Maternal recall bias, obstetric history and schizophrenia

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.

Gender differences in the association between environment and psychosis

Various environmental exposures have been associated with psychosis spectrum disorder. However, the role of gender in this association has received little attention. Therefore, we conducted a systematic review to evaluate gender-related differences and identified 47 research articles investigating the associations of psychosis with childhood adversity, substance use, urbanicity, migration, season of birth, and obstetric complication in the PubMed database. The findings suggest that childhood abuse may be more strongly associated with a risk to develop psychosis and an earlier age at onset of illness in women than in men. Furthermore, childhood adversity has been associated with the severity of different symptom dimensions in men and women. Growing up in an urban environment and immigration are more strongly associated with psychosis risk in men than in women. Despite a higher prevalence of substance abuse comorbidity in men diagnosed with psychotic disorders, it appears that the association between substance use and psychosis risk may be stronger in women. These findings should be evaluated with caution considering several methodological limitations, limited number of studies, and lack of consistency across results. Overall, although further investigation is needed, our review shows that gender-related differences in the associations of environmental exposures with psychosis expression may exist.

Obstetric complications in patients with schizophrenia and their unaffected siblings

Objective

We sought to explore whether obstetric complications (OCs) are more likely to occur in the presence of familial/genetic susceptibility for schizophrenia or whether they themselves represent an independent environmental risk factor for schizophrenia.

Methods

The presence of OCs was assessed through maternal interview on 216 subjects, comprising 36 patients with schizophrenia from multiply affected families, 38 of their unaffected siblings, 31 schizophrenic patients with no family history of psychosis, 51 of their unaffected siblings and 60 normal comparison subjects. We examined the familiality of OCs and whether OCs were commoner in the patient and sibling groups than in the control group.

Results

OCs tended to cluster within families, especially in multiply affected families. Patients with schizophrenia, especially those from multiply affected families, had a significantly higher rate of OCs compared to normal comparison subjects, but there was no evidence for an elevated rate of OCs in unaffected siblings.

Conclusion

Our data provides little evidence for a link between OCs and genetic susceptibility to schizophrenia. If high rates of OCs are related to schizophrenia genes, this relationship is weak and will only be detected by very large sample sizes.

Perinatal complications and executive dysfunction in early-onset schizophrenia

BACKGROUND

The present study examined the association between perinatal obstetric complications and executive dysfunction in early-onset schizophrenia (EOS), compared to healthy controls. Higher incidences of obstetric complications and more severe executive dysfunctions characterize EOS. Research shows extensive brain maturation in newborns, suggesting them to be particularly vulnerable for perinatal insults. Executive function is mainly mediated by the prefrontal cortex, an area that matures last during pregnancy. Thus, exposure to perinatal complications may influence executive dysfunction in EOS.

METHODS

The participants were 19 EOS patients and 54 healthy controls. Executive function was assessed with the D-KEFS Color Word Interference Test and the Wisconsin Card Sorting Test. Information on perinatal obstetric complications and Apgar 5-min scores were obtained from the Norwegian Medical Birth Registry. Associations between perinatal conditions and executive function were studied using stepwise regression analyses.

RESULTS

Perinatal complications, and especially shorter gestational lengths, were significantly associated with significant executive dysfunctions in EOS. Perinatal complications did not affect executive function among healthy controls. A significant relationship between lower Apgar 5-min scores and executive dysfunction was found among both EOS patients and healthy controls.

CONCLUSIONS

Exposure to perinatal complications, and particularly a shorter gestational length, was associated with increased executive dysfunction in EOS. Exposed healthy controls did not exhibit similar executive difficulties, suggesting that the EOS patients seemed especially vulnerable for executive deficits due to perinatal insults. The findings indicate that EOS youths learn more slowly and experience more difficulty with problem-solving, which carry important implications for clinical practice. Lower Apgar 5-min scores were associated with executive dysfunction in both groups. Low Apgar score at 5 min may therefore be an important early indicator of executive difficulties among adolescents, independent of diagnosis.

