Obstetric risk factors for early-onset schizophrenia in a Finnish birth cohort

Difficulties during delivery, brain ventricle enlargement and cognitive impairment in first episode psychosis

BACKGROUND

Patients with a first episode of psychosis (FEP) display clinical, cognitive, and structural brain abnormalities at illness onset. Ventricular enlargement has been identified in schizophrenia since the initial development of neuroimaging techniques. Obstetric abnormalities have been associated with an increased risk of developing psychosis but also with cognitive impairment and brain structure abnormalities. Difficulties during delivery are associated with a higher risk of birth asphyxia leading to brain structural abnormalities, such as ventriculomegaly, which has been related to cognitive disturbances.

METHODS

We examined differences in ventricular size between 142 FEP patients and 123 healthy control participants using magnetic resonance imaging. Obstetric complications were evaluated using the Lewis-Murray scale. We examined the impact of obstetric difficulties during delivery on ventricle size as well as the possible relationship between ventricle size and cognitive impairment in both groups.

RESULTS

FEP patients displayed significantly larger third ventricle size compared with healthy controls. Third ventricle enlargement was associated with diagnosis (higher volume in patients), with difficulties during delivery (higher volume in subjects with difficulties), and was highest in patients with difficulties during delivery. Verbal memory was significantly associated with third ventricle to brain ratio.

CONCLUSIONS

Our results suggest that difficulties during delivery might be significant contributors to the ventricular enlargement historically described in schizophrenia. Thus, obstetric complications may contribute to the development of psychosis through changes in brain architecture.

Human Cord Blood Endothelial Progenitor Cells and Pregnancy Complications (Preeclampsia, Gestational Diabetes Mellitus, and Fetal Growth Restriction)

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare-through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence-the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development.

Network-Based Spreading of Gray Matter Changes Across Different Stages of Psychosis

Importance

Psychotic illness is associated with anatomically distributed gray matter reductions that can worsen with illness progression, but the mechanisms underlying the specific spatial patterning of these changes is unknown.

Objective

To test the hypothesis that brain network architecture constrains cross-sectional and longitudinal gray matter alterations across different stages of psychotic illness and to identify whether certain brain regions act as putative epicenters from which volume loss spreads.

Design, Settings, and Participants

This case-control study included 534 individuals from 4 cohorts, spanning early and late stages of psychotic illness. Early-stage cohorts included patients with antipsychotic-naive first-episode psychosis (n = 59) and a group of patients receiving medications within 3 years of psychosis onset (n = 121). Late-stage cohorts comprised 2 independent samples of people with established schizophrenia (n = 136). Each patient group had a corresponding matched control group (n = 218). A sample of healthy adults (n = 356) was used to derive representative structural and functional brain networks for modeling of network-based spreading processes. Longitudinal illness-related and antipsychotic-related gray matter changes over 3 and 12 months were examined using a triple-blind randomized placebo-control magnetic resonance imaging study of the antipsychotic-naive patients. All data were collected between April 29, 2008, and January 15, 2020, and analyses were performed between March 1, 2021, and January 14, 2023.

Main Outcomes and Measures

Coordinated deformation models were used to estimate the extent of gray matter volume (GMV) change in each of 332 parcellated areas by the volume changes observed in areas to which they were structurally or functionally coupled. To identify putative epicenters of volume loss, a network diffusion model was used to simulate the spread of pathology from different seed regions. Correlations between estimated and empirical spatial patterns of GMV alterations were used to quantify model performance.

Results

Of 534 included individuals, 354 (66.3%) were men, and the mean (SD) age was 28.4 (7.4) years. In both early and late stages of illness, spatial patterns of cross-sectional volume differences between patients and controls were more accurately estimated by coordinated deformation models constrained by structural, rather than functional, network architecture (r range, >0.46 to <0.57; P < .01). The same model also robustly estimated longitudinal volume changes related to illness (r ≥ 0.52; P < .001) and antipsychotic exposure (r ≥ 0.50; P < .004). Network diffusion modeling consistently identified, across all 4 data sets, the anterior hippocampus as a putative epicenter of pathological spread in psychosis. Epicenters of longitudinal GMV loss were apparent in posterior cortex early in the illness and shifted to the prefrontal cortex with illness progression.

