 mouse models are popular genetic models for studying gene-environment interactions in schizophrenia. Five different Disc1 models have been combined with environmental factors. The environmental stressors employed can be classified as either early immune activation or later social paradigms. These studies cover major time points along the neurodevelopmental trajectory: prenatal, early postnatal, adolescence, and adulthood. Various combinations of molecular, anatomical and behavioral methods have been used to assess the outcomes. Additionally, three of the studies sought to rescue the resulting abnormalities. Here we provide background on the environmental paradigms used, summarize the results of these studies combining Disc1 mouse models with environmental stressors and discuss what we can learn and how to proceed. A major question is how the genetic and environmental factors determine which psychiatric disorder will be clinically manifested. To address this we can take advantage of the many Disc1 models available and expose them to the same environmental stressor. The complementary experiment would be to expose the same model to different environmental stressors. DISC1 is an ideal gene for this approach, since in the Scottish pedigree the same chromosomal translocation results in different psychiatric conditions.

Association between traumatic experiences and psychosis among incarcerated men

The possible influence of traumatic experiences on subsequent manifestations of psychosis has been the subject of intense scientific debate in the last decade. Whereas some authors have found a clear association between trauma and psychosis, others have pointed out methodological deficiencies in the research or have found only weak associations. Others found no association between trauma and psychosis in exclusive samples of men and recommend the use of studies stratified by sex. This article uses the data from an epidemiological study of a random sample of 500 male inmates in two prisons in Andalusia (Spain) to analyze the association between psychosis and trauma. The inmates were diagnosed using The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) interviews by teams of experienced clinicians. The results show a clear association between traumatic events and some functional psychosis or some psychosis, including induced psychoses. These associations resist the possible effect of confusing variables such as the origin of the inmates, educational level, or having an addictive disorder. We discuss the need to pay special attention to traumatic experiences such as witnessing extreme violence against others or participating in acts of violence, particularly in men. Our results are compatible with different theories that defend the association between trauma and psychosis.

Initial evidence for sex-specific effects of early emotional abuse on affective processing in bipolar disorder

PURPOSE

This study investigates the effect of sex and childhood trauma on affective processing in bipolar disorder (BPD) patients.

METHODS

In a sample of fifty-six BPD patients, we administered the Childhood Trauma Questionnaire (CTQ), and the Iowa Gambling Task (IGT) and the Affective Go/No-Go (AGNG) to measure affective processing. Analysis of Variance (ANOVA) was used to evaluate the effect of sex and childhood trauma on IGT; Repeated-Measures ANOVAs to measure accuracy and bias measures across conditions on the AGNG.

RESULTS

In the context of childhood abuse, females evidenced a more conservative cognitive style than males by selecting fewer cards from the disadvantageous decks [F(1, 49)=14.218; P<0.001] and showed an improvement throughout the task, as noted in a normal learning curve [F(1.49)=4.385; P=0.041)]. For the AGNG, an interaction specific to the negative valence stimuli on response bias measures was found. Abused females scored higher (mean=8.38; SD=6.39) than abused males (mean=0.69; SD=1.19) [F(1.46)=6.348; P=0.015].

CONCLUSION

Severity of childhood trauma was significantly different between sexes. In the context of a history of emotional abuse, male bipolar patients tended toward a more risk-taking behavior compared to female. Further investigations are needed to elucidate potential pathophysiological mechanisms underlying this interaction.

Early traumatic experiences in those at clinical high risk for psychosis

AIM

Several lines of evidence suggest a possible association between a history of trauma in childhood and later psychosis or psychotic-like experiences. The purpose of this study was to determine the extent of childhood trauma and bullying in young people at clinical high risk (CHR) of developing psychosis.

METHODS

The sample consisted of 360 individuals who were at CHR of developing psychosis and 180 age- and gender-matched healthy controls. All participants were assessed on past trauma and bullying. The CHR participants were also assessed on a range of psychopathology and functioning.

RESULTS

Individuals at CHR reported significantly more trauma and bullying than healthy controls. Those who had experienced past trauma and bullying were more likely to have increased levels of depression and anxiety and a poorer sense of self.

CONCLUSIONS

These results offer preliminary support for an association between a history of trauma and later subthreshold symptoms.

Life events and psychosis: a review and meta-analysis

INTRODUCTION

Recent models of psychosis implicate stressful events in its etiology. However, while evidence has accumulated for childhood trauma, the role of adult life events has received less attention. Therefore, a review of the existing literature on the relationship between life events and onset of psychotic disorder/experiences is timely.

METHODS

A search was conducted using PsychInfo, Medline, Embase, and Web of Science to identify studies of life events and the onset of psychosis or psychotic experiences within the general population. Given previous methodological concerns, this review included a novel quality assessment tool and focused on findings from the most robust studies. A meta-analysis was performed on a subgroup of 13 studies.

RESULTS

Sixteen studies published between 1968 and 2012 were included. Of these, 14 reported positive associations between exposure to adult life events and subsequent onset of psychotic disorder/experiences. The meta-analysis yielded an overall weighted OR of 3.19 (95% CI 2.15-4.75). However, many studies were limited by small sample sizes and the use of checklist measures of life events, with no consideration of contextual influences on the meaning and interpretation of events.

CONCLUSIONS

Few studies have assessed the role of adult life events in the onset of psychosis. There was some evidence that reported exposure to adult life events was associated with increased risk of psychotic disorder and subclinical psychotic experiences. However, the methodological quality of the majority of studies was low, which urges caution in interpreting the results and points toward a need for more methodologically robust studies.

The impact of child sexual abuse on the course of bipolar disorder: a systematic review

OBJECTIVES

The aim of this review was to elucidate the impact of child sexual abuse on all clinical phenomena that occur after the onset of bipolar disorder, including associated clinical features that are not part of the diagnostic criteria for the disorder.