Maternal stress, prenatal medical illnesses and obstetric complications: Risk factors for schizophrenia spectrum disorder, bipolar disorder and major depressive disorder

Maternal stress and medical illnesses during early life are well-documented environmental indicators of an increased risk of schizophrenia. Few studies, conversely, have confirmed an association with major affective disorders. The present study examined the impact of maternal stress, medical illnesses and obstetric complications on the development of severe mental disorder in 240 patients with a diagnosis of schizophrenia spectrum disorder, bipolar disorder, or major depressive disorder and matched with 85 controls. Mothers of participants were asked about stressful events during pregnancy using the Social Readjustment Scale; information on prenatal/perinatal illnesses were acquired from medical records. Schizophrenia spectrum disorder was positively associated with maternal stress (OR = 2.16), infections (OR = 7.67), inadequate weight gain (OR = 9.52) during pregnancy, and peripartum asphyxia (OR = 4.00). An increased risk of bipolar disorder was associated with head circumference < 32 cm at birth (OR = 5.40) and inversely with inadequate weight gain (OR = 0.29). Major depressive disorder diagnosis was inversely related to inadequate weight gain (OR = 0.22). These results support a role for maternal stress, medical illnesses and obstetric complications as risk factors for subsequent severe mental illness in adulthood. Further research is needed, especially with regard to affective disorders.

Gestational length affects neurocognition in early-onset schizophrenia

Obstetric complications (OC) have been linked to an increased risk for schizophrenia in offspring, especially in early-onset schizophrenia (EOS). Extensive cognitive deficits occur in EOS, although no study has yet to investigate the relationship between OC and cognition in EOS. This study aims to examine the frequency of OC in EOS compared to controls, and also investigates the relationship between OC and neurocognitive dysfunction in the two groups. Nineteen EOS patients and 53 healthy controls were tested with the MATRICS Consensus Cognitive Battery (MCCB), and the cognitive measures were combined with OC data from the Norwegian Birth Registry. The results indicated no group differences in OC in EOS and healthy controls, but a shorter gestational length in the EOS group led to significant decreases in the overall neurocognitive composite score, and in processing speed. This suggests that the poorer neuropsychological performances commonly found in EOS may be partly attributable to the length of gestation. The worsened neurocognitive functioning did not appear among controls, so gestational length had a different impact on the two groups. Our findings indicated that a shorter gestational length did not increase the risk for developing EOS, but did significantly affect the cognitive difficulties in this group.

BDNF rs6265 methylation and genotype interact on risk for schizophrenia

Epigenetic mechanisms can mediate gene-environment interactions relevant for complex disorders. The BDNF gene is crucial for development and brain plasticity, is sensitive to environmental stressors, such as hypoxia, and harbors the functional SNP rs6265 (Val(66)Met), which creates or abolishes a CpG dinucleotide for DNA methylation. We found that methylation at the BDNF rs6265 Val allele in peripheral blood of healthy subjects is associated with hypoxia-related early life events (hOCs) and intermediate phenotypes for schizophrenia in a distinctive manner, depending on rs6265 genotype: in ValVal individuals increased methylation is associated with exposure to hOCs and impaired working memory (WM) accuracy, while the opposite is true for ValMet subjects. Also, rs6265 methylation and hOCs interact in modulating WM-related prefrontal activity, another intermediate phenotype for schizophrenia, with an analogous opposite direction in the 2 genotypes. Consistently, rs6265 methylation has a different association with schizophrenia risk in ValVals and ValMets. The relationships of methylation with BDNF levels and of genotype with BHLHB2 binding likely contribute to these opposite effects of methylation. We conclude that BDNF rs6265 methylation interacts with genotype to bridge early environmental exposures to adult phenotypes, relevant for schizophrenia. The study of epigenetic changes in regions containing genetic variation relevant for human diseases may have beneficial implications for the understanding of how genes are actually translated into phenotypes.

Fluctuating dermatoglyphic asymmetries in youth at ultrahigh-risk for psychotic disorders

Fluctuating dermatoglyphic asymmetry represents one specific class of minor physical anomaly that has been proposed to reflect prenatal insult and vulnerability to psychosis. However, very little is known about fluctuating dermatoglyphic asymmetry in youth showing symptoms of ultrahigh risk (UHR) for psychosis. Using high-resolution photographs of fingerprints and clinical interviews, the UHR group in this study showed greater fluctuating dermatoglyphic asymmetry compared to controls; however, this was not further linked to symptomatology. The results of this study provide an important perspective on potential biomarkers and support neurodevelopmental conceptions of psychosis.