Conclusion and Relevance

These findings highlight a central role for white matter fibers as conduits for the spread of pathology across different stages of psychotic illness, mirroring findings reported in neurodegenerative conditions. The structural connectome thus represents a fundamental constraint on brain changes in psychosis, regardless of whether these changes are caused by illness or medication. Moreover, the anterior hippocampus represents a putative epicenter of early brain pathology from which dysfunction may spread to affect connected areas.

The synaptic hypothesis of schizophrenia version III: a master mechanism

The synaptic hypothesis of schizophrenia has been highly influential. However, new approaches mean there has been a step-change in the evidence available, and some tenets of earlier versions are not supported by recent findings. Here, we review normal synaptic development and evidence from structural and functional imaging and post-mortem studies that this is abnormal in people at risk and with schizophrenia. We then consider the mechanism that could underlie synaptic changes and update the hypothesis. Genome-wide association studies have identified a number of schizophrenia risk variants converging on pathways regulating synaptic elimination, formation and plasticity, including complement factors and microglial-mediated synaptic pruning. Induced pluripotent stem cell studies have demonstrated that patient-derived neurons show pre- and post-synaptic deficits, synaptic signalling alterations, and elevated, complement-dependent elimination of synaptic structures compared to control-derived lines. Preclinical data show that environmental risk factors linked to schizophrenia, such as stress and immune activation, can lead to synapse loss. Longitudinal MRI studies in patients, including in the prodrome, show divergent trajectories in grey matter volume and cortical thickness compared to controls, and PET imaging shows in vivo evidence for lower synaptic density in patients with schizophrenia. Based on this evidence, we propose version III of the synaptic hypothesis. This is a multi-hit model, whereby genetic and/or environmental risk factors render synapses vulnerable to excessive glia-mediated elimination triggered by stress during later neurodevelopment. We propose the loss of synapses disrupts pyramidal neuron function in the cortex to contribute to negative and cognitive symptoms and disinhibits projections to mesostriatal regions to contribute to dopamine overactivity and psychosis. It accounts for the typical onset of schizophrenia in adolescence/early adulthood, its major risk factors, and symptoms, and identifies potential synaptic, microglial and immune targets for treatment.

Lost in Translation: Challenges in the Diagnosis and Treatment of Early-Onset Schizophrenia

Early-onset schizophrenia (EOS) is a heterogeneous condition that has a serious, insidious clinical course and poor long-term mental health outcomes. The clinical presentations are highly complex due to the overlapping symptomatology with other illnesses, which contributes to a delay in the diagnosis. The objective of the review is to study if an earlier age of onset (AAO) of EOS has poor clinical outcomes, the diagnostic challenges of EOS, and effective treatment strategies. The review provides a comprehensive literature search of 5966 articles and summarizes 126 selected for empirical evidence to methodically consider challenges in diagnosing and treating EOS for practicing clinicians. The risk factors of EOS are unique but have been shared with many other neuropsychiatric illnesses. Most of the risk factors, including genetics and obstetric complications, are nonmodifiable. The role of early diagnosis in reducing the duration of untreated psychosis (DUP) remains critical to reducing overall morbidity. Many specific issues contribute to the risk and clinical outcomes. Therefore, issues around diagnostic ambiguity, treatment resistance, nonadherence, and rehospitalizations further extend the DUP. There is hesitancy to initiate clozapine early, even though the empirical evidence strongly supports its use. There is a growing body of research that suggests the use of long-acting injectables to address nonadherence, and these measures are largely underutilized in acute settings. The clinical presentations of EOS are complex. In addition to the presence of specific risk factors, patients with an early onset of illness are also at a higher risk for treatment resistance. While there is a need to develop tools for early diagnosis, established evidence-based measures to address nonadherence, psychoeducation, and resistance must be incorporated into the treatment planning.