METHODS

Five databases were searched and supplemented with a hand search of reference lists from retrieved papers. Study quality was assessed using a validated quality assessment tool. Blind assessments of study eligibility and quality were conducted by two independent researchers to reduce bias, minimize errors, and enhance the reliability of findings. Disagreements were resolved by consensus.

RESULTS

Eighteen studies that included a total of 2996 adults and youths with bipolar disorder and met the minimum quality criteria necessary to ensure objectivity and not invalidate results were analyzed. Across studies, child sexual abuse was strongly (and perhaps directly) associated with posttraumatic stress disorder; whereas it was less strongly (and perhaps indirectly) related to suicide attempts, alcohol and/or drug abuse or dependence, psychotic symptoms, and an early age of illness onset. In regard to the association between child sexual abuse and other clinical variables concerning the course of bipolar disorder, evidence was scant or conflicting.

CONCLUSIONS

Child sexual abuse is associated (either directly or indirectly) with some clinical phenomena that represent a more severe form of bipolar disorder. Although such a traumatic experience may directly affect the development of posttraumatic stress disorder, the effects of early sexual abuse on later suicidal behavior, substance abuse, and psychotic symptoms may operate through the mediating influences of certain psychopathological or neurobiological variables.

The association between adult attachment style and delusional-like experiences in a community sample of women

Community-based surveys have found that many otherwise well individuals endorse delusional-like experiences (DLEs). There is extensive literature that describes the demographic and psychosocial correlates of DLE; however, we know little about the association between DLE and attachment style. The association between DLEs (assessed by the Peters Delusional Inventory [PDI]) and interpersonal relationship style (as assessed by the Adult Attachment Questionnaire and the Dyadic Adjustment Scale) was examined in 3360 women. When adjusted for the presence of depressive and anxiety symptoms, high scores on the PDI (lowest versus highest quartiles) were associated with a) difficulties in adult attachment style particularly in the discomfort with closeness and preoccupation with relationships subscales and b) conflictual dyadic adjustment (adjusted odds ratios and 95% confidence intervals, 2.43 and 1.94-3.04, 2.50 and 1.99-3.14, and 2.90 and 1.38-6.06, respectively). The association between adult attachment style and DLE provides new clues into the causal pathway underpinning these common experiences.

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.

Illiteracy and schizophrenia in China: a population-based survey

PURPOSE

Illiterate people may frequently experience social discrimination and exclusion in our modern society. It has been suggested that social adversity increases risk of schizophrenia. The current study examines the relation between illiteracy and schizophrenia.

METHODS

We utilized data on 1,909,205 representative Chinese people of age 18 years or older collected by the Second China National Sample Survey on Disability in 2006 (participation rate 99.8%). Experienced clinical psychiatrists diagnosed schizophrenia among those who were psychiatrically disabled with the ICD-10 symptom checklist.

RESULTS

Strikingly high prevalence of schizophrenia was observed among the young illiterates aged 18-29 years (prevalence 1.64%, 95% confidence interval (CI) 1.35, 1.93) and 30-39 years (prevalence 1.51%, 95% CI 1.34, 1.68), much higher than the prevalence estimates for general Chinese population of similar age reported by any of the previous studies in mainland China. Among people aged less than 40 years, we found that the illiterates were 2.08 times more likely to develop schizophrenia than the literates with no school or primary school education (odds ratio (OR) = 2.08, 95% CI 1.84, 2.36). The association remained statistically significant after adjustment for age, gender, marital status, household income, and location of residence. Consistently, a strong association between illiteracy and schizophrenia (OR = 2.8, 95% CI 1.28, 6.11) was found in conditional logistic regression analysis among matched sibling sets aged less than 40 years that further adjusted for genetic confounding.

CONCLUSION

The risk of schizophrenia may have increased among the socially disadvantaged illiterate people.

Childhood determinants of adult psychiatric disorder

The aim of this project was to assess the current evidence from longitudinal studies for childhood determinants of adult mental illness. Because of the variable and often prolonged period between factors in childhood and the identification of mental illness in adults, prospective studies, particularly birth cohorts, offer the best chance of demonstrating associations in individuals.

A review was undertaken in 2006 of the published literature from longitudinal studies, together with some large-scale retrospective studies and relevant reviews which provided supplementary evidence. The main focus was upon potentially ameliorable characteristics, experiences or situations of childhood; however, other factors, not determinants but pre-cursors, associated with later mental illness could not be left out.

Seven major electronic data-bases of published research were interrogated with a range of key-words and the results supplemented from personal searches, enquiries and reference trails. In excess of 1,500 abstracts were read to select 250 papers for full review. The material was assessed in relation to ten factors:

Psychological disturbance; Genetic Influences; Neurological Deviance; Neuroticism; Behaviour; School Performance; Adversity; Child Abuse or Neglect; Parenting and parent-child relationships; Disrupted and Disfunctional Families.

In 2011 the search was repeated for the period 2006 to mid-2011, using the same search terms and supplemented in the same manner. Over 1,800 abstracts emerged and almost 200 papers selected for more detailed review. These were then integrated into the original text with modifications where necessary. The whole text was then revised and edited in January / February 2012.

There is continuing evidence for the association with later mental ill-health for each of these ten factors, but with different degrees of conviction. The evidence for each is discussed in detail and weighed both separately and in relation to others. These are then summarised, and the research implications are considered. Finally, the implications for prevention are discussed together with the practical potential for preventive and health-promoting programmes.