The epidemiology of multiple sclerosis: insights to a causal cascade

MS-pathogenesis involves both genetic-susceptibility and environmental determinants. Three (or more) sequential environmental-factors are implicated. The first acts near birth, the second acts during childhood/adolescence, and the third acts subsequently. Two candidate factors (vitamin D deficiency and Epstein-Barr viral infection) seem particularly well-suited to the first two environmental-events but other factors (e.g., obesity and smoking behavior) seem also to be involved in the causal scheme. MS-pathogenesis can be modeled by incorporating both the environmental and genetic-factors into a causal scheme, which can then help to explain some of the changes in MS-epidemiology (e.g., increasing disease-prevalence, changing sex-ratio, and regional-variations in monozygotic-twin-concordance-rates), which have been taking place recently. This model suggests that genetic-susceptibility is overwhelmingly the most important determinant of MS and that, at least, 92.5% of individuals (and likely much more) are, essentially, incapable of developing MS, regardless of their specific environmental-exposures. Nevertheless, the genetics is complex and the contribution of any specific gene to MS-susceptibility seems to be quite modest. Thus, even for the DRB1*1501 allele (the strongest known MS-susceptibility marker), most carriers are not in the genetically-susceptible group. Moreover, 45-50% of individuals with MS lack this allele entirely and some of the haplotypes that carry this allele don't also confer any disease-risk. Finally, because the prevalence of genetic-susceptibility seems to be so similar throughout North America and Europe, and despite the crucial importance of a person's genetic make-up to disease pathogenesis, it is the environmental-factors, which largely responsible for the observed regional variations in disease-characteristics. Thus, despite MS being more common in women, men are more likely to be genetically-susceptible. This apparent paradox seems to relate to the fact that women are much more responsive than men to the recent changes in environmental-exposure (whatever these have been). These gender-differences may help to explain changes in the sex-ratio and the increasing disease-prevalence, which have both been observed recently. The potential importance of these conclusions regarding the role of environment in MS-pathogenesis is that they open the door to the possibility of pursuing strategies for primary primary disease prevention in the future.

The epidemiology of multiple sclerosis: insights to disease pathogenesis

The purpose of studying the epidemiology of multiple sclerosis (MS) is twofold. First, it is important to understand clearly the natural history of the illness in order to assist patients in making decisions about their future with respect to issues such as family planning, the importance of securing lifelong healthcare, their ability to get and maintain employment, and making appropriate choices of therapy for their particular circumstances. This is not to suggest that, even with the best possible information, the ultimate prognosis for any individual can be predicted with absolute accuracy. It cannot. Nevertheless, accurate information can be very helpful both to reassure patients that many individuals with MS do remarkably well in the long term (perhaps, especially, with current and future therapies) and also to empower individuals with respect to their ability to make their own life choices. Second, and arguably the more important purpose for studying the epidemiology of MS, is to gain insights to the underlying causes of the disease. Indeed, if the principal mechanisms of disease pathogenesis were to be understood clearly, then it might be possible to entertain notions of either a cure for existing disease or the primary prevention of future disease. Much of our current understanding of disease pathogenesis, as discussed in other chapters of this volume, has been derived from basic science investigations of animal models of MS such as experimental autoimmune encephalomyelitis (EAE), and these models have provided considerable insight both to the complexity of the mammalian immune system and to the mechanisms underlying its dysfunction in inflammatory autoimmune conditions. Nevertheless, MS is a disease of humans without any known, naturally occurring, counterpart in any nonhuman species. For this reason, the clues to disease pathogenesis provided by a study of basic epidemiologic facts regarding MS (and by a systematic consideration of their implications) are essential to a comprehensive understanding of the human illness we call MS.

Obstetrical complications and Apgar score in subjects at risk of psychosis

The objective of the study was to identify associations between a history of obstetrical complications (OCs) and the future development of symptoms indicating risk of psychosis (At Risk Mental State - ARMS). The frequency of OCs was assessed in 66 ARMS subjects, 50 subjects with the first episode of schizophrenia (FES) and 50 healthy controls. Obstetrical data was obtained from medical documentation and evaluated with the Lewis and Murray Scale. Definite OCs, according to the Lewis and Murray Scale, occurred significantly more frequently in the ARMS group compared to the controls (χ(2) = 7.79, p = 0.005; OR = 4.20, 95% CI = 1.46-12.11), as well as in the FES subjects compared to the controls (χ(2) = 8.39, p = 0.004; OR = 4.64, 95% CI = 1.56-13.20). Apgar scores in the first (Apgar 1) and the fifth minute after birth (Apgar 5) were significantly lower in the FES subjects compared to the controls (for Apgar 1 score Z = 4.439, p < 0.0001; for Apgar 5 score Z = 5.250, p < 0.0001). The ARMS subjects demonstrated significantly lower Apgar 5 scores compared to the healthy controls (Z = 3.458, p = 0.0016). The results indicate that OCs and low Apgar 5 score should be considered important factors in identifying subjects at risk of developing psychosis.