Early magnetic resonance imaging biomarkers of schizophrenia spectrum disorders: Toward a fetal imaging perspective

There is mounting evidence to implicate the intrauterine environment as the initial pathogenic stage for neuropsychiatric disease. Recent developments in magnetic resonance imaging technology are making a multimodal analysis of the fetal central nervous system a reality, allowing analysis of structural and functional parameters. Exposures to a range of pertinent risk factors whether preconception or in utero can now be indexed using imaging techniques within the fetus' physiological environment. This approach may determine the first "hit" required for diseases that do not become clinically manifest until adulthood, and which only have subtle clinical markers during childhood and adolescence. A robust characterization of a "multi-hit" hypothesis may necessitate a longitudinal birth cohort; within this investigative paradigm, the full range of genetic and environmental risk factors can be assessed for their impact on the early developing brain. This will lay the foundation for the identification of novel biomarkers and the ability to devise methods for early risk stratification and disease prevention. However, these early markers must be followed over time: first, to account for neural plasticity, and second, to assess the effects of postnatal exposures that continue to drive the individual toward disease. We explore these issues using the schizophrenia spectrum disorders as an illustrative paradigm. However, given the potential richness of fetal magnetic resonance imaging, and the likely overlap of biomarkers, these concepts may extend to a range of neuropsychiatric conditions.

Carbonic anhydrase inhibitors suppress seizures in a rat model of birth asphyxia

OBJECTIVE

Seizures are common in neonates recovering from birth asphyxia but there is general consensus that current pharmacotherapy is suboptimal and that novel antiseizure drugs are needed. We recently showed in a rat model of birth asphyxia that seizures are triggered by the post-asphyxia recovery of brain pH. Here our aim was to investigate whether carbonic anhydrase inhibitors (CAIs), which induce systemic acidosis, block the post-asphyxia seizures.

METHODS

The CAIs acetazolamide (AZA), benzolamide (BZA), and ethoxzolamide (EZA) were administered intraperitoneally or intravenously to 11-day-old rats exposed to intermittent asphyxia (30 min; three 7+3 min cycles of 9% and 5% O₂ at 20% CO₂ ). Electrode measurements of intracortical pH, Po₂ , and local field potentials (LFPs) were made under urethane anesthesia. Convulsive seizures and blood acid-base parameters were examined in freely behaving animals.

RESULTS

The three CAIs decreased brain pH by 0.14-0.17 pH units and suppressed electrographic post-asphyxia seizures. AZA, BZA, and EZA differ greatly in their lipid solubility (EZA > AZA > BZA) and pharmacokinetics. However, there were only minor differences in the delay (range 0.8-3.7 min) from intraperitoneal application to their action on brain pH. The CAIs induced a modest post-asphyxia elevation of brain Po₂ that had no effect on LFP activity. AZA was tested in freely behaving rats, in which it induced a respiratory acidosis and decreased the incidence of convulsive seizures from 9 of 20 to 2 of 17 animals.

SIGNIFICANCE

AZA, BZA, and EZA effectively block post-asphyxia seizures. Despite the differences in their pharmacokinetics, they had similar effects on brain pH, which indicates that their antiseizure mode of action was based on respiratory (hypercapnic) acidosis resulting from inhibition of blood-borne and extracellular vascular carbonic anhydrases. AZA has been used for several indications in neonates, suggesting that it can be safely repurposed for the treatment of neonatal seizures as an add-on to the current treatment regimen.

A physiologically validated rat model of term birth asphyxia with seizure generation after, not during, brain hypoxia

OBJECTIVE

Birth asphyxia (BA) is often associated with seizures that may exacerbate the ensuing hypoxic-ischemic encephalopathy. In rodent models of BA, exposure to hypoxia is used to evoke seizures, that commence already during the insult. This is in stark contrast to clinical BA, in which seizures are typically seen upon recovery. Here, we introduce a term-equivalent rat model of BA, in which seizures are triggered after exposure to asphyxia.

METHODS

Postnatal day 11-12 male rat pups were exposed to steady asphyxia (15 min; air containing 5% O2  + 20% CO2 ) or to intermittent asphyxia (30 min; three 5 + 5-min cycles of 9% and 5% O2 at 20% CO2 ). Cortical activity and electrographic seizures were recorded in freely behaving animals. Simultaneous electrode measurements of intracortical pH, Po2 , and local field potentials (LFPs) were made under urethane anesthesia.

RESULTS

Both protocols decreased blood pH to <7.0 and brain pH from 7.3 to 6.7 and led to a fall in base excess by 20 mmol·L-1 . Electrographic seizures with convulsions spanning the entire Racine scale were triggered after intermittent but not steady asphyxia. In the presence of 20% CO2 , brain Po2 was only transiently affected by 9% ambient O2 but fell below detection level during the steps to 5% O2 , and LFP activity was nearly abolished. Post-asphyxia seizures were strongly suppressed when brain pH recovery was slowed down by 5% CO2 .