Blunted cortisol awakening response in men with first episode psychosis: relationship to parental bonding

Early life adversity has been associated with an increased risk for the development of mental health problems, including psychotic disorders, perhaps mediated by a changed regulation of the Hypothalamic Pituitary Adrenal (HPA) axis. Aim of the present study was to confirm our previous finding of an attenuated cortisol awakening response (CAR) in men with first episode psychosis (FEP) and to explore a possible link between a blunted CAR and early adversity as indicated by perceived parental bonding. Fifty-eight patients (38 men, 20 women; mean age 23.25±3.86) with a FEP and 33 healthy community controls (16 men, 17 women; mean age 22.91±3.64) participated in the study. Saliva samples for assessment of the CAR were collected immediately, 30 and 60min after awakening. Complete cortisol samples were available in a reduced sample of 56 patients (37 men) and 30 controls (13 men). Parental bonding during the first 16 years of life was assessed retrospectively with the Parental Bonding Inventory. Results showed a significantly blunted CAR in male compared to female patients, confirming our previously reported findings. We also found a lower CAR in the total FEP group compared to controls, which failed to reach significance after controlling for time of awakening. A significantly lower percentage of patients than controls reported optimal maternal parenting. Within the patient group, significantly fewer male than female patients reported optimal maternal and paternal parenting. Only in patients, unfavorable paternal parenting was related to a blunted CAR. Dysregulation of the HPA axis in male patients might be a consequence of non-optimal parenting and contribute to the less favorable course of psychosis in men compared to women.

Childhood adversity in schizophrenia: a systematic meta-analysis

BACKGROUND

Childhood adversity is a putative risk factor for schizophrenia, although evidence supporting this suggestion is inconsistent and controversial. The aim of this review was to pool and quality assess the current evidence pertaining to childhood adversity in people with schizophrenia compared to other psychiatric disorders and to non-psychiatric controls.

METHOD

Included were case-control, cohort and cross-sectional studies. Medline, EMBASE and PsycINFO databases were searched. Study reporting was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist and pooled evidence quality was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-five studies met inclusion criteria. Moderate to high quality evidence suggests increased rates of childhood adversity in schizophrenia compared to controls [odds ratio (OR) 3.60, p < 0.00001]. Increased childhood adversity was also reported in schizophrenia compared to anxiety disorders (OR 2.54, p = 0.007), although the effect was not significant in the subgroup analysis of five studies assessing only sexual abuse. No differences in rates of childhood adversity were found between schizophrenia and affective psychosis, depression and personality disorders whereas decreased rates of childhood adversity were found in schizophrenia relative to dissociative disorders and post-traumatic stress disorder (OR 0.03, p < 0.0001).

CONCLUSIONS

This is the first meta-analysis to report a medium to large effect of childhood adversity in people with schizophrenia and to assess specificity for schizophrenia. Further research is required that incorporates longitudinal design and other potentially causal variables to assess additive and/or interactive effects.

Childhood trauma and premorbid adjustment among individuals at clinical high risk for psychosis and normal control subjects

AIM

Traumatic childhood experiences are associated with psychotic illness and are frequently reported in patients at clinical high risk (CHR) for psychosis. Moreover, deteriorating premorbid functioning from childhood, and through adolescence, is related to greater severity of overall symptomatology and poorer outcomes in patients with psychosis. We studied the prevalence of traumatic childhood experiences and premorbid adjustment and their association with each other in patients at CHR for psychosis and normal control subjects (NCSs).

METHODS

A total of 20 CHR patients for psychosis and 30 NCSs aged 14 to 35 participated in the present study. The CHR patients were identified as prodromal to psychosis using the Structured Interview for Prodromal Syndromes/Scale of Prodromal Symptoms. Premorbid adjustment was assessed by using the premorbid adjustment scale (PAS), and self-reported childhood trauma was assessed with the Trauma and Distress Scale (TADS).

RESULTS

In CHR patients, TADS and PAS scores were higher than in NCSs. In CHR patients, TADS correlated significantly with the PAS general section and observably, but not significantly, with adolescence and adulthood sections.

CONCLUSION

CHR patients reported more childhood trauma experiences and poorer premorbid adjustment than NCSs. In CHR patients, traumatic childhood experiences are associated with poor general premorbid adjustment.

Sudden death of father or sibling in early childhood increases risk for psychotic disorder

OBJECTIVE

To determine if exposure to a severe, acute stressor during early development is associated with an increased incidence of schizophrenia and bipolar disorder compared to exposure to a chronic stressor.

DESIGN

We identified all those born in Helsinki between 1960 and 1990 whose father or sibling died between their conception and 5-years-of-age through linking two national registers: the Finnish Population Register and the Cause of Death Register. The reason for the death was also extracted from the Cause of Death Register. A third register, the Finnish Hospital Discharge Register, was used to determine psychiatric outcomes in adulthood.

SAMPLE

11,855 individuals whose father or sibling had died before they were 5-years-old. In total, 129 individuals had an ICD 8, 9 or 10 diagnosis of schizophrenia and 165 had a diagnosis of bipolar disorder. 6136 individuals had a father or sibling who died from a sudden, external cause (e.g. accident or suicide) and 5719 individuals had father or sibling who died from a non-external, illness-associated cause.

RESULTS

Sudden loss of a father or sibling led to a significantly greater risk of developing bipolar disorder or schizophrenia in adulthood compared to loss of a father or sibling from illness. These associations are independent of sex, parental history of psychiatric illness, age at exposure to loss and age at follow-up.

CONCLUSION

Our findings are in keeping with accumulating evidence which indicates that exposure to stress during early development can increase the risk of psychotic illness among those exposed.

Comparison of first-episode and chronic patients diagnosed with schizophrenia: symptoms and childhood trauma

AIM

There has been considerable interest in identifying and addressing the specific needs of early-episode patients diagnosed with schizophrenia in the hope that by addressing such needs early, chronic disabilities can be avoided.

METHODS

One hundred twenty-eight early-episode and 571 chronic patients were compared on socio-demographic characteristics, clinical symptoms and history of childhood trauma. Symptoms were measured with the Positive and Negative Syndrome Scale (PANSS), and trauma with the short version of the Childhood Trauma Questionnaire.