Medical record validation of maternal recall of pregnancy and birth events from a twin cohort

This study aims to assess the validity of maternal recall for several perinatal variables 8-10 years after pregnancy in a twin sample. Retrospective information was collected 8-10 years after the delivery event in a cohort of mothers from the University of Southern California Twin Study (N = 611) and compared with medical records for validity analysis. Recall of most variables showed substantial to perfect agreement (κ = 0.60-1.00), with notable exceptions for specific medical problems during pregnancy (κ ≤ 0.40) and substance use when mothers provided continuous data (e.g., number of cigarettes per day; r ≤ 0.24). With the exception of delivery method, neonatal intensive care unit admission, birth weight, neonatal information, and post-delivery complications were also recalled with low accuracy. For mothers of twins, maternal recall is generally a valid measure for perinatal variables 10 years after pregnancy. However, caution should be taken regarding variables such as substance use, medical problems, birth length, and post-delivery complications.

Obstetric complications in early psychosis: relation with family history of psychosis

The people classified as being at ultra-high risk (UHR) of developing psychosis are expected to share many risk factors for psychosis with the patients diagnosed with schizophrenia, including an enhanced incidence of obstetric complications (OCs). This study set out to investigate the incidence and correlates of OCs in a sample of patients accessing an early intervention center. Patients' mothers were asked whether they had suffered from any somatic complication during pregnancy from a list of OCs with potential direct relevance to the physical wellbeing of the offspring. Out of 86 patients diagnosed with first-episode psychosis, 20 (23%) cases were positive for the occurrence of severe OCs, as reported by their mothers during an interview; out of 83 UHR patients, 21 (25%) cases were positive for OCs. OCs were more common in individuals with a family history of psychosis than in those without such a history. OCs might interact with genetic vulnerability to increase the risk of psychosis. Lack of comparison to healthy controls is a limitation that decreases the value of these findings.

A systematic review of obstetric complications as risk factors for eating disorder and a meta-analysis of delivery method and prematurity

OBJECTIVE

The aim of this study was to systematically review the literature on obstetric factors at birth and their role as risk factors for a subsequent eating disorder (ED) and where possible to perform a meta-analysis of case-control studies of EDs and obstetric complications (OCs).

METHOD

Studies were ascertained by computer searches of electronic databases (Medline, PsycINFO, Web of Science and CINAHL), searches of reference lists and from raw data obtained upon request from the authors. A total of 14 studies were identified for the systematic review, of which 6 were eligible for the subsequent meta-analysis. Of the selected 6 studies, 5 reported on the same OCs, namely vaginal instrumental delivery and prematurity. Accordingly, meta-analyses were run on these two variables. Both analyses were conducted on anorexia nervosa (AN) patients.

RESULTS

Findings from the systematic review were conflicting, with some studies reporting a significant relationship between OCs and ED diagnoses and/or ED symptomatology and others refuting it. A non-significant association of instrumental delivery [pooled odds ratio (OR) 1.06, 95%CI: 0.69, 1.65] and prematurity [pooled OR 1.17, 95%CI: 0.91, 1.52] with AN was revealed in our meta-analysis.

CONCLUSION

The current literature on OCs as risk factors for a later ED is contradictory. The range of different occurrences considered as OCs and methodological limitations hinder ultimate conclusions. Upcoming studies should pool datasets together to obtain sufficient power to assess OCs and EDs in combination.