SIGNIFICANCE

The rate of brain pH recovery has a strong influence on post-asphyxia seizure propensity. The recurring hypoxic episodes during intermittent asphyxia promote neuronal excitability, which leads to seizures only after the suppressing effect of the hypercapnic acidosis is relieved. The present rodent model of BA is to our best knowledge the first one in which, consistent with clinical BA, behavioral and electrographic seizures are triggered after and not during the BA-mimicking insult.

Molecular mechanisms of psychiatric diseases

For most psychiatric diseases, pathogenetic concepts as well as paradigms underlying neuropsychopharmacologic approaches currently revolve around neurotransmitters such as dopamine, serotonin, and norepinephrine. However, despite the fact that several generations of neurotransmitter-based psychotropics including atypical antipsychotics, selective serotonin reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors are available, the effectiveness of these medications is limited, and relapse rates in psychiatric diseases are relatively high, indicating potential involvement of other pathogenetic pathways. Indeed, recent high-throughput studies in genetics and molecular biology have shown that pathogenesis of major psychiatric illnesses involves hundreds of genes and numerous pathways via such fundamental processes as DNA methylation, transcription, and splicing. Current review summarizes these and other molecular mechanisms of such psychiatric illnesses as schizophrenia, major depressive disorder, and alcohol use disorder and suggests a conceptual framework for future studies.

Enlarged hippocampal fissure in psychosis of epilepsy

Psychosis of epilepsy (POE) can be a devastating condition, and its neurobiological basis remains unclear. In a previous study, we identified reduced posterior hippocampal volumes in patients with POE. The hippocampus can be further subdivided into anatomically and functionally distinct subfields that, along with the hippocampal fissure, have been shown to be selectively affected in other psychotic disorders and are not captured by gross measures of hippocampal volume. Therefore, in this study, we compared the volume of selected hippocampal subfields and the hippocampal fissure in 31 patients with POE with 31 patients with epilepsy without psychosis. Cortical reconstruction, volumetric segmentation, and calculation of hippocampal subfields and the hippocampal fissure were performed using FreeSurfer. The group with POE had larger hippocampal fissures bilaterally compared with controls with epilepsy, which was significant on the right. There were no significant differences in the volumes of the hippocampal subfields between the two groups. Our findings suggest abnormal development of the hippocampus in POE. They support and expand the neurodevelopmental model of psychosis, which holds that early life stressors lead to abnormal neurodevelopmental processes, which underpin the onset of psychosis in later life. In line with this model, the findings of the present study suggest that enlarged hippocampal fissures may be a biomarker of abnormal neurodevelopment and risk for psychosis in patients with epilepsy.

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

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

Prenatal and perinatal risk and protective factors for psychosis: a systematic review and meta-analysis

BACKGROUND

Prenatal and perinatal insults are implicated in the aetiopathogenesis of psychotic disorders but the consistency and magnitude of their associations with psychosis have not been updated for nearly two decades. The aim of this systematic review and meta-analysis was to provide a comprehensive and up-to-date synthesis of the evidence on the association between prenatal or perinatal risk and protective factors and psychotic disorders.

METHODS

In this systematic review and meta-analysis, we searched the Web of Science database for articles published up to July 20, 2019. We identified cohort and case-control studies examining the association (odds ratio [OR]) between prenatal and perinatal factors and any International Classification of Diseases (ICD) or Diagnostic and Statistical Manual of Mental Disorders (DSM) non-organic psychotic disorder with a healthy comparison group. Other inclusion criteria were enough data available to do the analyses, and non-overlapping datasets. We excluded reviews, meta-analyses, abstracts or conference proceedings, and articles with overlapping datasets. Data were extracted according to EQUATOR and PRISMA guidelines. Extracted variables included first author, publication year, study type, sample size, type of psychotic diagnosis (non-affective psychoses or schizophrenia-spectrum disorders, affective psychoses) and diagnostic instrument (DSM or ICD and version), the risk or protective factor, and measure of association (primary outcome). We did random-effects pairwise meta-analyses, Q statistics, I² index, sensitivity analyses, meta-regressions, and assessed study quality and publication bias. The study protocol was registered at PROSPERO, CRD42017079261.