RESULTS

First-episode patients scored 9.3% higher than chronic patients on the PANSS positive symptom scale and 16.3% lower on the negative symptom scale. More first episode patients reported childhood sexual abuse (P = 0.033); however, fewer reported childhood emotional neglect (P = 0.01). Childhood trauma was associated with positive symptoms, specifically with hallucinations in first-episode patients (r = 0.174; P = 0.049). Moreover, fewer parents of first episode patients were living alone (P = 0.008). On multiple logistic regression, the first-episode patients were younger (odds ratio = 0.92), had higher PANSS positive symptom scores (odds ratio 1.04) and lower negative symptom scores (odds ratio 0.948 recalculate).

CONCLUSIONS

More positive symptoms, fewer negative symptoms, less isolated parents and greater risk of childhood sexual abuse might warrant attention in first episode schizophrenia and perhaps should be a focus for the development of targeted interventions.

High prevalence of childhood trauma in patients with schizophrenia spectrum and affective disorder

OBJECTIVE

Childhood trauma (CT) is a major risk factor for various psychiatric disorders. We wanted to determine the prevalence of CT in a catchment area-based sample of schizophrenia spectrum and affective disorder (including bipolar disorder and depressive episodes with psychotic features) and to explore potential differences in types of CT between the diagnostic groups.

METHOD

Three hundred five patients were recruited consecutively from psychiatric units at 3 major hospitals in Oslo, Norway, diagnosed with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Traumatic childhood events were assessed with Childhood Trauma Questionnaire.

RESULTS

Eighty-two percent of the patients had experienced one or more CT events, the most frequent subtype of trauma being emotional neglect. The schizophrenia spectrum group reported significantly more physical abuse and physical neglect than the affective group.

CONCLUSION

A high prevalence of CT in patients with severe mental disorder was detected. This reminds us of the importance of exploring this issue when we treat such patients. The mechanisms behind these differences are unclear. Further research is needed to study potential associations between CT and the clinical picture of the disorder.

Child loss and psychosis onset: evidence for traumatic experience as an etiological factor in psychosis

Previous research suggests that trauma may contribute to psychosis onset. In this study, we examine the effect of parental loss of a child on the onset of psychotic experience using data from the National Comorbidity Survey Replication, hypothesizing that child loss will precede the onset of psychosis and will be associated with a later age of onset. We likewise tested this association for six other psychiatric conditions to demonstrate specificity for psychosis. Individuals with a psychotic disorder who had lost a child had a significantly later age of onset, particularly in males, even when controlling for demographic variables and co-occurring substance abuse and psychiatric disorders. Psychosis onset frequently occurred within a year of child loss. No associations were found between child loss and onset of other psychiatric conditions, supporting specificity of the effect on psychosis. The presented findings implicate child loss as an etiological factor in the onset of psychosis, providing converging evidence with previous studies demonstrating associations between more widely studied trauma exposures (abuse, neglect, and assault) and psychosis.

Trauma profile in Egyptian adolescents with first-episode schizophrenia: relation to psychopathology and plasma brain-derived neurotrophic factor

We aimed to investigate the relation of trauma profile to schizophrenia psychopathology in a sample of Egyptian drug-naïve adolescent patients with first-episode schizophrenia. In addition, a hypothesized mediating effect of brain-derived neurotrophic factor (BDNF) in this relation was formally tested. We assessed 74 eligible outpatients using the Positive and Negative Syndrome Scale (PANSS) for measuring psychopathology. Trauma histories were recorded with the help of the Cumulative Trauma Measure. Serum BDNF levels were estimated by enzyme-linked immunosorbent assay. Total cumulative trauma, personal identity trauma, and survival trauma were found to be the significant predictors for schizophrenia psychopathology. BDNF fully mediated the associations between total cumulative trauma and overall schizophrenia psychopathology. BDNF also mediated the associations between some types of trauma and both PANSS-positive and PANSS-negative symptom factors. We concluded that total cumulative trauma and certain trauma types are linked with schizophrenia psychopathology. BDNF appears to mediate these links.

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.

Estudos traducionais de neuropsiquiatria e esquizofrenia: modelos animais genéticos e de neurodesenvolvimento

Sintomas psiquiátricos são subjetivos por natureza e tendem a se sobrepor entre diferentes desordens. Sendo assim, a criação de modelos de uma desordem neuropsiquiátrica encontra desafios pela falta de conhecimento dos fundamentos da fisiopatologia e diagnósticos precisos. Modelos animais são usados para testar hipóteses de etiologia e para representar a condição humana tão próximo quanto possível para aumentar nosso entendimento da doença e avaliar novos alvos para a descoberta de drogas. Nesta revisão, modelos animais genéticos e de neurodesenvolvimento de esquizofrenia são discutidos com respeito a achados comportamentais e neurofisiológicos e sua associação com a condição clínica. Somente modelos animais específicos de esquizofrenia podem, em último caso, levar a novas abordagens diagnósticas e descoberta de drogas. Argumentamos que biomarcadores moleculares são importantes para aumentar a tradução de animais a humanos, já que faltam a especificidade e a fidelidade necessárias às leituras comportamentais para avaliar sintomas psiquiátricos humanos.

Neurodevelopmental model of schizophrenia: update 2012

The neurodevelopmental model of schizophrenia, which posits that the illness is the end state of abnormal neurodevelopmental processes that started years before the illness onset, is widely accepted, and has long been dominant for childhood-onset neuropsychiatric disorders. This selective review updates our 2005 review of recent studies that have impacted, or have the greatest potential to modify or extend, the neurodevelopmental model of schizophrenia. Longitudinal whole-population studies support a dimensional, rather than categorical, concept of psychosis. New studies suggest that placental pathology could be a key measure in future prenatal high-risk studies. Both common and rare genetic variants have proved surprisingly diagnostically nonspecific, and copy number variants (CNVs) associated with schizophrenia are often also associated with autism, epilepsy and intellectual deficiency. Large post-mortem gene expression studies and prospective developmental multi-modal brain imaging studies are providing critical data for future clinical and high-risk developmental brain studies. Whether there can be greater molecular specificity for phenotypic characterization is a subject of current intense study and debate, as is the possibility of neuronal phenotyping using human pluripotent-inducible stem cells. Biological nonspecificity, such as in timing or nature of early brain development, carries the possibility of new targets for broad preventive treatments.