Epidemiology of psychiatric disorders in very young children in a Romanian pediatric setting

A growing literature demonstrates that early clinical intervention can reduce risks of adverse psychosocial outcomes. A first step necessary for developing early intervention services is to know the prevalence of clinical disorders, especially in systems that are rebuilding, such as Romania, where the mental health system was dismantled under Ceausescu. No epidemiologic studies have examined prevalence of psychiatric disorders in young children in Romania. The objective of this study was to determine the prevalence of psychiatric disorders in Romanian children 18-60 months in pediatric settings. Parents of 1,003 children 18-60 months in pediatric waiting rooms of two pediatric hospitals completed background information, the Child Behavior Checklist (CBCL). A subgroup over-sampled for high mental health problems were invited to participate in the Preschool Age Psychiatric Assessment. Rates of mental health problems were similar to the US norms on the CBCL. The weighted prevalence of psychiatric disorders in these children was 8.8%, with 5.4% with emotional disorders and 1.4% with behavioral disorders. Comorbidity occurred in nearly one-fourth of the children with a psychiatric disorder and children who met diagnostic criteria had more functional impairment than those without. Of children who met criteria for a psychiatric disorder, 10% of parents were concerned about their child's emotional or behavioral health. This study provides prevalence rates of psychiatric disorders in young Romanian children, clinical characteristic of the children and families that can guide developing system of care. Cultural differences in parental report of emotional and behavioral problems warrant further examination.

Stress-related methylation of the catechol-O-methyltransferase Val 158 allele predicts human prefrontal cognition and activity

DNA methylation at CpG dinucleotides is associated with gene silencing, stress, and memory. The catechol-O-methyltransferase (COMT) Val(158) allele in rs4680 is associated with differential enzyme activity, stress responsivity, and prefrontal activity during working memory (WM), and it creates a CpG dinucleotide. We report that methylation of the Val(158) allele measured from peripheral blood mononuclear cells (PBMCs) of Val/Val humans is associated negatively with lifetime stress and positively with WM performance; it interacts with stress to modulate prefrontal activity during WM, such that greater stress and lower methylation are related to reduced cortical efficiency; and it is inversely related to mRNA expression and protein levels, potentially explaining the in vivo effects. Finally, methylation of COMT in prefrontal cortex and that in PBMCs of rats are correlated. The relationship of methylation of the COMT Val(158) allele with stress, gene expression, WM performance, and related brain activity suggests that stress-related methylation is associated with silencing of the gene, which partially compensates the physiological role of the high-activity Val allele in prefrontal cognition and activity. Moreover, these results demonstrate how stress-related DNA methylation of specific functional alleles impacts directly on human brain physiology beyond sequence variation.

Minor physical anomalies and vulnerability in prodromal youth

Because both the brain and craniofacial/limb features originate from the same germinal layer during early gestation, the postnatal presence of minor physical anomalies (MPAs) involving these physical features may be indicative of defects in prenatal neural migration and consequent brain abnormalities among individuals with psychosis. However, to date it is unknown what symptoms and characteristics MPAs may be associated with, or how these markers may reflect vulnerability among adolescents at high-risk for developing psychosis. This information is particularly vital for understanding susceptibility and informing etiological conceptualizations such as the neural diathesis-stress model. In this study, 50 adolescents with a prodromal syndrome were evaluated for MPAs, salivary cortisol, auditory and visual memory function, and attenuated positive, negative, and disorganized symptoms. Results indicated that the participants showing elevated MPAs (n=25) were distinguished by elevated cortisol, deficit immediate and delayed visual memory, and higher levels of disorganized prodromal symptoms when compared with those participants exhibiting a lower incidence of MPAs. This was supported by supplementary correlational analyses examining the entire sample. These findings provide preliminary support for a theory that MPAs may reflect hippocampal system vulnerability among prodromal patients.

Obstetrical complications, social class and type of schizophrenia

The emerging neurodevelopmental model posits that prenatal and perinatal factors can play an etiological role in schizophrenia. Consistently, the research on obstetrical complications (OCs) reports an association with the development of more severe schizophrenic symptoms. Low socioeconomic status (SES) has also been linked to both limited prenatal healthcare and to worse prognosis of schizophrenic symptoms. A large sample (n=437) of patients from a state hospital population in the U. S. was screened for study variables. A sequential analysis was conducted, first applying cross tabulations using the chi-square test, and then building separate logit models for poor and nonpoor patients. The cross tabulations indicated an association between OCs and negative symptoms for poor schizophrenic patients, but not for nonpoor patients. Multivariate logit models further supported this result. This is the first study to examine the interaction of OCs, schizophrenic symptomatology and SES of origin.