FINDINGS

152 studies relating to 98 risk or protective factors were eligible for analysis. Significant risk factors were: maternal age younger than 20 years (OR 1·17) and 30-34 years (OR 1·05); paternal age younger than 20 years (OR 1·31) and older than 35 years (OR 1·28); any maternal (OR 4·60) or paternal (OR 2·73) psychopathology; maternal psychosis (OR 7·61) and affective disorder (OR 2·26); three or more pregnancies (OR 1·30); herpes simplex 2 (OR 1·35); maternal infections not otherwise specified (NOS; OR 1·27); suboptimal number of antenatal visits (OR 1·83); winter (OR 1·05) and winter to spring (OR 1·05) season of birth in the northern hemisphere; maternal stress NOS (OR 2·40); famine (OR 1·61); any famine or nutritional deficits in pregnancy (OR 1·40); maternal hypertension (OR 1·40); hypoxia (OR 1·63); ruptured (OR 1·86) and premature rupture (OR 2·29) of membranes; polyhydramnios (OR 3·05); definite obstetric complications NOS (OR 1·83); birthweights of less than 2000 g (OR 1·84), less than 2500 g (OR 1·53), or 2500-2999 g (OR 1·23); birth length less than 49 cm (OR 1·17); small for gestational age (OR 1·40); premature birth (OR 1·35), and congenital malformations (OR 2·35). Significant protective factors were maternal ages 20-24 years (OR 0·93) and 25-29 years (OR 0·92), nulliparity (OR 0·91), and birthweights 3500-3999 g (OR 0·90) or more than 4000 g (OR 0·86). The results were corrected for publication biases; sensitivity and meta-regression analyses confirmed the robustness of these findings for most factors.

INTERPRETATION

Several prenatal and perinatal factors are associated with the later onset of psychosis. The updated knowledge emerging from this study could refine understanding of psychosis pathogenesis, enhance multivariable risk prediction, and inform preventive strategies.

FUNDING

None.

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 pre-pregnancy weight status and health care use for mental health conditions in the offspring

The objective of this study was to examine the relationship between pre-pregnancy maternal weight status and offspring physician visits for mental health conditions in childhood and adolescence. We conducted a population-based retrospective cohort study of singleton infants born between the years of 1989 and 1993 using a linkage of the Nova Scotia Atlee Perinatal Database with administrative health data. Offspring were followed from birth to age 18 years. Maternal weight status was categorized according to WHO body mass index cutoffs. The number of physician visits for any mental health condition, mood, anxiety, and adjustment disorders, conduct disorder, and attention-deficit hyperactivity disorder (ADHD) from age 0-18 years was determined from ICD codes in physician billings and hospital discharge abstract data. Negative binomial regression adjusting for sociodemographics, maternal psychiatric disorders and smoking was used to model the association. In total, 38,211 mother-offspring pairs were included in the cohort. Within the first 18 years of life, offspring of mothers with obesity had significantly more physician visits for any mental health condition [adjusted incidence rate ratio (IRR) 1.26, 95% CI 1.19-1.34], mood, anxiety, and adjustment disorders (IRR 1.16, 95% CI 1.07-1.25), conduct disorder (IRR 1.25, 95% CI 1.08-1.45), and ADHD (IRR 1.45, 95% CI 1.24-1.69) compared to mothers of normal weight. Associations for mood, anxiety, and adjustment disorders and conduct disorder were strongest at 13-18 years. Offspring of mothers with obesity appear to use health care for mental health conditions more frequently than offspring of normal weight mothers.

Non-Genetic Factors in Schizophrenia

PURPOSE OF REVIEW

We review recent developments on risk factors in schizophrenia.

RECENT FINDINGS

The way we think about schizophrenia today is profoundly different from the way this illness was seen in the twentieth century. We now know that the etiology of schizophrenia is multifactorial and reflects an interaction between genetic vulnerability and environmental contributors. Environmental risk factors such as pregnancy and birth complications, childhood trauma, migration, social isolation, urbanicity, and substance abuse, alone and in combination, acting at a number of levels over time, influence the individual's likelihood to develop the disorder. Environmental risk factors together with the identification of a polygenic risk score for schizophrenia, research on gene-environment interaction and environment-environment interaction have hugely increased our knowledge of the disorder.