Childhood bullying and the association with psychosis in non-clinical and clinical samples: a review and meta-analysis

BACKGROUND

Approximately 11% of schoolchildren are bullied on a regular basis. It has been argued that continuous exposure to stress is related to the development of psychotic symptoms. The current study sought to investigate whether being bullied in childhood is related to the development of psychotic symptoms.

METHOD

A search of PubMed, PsycINFO and EMBASE was conducted. The reference lists of included papers were searched to identify other eligible papers. A meta-analysis was performed on a subgroup of studies.

RESULTS

We found four clinical and 10 general population studies that met inclusion criteria. The results of the clinical studies were mixed. However, the results of the non-clinical studies provided more consistent evidence that school bullying is related to the development of non-clinical psychotic symptoms. Stronger associations were found with increased frequency and severity and longer duration of being bullied. We performed a meta-analysis on seven population-based studies, yielding unadjusted and adjusted odds ratios (ORs) of 2.7 [95% confidence interval (CI) 2.1-3.6] and 2.3 (95% CI 1.5-3.4) respectively.

CONCLUSIONS

Although there is some evidence of an association between bullying and psychosis in clinical samples, the research is too sparse to draw any firm conclusions. However, population-based non-clinical studies support the role of bullying in the development of psychotic symptoms later in life. These findings are consistent with findings of an increased risk of psychotic symptoms among those exposed to other types of abuse.

[Environmental risk factors for schizophrenia: a review]

BACKGROUND

Evidence of variations in schizophrenia incidence rates has been found in genetically homogenous populations, depending on changes within time or space of certain environmental characteristics. The consideration of the impact of environmental risk factors in etiopathogenic studies has put the environment in the forefront of research regarding psychotic illnesses. Various environmental factors such as urbanicity, migration, cannabis, childhood traumas, infectious agents, obstetrical complications and psychosocial factors have been associated with the risk of developing schizophrenia. These risk factors can be biological, physical, psychological as well as social and may operate at different times in an individual's life (fetal period, childhood, adolescence and early adulthood). Whilst some of these factors act on an individual level, others act on a populational level, modulating the individual risk. These factors can have a direct action on the development of schizophrenia, or on the other hand act as markers for directly implicated factors that have not yet been identified.

LITERATURE FINDINGS

This article summarizes the current knowledge on this subject. An extensive literature search was conducted via the search engine Pubmed. Eight risk factors were selected and developed in the following paper: urbanicity (or living in an urban area), cannabis, migration (and ethnic density), obstetrical complications, seasonality of birth, infectious agents (and inflammatory responses), socio-demographic factors and childhood traumas. For each of these factors, we provide information on the importance of the risk, the vulnerability period, hypotheses made on the possible mechanisms behind the factors and the level of proof the current research offers (good, medium, or insufficient) according to the amount, type, quality and concordance of the studies at hand. Some factors, such as cannabis, are "unique" in their influence on the development of schizophrenia since it labels only one risk factor. Others, such as obstetrical complications, are grouped (or "composed") in that they include various sub-factors that can influence the development of schizophrenia.

DISCUSSION

The data reviewed clearly demonstrates that environmental factors have an influence on the risk of developing schizophrenia. For certain factors - cannabis, migration, urbanicity, obstetrical complications, seasonality - there is enough evidence to establish an association with the risk of schizophrenia. This association, however, remains weak (especially for seasonality). With the exception of cannabis, no direct link can yet be established. Concerning the three remaining factors - childhood traumas, infectious agents, socio-demographic factors - the available proof is insufficient. One main limitation concerning all environmental factors is the generalization of results due to the fact that the studies were conducted on geographically limited populations. The current state of knowledge does not allow us to determine the mechanisms by which these factors may act.

CONCLUSION

Further research is needed to fill the gaps in our understanding of the subject. In response to this need, a collaborative European project (European Study of Gene-Environment Interactions [EU GEI]) was set-up. This study proposes the analysis of those environmental factors that influence the incidence of schizophrenia in various European countries, in both rural and urban settings, migrant and native populations, as well as their interaction with genetic factors.

First-episode psychosis at the West Bologna Community Mental Health Centre: results of an 8-year prospective study

BACKGROUND

Research mostly conducted in the UK and northern Europe has established that there are high rates of first-episode psychosis (FEP) in large cities and immigrant populations; moreover, psychosis has been found to be associated with cannabis use and early trauma. The present study aimed to evaluate the incidence rate of FEP and the distribution of several risk factors (e.g. age, ethnicity, substance abuse) in Bologna, Italy.

METHOD

The Bologna FEP (BoFEP) study is an 8-year prospective study. All FEP patients, 18-64 years old, consecutively referred to the West Bologna Community Mental Health Centre (CMHC) from 2002 to 2009 were evaluated. Sociodemographic information, migration history and clinical data were collected through an ad-hoc schedule. Psychiatric diagnoses were recorded using the Schedule for Clinical Assessment of Neuropsychiatry (SCAN).

RESULTS

The overall incidence rate (IR) in the BoFEP study was 16.4 per 100 000 person-years [95% confidence interval (CI) 13.9-18.9]. The incidence was higher in young people, men and migrants (MI).

CONCLUSIONS

The IR of FEP found by the Bologna study is lower than that found by other European studies. However, as in other studies, the incidence was higher in certain groups. This heterogeneity has implications for policy and mental health service development, and for understanding the aetiology of psychosis.