Long-term maternal recall of obstetric complications in schizophrenia research

Obstetric complications (OCs) are consistently implicated in the aetiology of schizophrenia. Information about OCs is often gathered retrospectively, from maternal interview. It has been suggested that mothers of people with schizophrenia may not be accurate in their recollection of obstetric events. We assessed the validity of long term maternal recall by comparing maternal ratings of OCs with those obtained from medical records in a sample of mothers of offspring affected and unaffected with psychotic illness. Obstetric records were retrieved for 30 subjects affected with psychosis and 40 of their unaffected relatives. The Lewis-Murray scale of OCs was completed by maternal interview for each subject blind to the obstetric records. There was substantial agreement between maternal recall and birth records for the summary score of "definite" OCs, birth weight, and most of the individual items rated, with the exception of antepartum haemorrhage. There were no significant differences in the validity of recall or in errors of commission by mothers for affected and unaffected offspring. These findings indicate that several complications of pregnancy and delivery are accurately recalled by mother's decades after they occurred. Furthermore, there is no indication that mothers are less accurate in recalling OCs for their affected offspring than their unaffected offspring. When comparing women with and without recall errors, we found those with recall errors to have significantly worse verbal memory than women without such errors. Assessing the cognition of participants in retrospective studies may allow future studies to increase the reliability of their data.

Cerebral cortical thickness and a history of obstetric complications in schizophrenia

INTRODUCTION

Magnetic resonance imaging (MRI) studies have demonstrated that patients with schizophrenia have thinner brain cortices compared with healthy control subjects. Neurodevelopment is vulnerable to obstetric complications (OCs) such as hypoxia and birth trauma, factors that are also related to increased risk of developing schizophrenia. With the hypothesis that OCs might explain the thinner cortices found in schizophrenia, we studied patients with schizophrenia and healthy controls subjects for association between number and severity of OCs and variation in cortical thickness.

METHODS

MRI scans of 54 adults with schizophrenia or schizoaffective disorder and 54 healthy controls were acquired at Karolinska Institutet, Stockholm, Sweden. Measures of brain cortical thickness were obtained using automated computer processing (FreeSurfer). OCs were assessed from obstetric records and scored blindly according to the McNeil-Sjöström scale. At numerous cortical locations, putative effects of OCs on cortical thickness variation were tested for each trimester, for labour, for composite OC scores, severe OC scores, and hypoxia scores among patients and controls separately.

RESULTS

Number and severity of OCs varied among both patient and control subjects but were not associated with cortical thickness in either of the groups. Patients demonstrated thinner brain cortices but there were no significant differences in number and severity of OC scores across groups.

CONCLUSION

In the present study, number and severity of obstetric complications were not associated with brain cortical thickness, in patients with schizophrenia or in healthy control subjects. The thinner brain cortices found in patients with schizophrenia were not explained by a history of OCs.

Obstetric complications and risk for conversion to psychosis among individuals at high clinical risk

AIM

Examining risk factors among high-risk populations stands to inform treatment and to elucidate our understanding of the pathophysiology of schizophrenia. Despite substantial evidence implicating the incidence of obstetric complications (OCs) as a risk factor for schizophrenia, little is known about the relationship between OCs and risk for conversion among high-risk individuals.

METHODS

We prospectively followed individuals at high risk for developing psychotic disorders for a two-year period to determine if a history of OCs is associated with conversion.

RESULTS

Individuals who converted to psychosis had significantly more OCs when compared to non-converting participants; a history of OCs was associated with increased odds of conversion (odds ratio = 4.90, confidence interval :1.04/22.20). OCs were positively associated with prodromal symptomatology.

CONCLUSIONS

To date, this report represents the first empirical evidence suggesting that OCs confer increased risk of conversion to psychosis. It is possible that OCs interact with brain maturational processes in the pathophysiology of schizophrenia and can serve as a risk marker.

Obstetric complications and mild to moderate intellectual disability

BACKGROUND

Mild to moderate intellectual disability affects 2.5% of the general population and is associated with an increased risk of several psychiatric disorders. Most cases are of unknown aetiology although genetic factors have an important role.

AIMS

To investigate the role of obstetric and neonatal complications in the aetiology of mild to moderate intellectual disability.

METHOD

Obstetric and neonatal complications recorded at the time of pregnancy and delivery were compared between participants with mild to moderate intellectual disability, age-matched siblings and unrelated controls using logistic regression.

RESULTS

Admission to a special care baby unit and not being breastfed on discharge were more common in people with mild to moderate intellectual disability. Not being breastfed on discharge was also more common in those with intellectual disability than unaffected siblings. Foetal distress was more common among controls than among those with mild to moderate intellectual disability.