Obstetric complications in women with schizophrenia

Pregnancy, childbirth and motherhood are new situations for women and require adjustment. Women suffering from schizophrenia require special attention due to the course of the disease. Physiological changes that occur in the body during pregnancy may be unacceptable for women suffering from schizophrenia. They may delusively deny the existence of the pregnancy, lead an unhealthy lifestyle (stimulants, poor diet, lack of gynaecological check-ups), which in turn causes an increased risk of complications. In the research conducted so far, it has been proven that three kinds of complications are associated with schizophrenia: complications concerning pregnancy itself (bleeding, diabetes, Rh-incompatibility, pre-eclampsia), intrauterine growth restriction (low birth weight, congenital malformations, small head circumference) and complications regarding labour (uterine atony, asphyxia, emergency Caesarean section). The course of the labour itself in this specific group of patients has not yet been sufficiently examined. It has also been proven that perinatal complications are one of the factors determining an increased risk of schizophrenia.

Use of Machine Learning to Determine Deviance in Neuroanatomical Maturity Associated With Future Psychosis in Youths at Clinically High Risk

IMPORTANCE

Altered neurodevelopmental trajectories are thought to reflect heterogeneity in the pathophysiologic characteristics of schizophrenia, but whether neural indicators of these trajectories are associated with future psychosis is unclear.

OBJECTIVE

To investigate distinct neuroanatomical markers that can differentiate aberrant neurodevelopmental trajectories among clinically high-risk (CHR) individuals.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective longitudinal multicenter study, a neuroanatomical-based age prediction model was developed using a supervised machine learning technique with T1-weighted magnetic resonance imaging scans of 953 healthy controls 3 to 21 years of age from the Pediatric Imaging, Neurocognition, and Genetics (PING) study and then applied to scans of 275 CHR individuals (including 39 who developed psychosis) and 109 healthy controls 12 to 21 years of age from the North American Prodrome Longitudinal Study 2 (NAPLS 2) for external validation and clinical application. Scans from NAPLS 2 were collected from January 15, 2010, to April 30, 2012.

MAIN OUTCOMES AND MEASURES

Discrepancy between neuroanatomical-based predicted age (hereafter referred to as brain age) and chronological age.

RESULTS

The PING-derived model (460 females and 493 males; age range, 3-21 years) accurately estimated the chronological ages of the 109 healthy controls in the NAPLS 2 (43 females and 66 males; age range, 12-21 years), providing evidence of independent external validation. The 275 CHR individuals in the NAPLS 2 (111 females and 164 males; age range, 12-21 years) showed a significantly greater mean (SD) gap between model-predicted age and chronological age (0.64 [2.16] years) compared with healthy controls (P = .008). This outcome was significantly moderated by chronological age, with brain age systematically overestimating the ages of CHR individuals who developed psychosis at ages 12 to 17 years but not the brain ages of those aged 18 to 21 years. Greater brain age deviation was associated with a higher risk for developing psychosis (F = 3.70; P = .01) and a pattern of stably poor functioning over time, but only among younger CHR adolescents. Previously reported evidence of accelerated reduction in cortical thickness among CHR individuals who developed psychosis was found to apply only to those who were 18 years of age or older.

CONCLUSIONS AND RELEVANCE

These results are consistent with the view that neuroanatomical markers of schizophrenia may help to explain some of the heterogeneity of this disorder, particularly with respect to early vs later age of onset of psychosis, with younger and older individuals having differing intercepts and trajectories in structural brain parameters as a function of age. The results also suggest that baseline neuroanatomical measures are likely to be useful in estimating onset of psychosis, especially (or only) among CHR individuals with an earlier age of onset of prodromal symptoms.