Childhood trauma and hippocampal and amygdalar volumes in first-episode psychosis

OBJECTIVE

A history of childhood trauma is common in individuals who later develop psychosis. Similar neuroanatomical abnormalities are observed in people who have been exposed to childhood trauma and people with psychosis. However, the relationship between childhood trauma and such abnormalities in psychosis has not been investigated. This study aimed to explore the association between the experience of childhood trauma and hippocampal and amygdalar volumes in a first-episode psychosis (FEP) population.

METHODS

The study employed an observational retrospective design. Twenty-one individuals, who had previously undergone magnetic resonance imaging procedures as part of the longitudinal Northern Ireland First-Episode Psychosis Study, completed measures assessing traumatic experiences and were included in the analysis. Data were subject to correlation analyses (r and r (pb)). Potential confounding variables (age at FEP and delay to scan from recruitment) were selected a priori for inclusion in multiple regression analyses.

RESULTS

There was a high prevalence of lifetime (95%) and childhood (76%) trauma in the sample. The experience of childhood trauma was a significant predictor of left hippocampal volume, although age at FEP also significantly contributed to this model. There was no significant association between predictor variables and right hippocampal volume. The experience of childhood trauma was a significant predictor of right and total amygdalar volumes and the hippocampal/amygdalar complex volume as a whole.

CONCLUSIONS

The findings indicate that childhood trauma is associated with neuroanatomical measures in FEP. Future research controlling for childhood traumatic experiences may contribute to explaining brain morphology in people with psychosis.

[Trauma and psychosis--part 1. On the association of early childhood maltreatment in clinical populations with psychotic disorders]

A comprehensive literature stresses a high percentage of severe childhood maltreatment in the history of many psychotically ill patients treated in mental health services. Early childhood abuse seems to be associated among other things with a more severe clinical state, a more chronic course of illness and a more unfavourable psychosocial adaptation. In order not to jump to unwarranted causal conclusions, several conceptual und methodological problems have to be clarified before. From a conceptual perspective psychotic disorders diagnosed according to conventional criteria define only a minor subgroup within a much broader psychosis continuum in general population. Early childhood abuse has to be differentiated according to type, severity, timing, and context. The rates of early childhood abuse are high in general population. The methods of measurement of psychotic symptoms on the one side, of early trauma on the other side have to be critically evaluated. There is an empirically well founded association of childhood maltreatment and psychological and psychosomatic morbidity during adult years in general. In order to establish a potential conditional link also to psychotic disorders, clinical populations have to be compared to adequate control groups at least. A systematic literature search shows a very small number of studies including control groups at all. These studies underline that early childhood abuse may be significantly associated to the risk of psychosis indeed. The conditional role of early childhood abuse, however, has to be investigated only within a multifactorial biopsychosocial model of psychotic illness.

Schizophrenia patients with a history of childhood trauma have a pro-inflammatory phenotype

BACKGROUND

Increasing evidence indicates that childhood trauma is a risk factor for schizophrenia and patients with this syndrome have a pro-inflammatory phenotype. We tested the hypothesis that the pro-inflammatory phenotype in schizophrenia is associated with childhood trauma and that patients without a history of such trauma have a similar immune profile to healthy controls.

METHOD

We recruited 40 schizophrenia patients and 40 controls, all of whom completed the Childhood Trauma Questionnaire (CTQ). Using enzyme-linked immunosorbent assay (ELISA) techniques, we measured peripheral levels of interleukin (IL)-1β, IL-6, IL-8 and tumour necrosis factor (TNF)-α. These immune parameters were compared in schizophrenia with childhood trauma, schizophrenia without childhood trauma and healthy controls.

RESULTS

Patients with childhood trauma had higher levels of IL-6 and TNF-α than patients without trauma and healthy controls, and TNF-α levels correlated with the extent of the trauma. Patients with no trauma had similar immune profiles to controls.

CONCLUSIONS

Childhood trauma drives changes, possibly epigenetic, that generate a pro-inflammatory phenotype.

Predicting risk and the emergence of schizophrenia

This article gives an overview of genetic and environmental risk factors for schizophrenia. The presence of certain molecular, biological, and psychosocial factors at certain points in the life span, has been linked to later development of schizophrenia. All need to be considered in the context of schizophrenia as a lifelong brain disorder. Research interest in schizophrenia is shifting to late childhood/early adolescence for screening and preventative measures. This article discusses those environmental risk factors for schizophrenia for which there is the largest evidence base.

Etiopathogenic perspectives on chronic psycho traumatic and chronic psychotic symptoms: the hypothesis of a hyperdopaminergic endophenotype of PTSD

Post traumatic stress disorder (PTSD) is a complex and heterogeneous disorder, which specific symptoms are re-experiencing, increased arousal and avoidance of stimuli associated with the trauma. PTSD has much comorbidity like depression, substance abuse, somatic complaints, repeated dissociative phenomena and transitory or chronic psychotic reactions. PTSD can manifest itself in different clinical forms: some patients present higher symptoms in one domain as compared to another, probably because of abnormalities in different neurobiological systems. Hyposerotonergic and hypernoradrenergic PTSD endophenotypes have been previously identified and the purpose of this paper is to focus on the hypothesis of a hyperdopaminergic endophenotype. The current review discusses several entities: PTSD with psychotic features with or without depression, the comorbide use of psychoactive substances that increase psychotic symptoms and traumatic brain injuries as agents of psycho traumatic and psychotic features. For all of these nosographic entities, the dopaminergic neuromodulation may play a central role. The hypothesis of a hyperdopaminergic endophenotype of PTSD opens up new research and therapeutic perspectives. Although antipsychotics are frequently used for people with PTSD further studies are needed to develop a consensus on the guidelines for treating the psychotic forms of PTSD.