CONCLUSIONS

Admission to a special care baby unit and not being breastfed on discharge may be related to the aetiology of intellectual disability, although the direction of this association is unclear.

Serious obstetric complications interact with hypoxia-regulated/vascular-expression genes to influence schizophrenia risk

The etiology of schizophrenia is thought to include both epistasis and gene-environment interactions. We sought to test whether a set of schizophrenia candidate genes regulated by hypoxia or involved in vascular function in the brain (AKT1, BDNF, CAPON, CHRNA7, COMT, DTNBP1, GAD1, GRM3, NOTCH4, NRG1, PRODH, RGS4, TNF-alpha) interacted with serious obstetric complications to influence risk for schizophrenia. A family-based study of transmission disequilibrium was conducted in 116 trios. Twenty-nine probands had at least one serious obstetric complication (OC) using the McNeil-Sjostrom Scale, and many of the OCs reported were associated with the potential for fetal hypoxia. Analyses were conducted using conditional logistic regression and a likelihood ratio test (LRT) between nested models was performed to assess significance. Of the 13 genes examined, four (AKT1 (three SNPs), BDNF (two SNPs), DTNBP1 (one SNP) and GRM3 (one SNP)) showed significant evidence for gene-by-environment interaction (LRT P-values ranged from 0.011 to 0.037). Although our sample size was modest and the power to detect interactions was limited, we report significant evidence for genes involved in neurovascular function or regulated by hypoxia interacting with the presence of serious obstetric complications to increase risk for schizophrenia.

The effects of genetic liability for schizophrenia and maternal smoking during pregnancy on obstetric complications

The purpose of this study was to determine whether a genetic vulnerability for schizophrenia and/or health-risk behaviors among schizophrenic pregnant women were associated with an increased incidence of obstetric complications (OCs).

METHOD

A high-risk birth cohort was formed by searching the Finnish Perinatal Register for all births from 1991-2000 with arterial cord pH values below 7.20, an indication of fetal asphyxia. This database was merged with national hospital discharge registries to determine psychiatric morbidity of the mothers and the mothers' first-degree relatives. Mothers were divided into 3 groups: women diagnosed with schizophrenia/schizoaffective disorder (n=53), mothers with a first-degree relative with schizophrenia/schizoaffective disorder (n=590) and healthy controls (n=36,895).

RESULT

Schizophrenic women had significantly more OCs than mothers with a first-degree schizophrenic relative and controls. These women had significantly increased rates of eclampsia, premature delivery, prenatal hospitalizations, and marginally significant increases in high blood pressure. Offspring of schizophrenic mothers had significantly decreased APGAR scores and birth weight and increased medical complications after birth. In contrast, women with a schizophrenic first-degree relative had no significant increases in OCs compared to controls. Schizophrenic mothers also smoked more than the other groups and smoking was found to mediate the relationship between maternal schizophrenic status and decreased birth weight among offspring.

CONCLUSIONS

Maternal schizophrenia during pregnancy leads to an increased risk of OCs, possibly due to engagement in health-risk behaviors during pregnancy, such as smoking, whereas genetic susceptibility to schizophrenia, by itself, does not appear to be related to incidence of OCs.

Severe obstetric complications and birth characteristics in preterm or term delivery were accurately recalled by mothers

OBJECTIVE

This study examined the accuracy of maternal recall of obstetric complications and birth characteristics and its determinants for both preterm and term deliveries 3-9 years ago.

METHODS

In 101 preterm and 107 term deliveries at the National Taiwan University Hospital during 1995-2000, recall data were obtained by telephone interview with the mothers and were matched with medical records.

RESULTS

Among 10 obstetric complications assessed, the accuracy of maternal recall could either have high sensitivity and high specificity (Cesarean section, gestational hypertension, and induced labor), low to moderate sensitivity and high specificity (pre-eclampsia, breech, and cord loops), or low sensitivity and low specificity (ante partum vaginal bleeding, edema, and proteinuria). The correlations between maternal recall and medical records for birth weight (r = .95) and gestational age (r =.93) in the preterm group were slightly higher than those in the term group (r = .89 and .83, respectively). Factors associated with higher recall accuracy included preterm delivery, first birth order, and lower total parity, but no factor consistently related to maternal accuracy for all obstetric complications and birth characteristics.