Maternal deprivation effects on brain plasticity and recognition memory in adolescent male and female rats

Data from both human and animal studies suggest that exposure to stressful life events at neonatal stages may increase the risk of psychopathology at adulthood. In particular, early maternal deprivation, 24 h at postnatal day (pnd) 9, has been associated with persistent neurobehavioural changes similar to those present in developmental psychopathologies such as depression and schizophrenic-related disorders. Most neuropsychiatric disorders first appear during adolescence, however, the effects of MD on adolescent animals' brain and behaviour have been scarcely explored. In the present study, we aimed to investigate the emotional and cognitive consequences of MD in adolescent male and female rats, as well as possible underlying neurobiological mechanisms within frontal cortex and hippocampus. Animals were exposed to a battery of behavioural tasks, from pnd 35 to 42, to evaluate cognitive [spontaneous alternation task (SAT) and novel object test (NOT)] and anxiety-related responses [elevated plus maze (EPM)] during adolescence. Changes in neuronal and glial cells, alterations in synaptic plasticity as well as modifications in cannabinoid receptor expression were investigated in a parallel group of control and adolescent (pnd 40) male and female animals. Notably, MD induced a significant impairment in recognition memory exclusively among females. A generalized decrease in NeuN expression was found in MD animals, together with an increase in hippocampal glial fibrillar acidic protein (GFAP) expression exclusively among MD adolescent males. In addition, MD induced in the frontal cortex and hippocampus of male and female adolescent rats a significant reduction in brain derived neurotrophic factor (BDNF) and postsynaptic density (PSD95) levels, together with a decrease in synaptophysin in frontal cortex and neural cell adhesion molecule (NCAM) in hippocampus. MD induced, in animals of both sexes, a significant reduction in CB1R expression, but an increase in CB2R that was statistically significant only for the frontal cortex. Taken together, these results indicate that adolescent females are more vulnerable than males to the cognitive deficits derived from MD despite the changes in neural cells, cannabinoid receptors, as well as the reduction in neural plasticity seem to be similar in both sexes. Further investigation is needed to understand the neurobiological mechanisms underlying the sexual dimorphisms associated to the MD effects, and thus, for a better understanding of the specific sex-dependent vulnerabilities to early life stress. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.

Advanced paternal age increases the risk of schizophrenia and obsessive-compulsive disorder in a Chinese Han population

Using the Structured Clinical Interview for DSM-IV, patient and non-patient version (SCID-P/NP), this study investigated 351 patients with schizophrenia, 122 with obsessive-compulsive disorder (OCD), and 238 unrelated healthy volunteers in a Chinese Han population. The relative risks posed by advanced paternal age for schizophrenia and OCD in offspring were computed under logistic regression analyses and adjusted for the participant's sex, age and co-parent age at birth. Compared to the offspring with paternal age of 25-29 years old, the relative risks rose from 2.660 to 10.183 in the paternal age range of 30-34 and ≥35. The relative risks for OCD increased from 2.225 to 5.413 in 30-34 and ≥35. For offspring with paternal age of <25, the odds ratios of developing schizophrenia and OCD were 0.628 and 0.289 respectively, whereas an association between increased maternal age and risk for schizophrenia/OCD was not seen. Interaction analysis showed an interaction effect between paternal age and maternal age at birth. Such a tendency of risk affected by parental age for schizophrenia and OCD existed after splitting out the data of early onset patients. Sex-specific analyses found that the relative risks for schizophrenia with paternal age of 30-34 and ≥35 in male offspring were 2.407 and 10.893, and in female offspring were 3.080 and 9.659. The relative risks for OCD with paternal age of 30-34 and ≥35 in male offspring were 3.493 and 7.373, and in female offspring 2.005 and 4.404. The mean paternal age of schizophrenia/OCD patients born before the early 1980s was much greater than that of patients who were born after then. The findings illustrated that advanced paternal age is associated with increased risk for both schizophrenia and OCD in a Chinese Han population, prominently when paternal age is over 35. Biological and non-biological mechanisms may both be involved in the effects of advanced paternal age on schizophrenia and OCD.

Schizophrenia shows a unique metabolomics signature in plasma

Schizophrenia is a severe complex mental disorder affecting 0.5-1% of the world population. To date, diagnosis of the disease is mainly based on personal and thus subjective interviews. The underlying molecular mechanism of schizophrenia is poorly understood. Using targeted metabolomics we quantified and compared 103 metabolites in plasma samples from 216 healthy controls and 265 schizophrenic patients, including 52 cases that do not take antipsychotic medication. Compared with healthy controls, levels of five metabolites were found significantly altered in schizophrenic patients (P-values ranged from 2.9 × 10(-8) to 2.5 × 10(-4)) and in neuroleptics-free probands (P-values ranging between 0.006 and 0.03), respectively. These metabolites include four amino acids (arginine, glutamine, histidine and ornithine) and one lipid (PC ae C38:6) and are suggested as candidate biomarkers for schizophrenia. To explore the genetic susceptibility on the associated metabolic pathways, we constructed a molecular network connecting these five aberrant metabolites with 13 schizophrenia risk genes. Our result implicated aberrations in biosynthetic pathways linked to glutamine and arginine metabolism and associated signaling pathways as genetic risk factors, which may contribute to patho-mechanisms and memory deficits associated with schizophrenia. This study illustrated that the metabolic deviations detected in plasma may serve as potential biomarkers to aid diagnosis of schizophrenia.