CONCLUSION

The accuracy of maternal recall on obstetric complications varied depending on the nature of complications examined, whereas that on birth characteristics was high.

Lack of evidence for elevated obstetric complications in childhood onset schizophrenia

BACKGROUND

Pre-, peri-, and postnatal obstetric complications (OC) are reported to be more frequent in adult patients with schizophrenia and have been linked to both greater severity and to "earlier" age of onset (before either age 18 or 22) in studies of adult patients. We hypothesized that by extrapolation, patients with childhood-onset schizophrenia (COS), with very early onset and very severe illness, would have had more numerous or more salient OC compared with their healthy siblings.

METHODS

We compared the obstetric records of 60 COS children and 48 healthy siblings using the Columbia Obstetrics Complication Scale, a comprehensive measurement scale consisting of 37 variables having included a separate scale for fetal hypoxia.

RESULTS

Patients with COS did not have a higher incidence of OC than the healthy sibling control group with the exception of increased incidence of maternal vomiting.

CONCLUSIONS

Obstetric complications, with the possible exception of maternal vomiting, are unlikely to play a major role in the etiopathogenesis of childhood-onset schizophrenia.

Early maternal stress and health behaviours and offspring expression of psychosis in adolescence

OBJECTIVE

It has been suggested that influences operating early in life may affect the risk of postpubertal psychosis outcomes. This hypothesis was tested using a broad outcome of psychotic symptoms expressed in adolescence (prevalence: 15.6%).

METHOD

Findings are based on a longitudinal, population-based cohort study of 963 adolescents aged 15-20 years and their parents in the area of Munich, Germany. Trained psychologists assessed adolescents with the Munich-Composite International Diagnostic Interview. Independently, direct diagnostic interviews were conducted with the parents.

RESULTS

A range of medical complications of pregnancy and delivery, including lower birth weight, were not associated with the psychosis outcome. However, a number of maternal health behaviours and experiences did show associations, independent of confounders.

CONCLUSION

Not maternally reported medical complications of pregnancy and delivery, but maternal prenatal health behaviours predicted expression of psychosis along a continuum in adolescence. This effect may either be direct or constitute a proxy for later postnatal maternal behaviours associated with psychosis risk in the offspring.

Poor maternal care and high maternal body mass index in pregnancy as a risk factor for schizophrenia in offspring

OBJECTIVE

We investigated whether antenatal factors in mothers would increase the risk of schizophrenia in the offspring, and also examined any relationship between these factors and histories of obstetric complications (OCs).

METHOD

Using the Mother and Child Health Handbooks of 52 patients with schizophrenia and 284 healthy subjects, we evaluated the risk-increasing effects of the frequency of antenatal care visits and mothers' body mass index (BMI) at both early and late pregnancy.

RESULTS

In logistic regression analysis, there was a significant association between the number of antenatal care visits and the risk of the disorder; an increase in a unit of visits corresponds to a reduction of the risk by 12%. We also found a 24% increase in the risk with a one-unit increase of BMI at the early pregnancy, and a 19% increase at the late pregnancy. These antenatal factors were found to contribute, in part, to an excess of OCs in individuals with schizophrenia.

CONCLUSION

Poor maternal care during pregnancy and comparatively high maternal BMI especially at early pregnancy may cause a predisposition to schizophrenia in the offspring.

Severity of obstetric complications and risk of adult schizophrenia in male patients: a case-control study

OBJECTIVE

Obstetric complications may be an etiologically important factor in the development of schizophrenia. The aim of this study was to evaluate whether the risk for developing schizophrenia in adult life is increased in individuals with more severe obstetric complications at birth.

METHODS

To this end, mothers were interviewed to gather data about obstetric complications. The 'midwife protocol' of Parnas and colleagues was used to quantify the presence and entity of obstetric complications. We studied the frequency distribution and the severity of obstetric complications in 64 male DSM IV schizophrenic patients. The genetic load was reduced by using 81 brothers who were not psychiatric patients as controls. Odds ratios for the effects of obstetric complications, maternal age, birth order and birth weight were calculated using conditional logistic regression.

RESULTS

The only factor found to have a significant effect on the risk of schizophrenia was the overall measure of obstetric complications at birth. The history of obstetric complications was higher in schizophrenic patients than in their siblings.

CONCLUSION

The results seem to confirm the hypothesis that obstetric complications may contribute to increased vulnerability to the disease, in addition to genetic risk factors.