Maternal separation is associated with strain-specific responses to stress and epigenetic alterations to Nr3c1, Avp, and Nr4a1 in mouse

Stressful events early in life have been widely linked to behavioral phenotypes and have been implicated in the development of psychiatric disorders. Using a maternal separation paradigm, we investigated phenotypic and epigenetic changes following early life stress in two inbred strains of mice, C57BL/6J and DBA/2J. We found an increase in the corticosterone response to stress in male, C57BL/6J mice that had undergone maternal separation compared to controls. In addition, early life stress induced a number of mild but significant behavioral changes, many of which were sex and strain dependent. Following maternal separation anxiety was decreased in males but increased in DBA/2J females, DBA/2J males displayed reduced exploration of a novel object, and baseline activity was altered in males of both strains. Finally, we examined DNA methylation levels in the hippocampus across promoter regions of Nr3c1, Avp, and Nr4a1, and found altered levels at several CpG sites in maternally separated male mice compared to controls. This study contributes to a growing body of recent literature suggesting that epigenetic changes may mediate the impact of early life stress on behavior. In particular, we establish that the phenotypic and epigenetic responses to an adverse environment differ as a function of genetic background.

Childhood adversities increase the risk of psychosis: a meta-analysis of patient-control, prospective- and cross-sectional cohort studies

Evidence suggests that adverse experiences in childhood are associated with psychosis. To examine the association between childhood adversity and trauma (sexual abuse, physical abuse, emotional/psychological abuse, neglect, parental death, and bullying) and psychosis outcome, MEDLINE, EMBASE, PsychINFO, and Web of Science were searched from January 1980 through November 2011. We included prospective cohort studies, large-scale cross-sectional studies investigating the association between childhood adversity and psychotic symptoms or illness, case-control studies comparing the prevalence of adverse events between psychotic patients and controls using dichotomous or continuous measures, and case-control studies comparing the prevalence of psychotic symptoms between exposed and nonexposed subjects using dichotomous or continuous measures of adversity and psychosis. The analysis included 18 case-control studies (n = 2048 psychotic patients and 1856 nonpsychiatric controls), 10 prospective and quasi-prospective studies (n = 41,803) and 8 population-based cross-sectional studies (n = 35,546). There were significant associations between adversity and psychosis across all research designs, with an overall effect of OR = 2.78 (95% CI = 2.34-3.31). The integration of the case-control studies indicated that patients with psychosis were 2.72 times more likely to have been exposed to childhood adversity than controls (95% CI = 1.90-3.88). The association between childhood adversity and psychosis was also significant in population-based cross-sectional studies (OR = 2.99 [95% CI = 2.12-4.20]) as well as in prospective and quasi-prospective studies (OR = 2.75 [95% CI = 2.17-3.47]). The estimated population attributable risk was 33% (16%-47%). These findings indicate that childhood adversity is strongly associated with increased risk for psychosis.

Do child abuse and maltreatment increase risk of schizophrenia?

INTRODUCTION

Although childhood abuse is a recognised risk factor for depression, post-traumatic stress disorder, and substance misuse, its role in the aetiology of psychotic disorder remained controversial. This is in part because the putative effect of childhood trauma on psychosis has been mostly evaluated by small, cross sectional, uncontrolled studies that raised methodological issues.

METHODS

Papers concerning the association between childhood trauma and psychotic disorders (to November, 2011) were identified using a comprehensive search of PubMed, Psychinfo, and Scopus and analysing reference list of relevant papers. A narrative synthesis was used to summarise results.

RESULTS

An association between childhood abuse and psychotic symptoms was consistently reported by large cross sectional surveys with an effect ranging from 1.7 to 15. However, we cannot conclude that the relationship is causal as lack of longitudinal studies prevent us from fully excluding alternative explanations such as reverse causality. Gender, cannabis use, and depressive and post-traumatic stress disorder symptoms appear to moderate the effect of childhood trauma on psychotic disorders. However, specificity of childhood abuse in psychotic disorders and, particularly, in schizophrenia has not been demonstrated.

CONCLUSION

Although the association between childhood abuse and psychosis has been replicated, the etiological role of such early adversity has yet to be fully clarified. So far none of the studies reported support the hypothesis that childhood abuse is either sufficient or necessary to develop a psychotic disorder. It seems likely that any effect of childhood abuse on schizophrenia needs to be understood in terms of genetic susceptibility and interaction with other environmental risk factors.

Social defeat interacts with Disc1 mutations in the mouse to affect behavior

DISC1 (Disrupted-in-schizophrenia 1) is a strong candidate susceptibility gene for psychiatric disease that was originally discovered in a family with a chromosomal translocation severing this gene. Although the family members with the translocation had an identical genetic mutation, their clinical diagnosis and presentation varied significantly. Gene-environment interactions have been proposed as a mechanism underlying the complex heritability and variable phenotype of psychiatric disorders such as major depressive disorder and schizophrenia. We hypothesized that gene-environment interactions would affect behavior in a mutant Disc1 mouse model. We examined the effect of chronic social defeat (CSD) as an environmental stressor in two lines of mice carrying different Disc1 point mutations, on behaviors relevant to psychiatric illness: locomotion in a novel open field (OF), pre-pulse inhibition (PPI) of the acoustic startle response, latent inhibition (LI), elevated plus maze (EPM), forced swim test (FST), sucrose consumption (SC), and the social interaction task for sociability and social novelty (SSN). We found that Disc1-L100P +/- and wild-type mice have similar anxiety responses to CSD, while Q31L +/- mice had a very different response. We also found evidence of significant gene-environment interactions in the OF, EPM and SSN.

Early environmental exposures influence schizophrenia expression even in the presence of strong genetic predisposition

There are few studies of environmental factors in familial forms of schizophrenia. We investigated whether childhood adversity or environmental factors were associated with schizophrenia in a familial sample where schizophrenia is associated with the NOSA1P gene. We found that a cumulative adversity index including childhood illness, family instability and cannabis use was significantly associated with narrow schizophrenia, independent of NOSA1P risk genotype, previously measured childhood trauma, covariates and familial clustering (adjusted odds ratio (95% confidence interval)=1.55 (1.01, 2.38)). The results provide further support that early environmental exposures influence schizophrenia expression even in the presence of strong genetic predisposition.