Perinatal hypoxia as a risk factor for psychopathology later in life: the role of dopamine and neurotrophins

Brain development is influenced by various prenatal, intrapartum, and postnatal events which may interact with genotype to affect the neural and psychophysiological systems related to emotions, specific cognitive functions (e.g., attention, memory), and language abilities and thereby heighten the risk for psychopathology later in life. Fetal hypoxia (intrapartum oxygen deprivation), hypoxia-related obstetric complications, and hypoxia during the early neonatal period are major environmental risk factors shown to be associated with an increased risk for later psychopathology. Experimental models of perinatal hypoxia/ischemia (PHI) showed that fetal hypoxia-a consequence common to many birth complications in humans-results in selective long-term disturbances of the dopaminergic systems that persist in adulthood. On the other hand, neurotrophic signaling is critical for pre- and postnatal brain development due to its impact on the process of neuronal development and its reaction to perinatal stress. The aim of this review is (a) to summarize epidemiological data confirming an association of PHI with an increased risk of a range of psychiatric disorders from childhood through adolescence to adulthood, (b) to present immunohistochemical findings on human autopsy material indicating vulnerability of the dopaminergic neurons of the human neonate to PHI that could predispose infant survivors of PHI to dopamine-related neurological and/or cognitive deficits in adulthood, and

Role of Placental VDR Expression and Function in Common Late Pregnancy Disorders

Vitamin D, besides its classical role in bone metabolism, plays a distinct role in multiple pathways of the feto-maternal unit. Calcitriol is the major active ligand of the nuclear vitamin D receptor (VDR). The vitamin D receptor (VDR) is expressed in different uteroplacental parts and exerts a variety of functions in physiologic pregnancy. It regulates decidualisation and implantation, influences hormone secretion and placental immune modulations. This review highlights the role of the vitamin D receptor in physiologic and disturbed pregnancy, as preeclampsia, fetal growth restriction, gestational diabetes and preterm birth. We discuss the existing literature regarding common VDR polymorphisms in these pregnancy disorders.

Expression of Biglycan in First Trimester Chorionic Villous Sampling Placental Samples and Altered Function in Telomerase-Immortalized Microvascular Endothelial Cells

OBJECTIVE

Biglycan (BGN) has reduced expression in placentae from pregnancies complicated by fetal growth restriction (FGR). We used first trimester placental samples from pregnancies with later small for gestational age (SGA) infants as a surrogate for FGR. The functional consequences of reduced BGN and the downstream targets of BGN were determined. Furthermore, the expression of targets was validated in primary placental endothelial cells isolated from FGR or control pregnancies. APPROACH AND RESULTS: BGN expression was determined using real-time polymerase chain reaction in placental tissues collected during chorionic villous sampling performed at 10 to 12 weeks' gestation from pregnancies that had known clinical outcomes, including SGA. Short-interference RNA reduced BGN expression in telomerase-immortalized microvascular endothelial cells, and the effect on proliferation, angiogenesis, and thrombin generation was determined. An angiogenesis array identified downstream targets of BGN, and their expression in control and FGR primary placental endothelial cells was validated using real-time polymerase chain reaction. Reduced BGN expression was observed in SGA placental tissues. BGN reduction decreased network formation of telomerase-immortalized microvascular endothelial cells but did not affect thrombin generation or cellular proliferation. The array identified target genes, which were further validated: angiopoetin 4 (ANGPT4), platelet-derived growth factor receptor α (PDGFRA), tumor necrosis factor superfamily member 15 (TNFSF15), angiogenin (ANG), serpin family C member 1 (SERPIN1), angiopoietin 2 (ANGPT2), and CXC motif chemokine 12 (CXCL12) in telomerase-immortalized microvascular endothelial cells and primary placental endothelial cells obtained from control and FGR pregnancies.

CONCLUSIONS

This study reports a temporal relationship between altered placental BGN expression and subsequent development of SGA. Reduction of BGN in vascular endothelial cells leads to disrupted network formation and alterations in the expression of genes involved in angiogenesis. Therefore, differential expression of these may contribute to aberrant angiogenesis in SGA pregnancies.

Elevated kynurenine pathway metabolism during neurodevelopment: Implications for brain and behavior

The kynurenine pathway (KP) of tryptophan degradation contains several neuroactive metabolites that may influence brain function in health and disease. Mounting focus has been dedicated to investigating the role of these metabolites during neurodevelopment and elucidating their involvement in the pathophysiology of psychiatric disorders with a developmental component, such as schizophrenia. In this review, we describe the changes in KP metabolism in the brain from gestation until adulthood and illustrate how environmental and genetic factors affect the KP during development. With a particular focus on kynurenic acid, the antagonist of α7 nicotinic acetylcholine (α7nACh) and N-methyl-d-aspartate (NMDA) receptors, both implicated in modulating brain development, we review animal models designed to ascertain the role of perinatal KP elevation on long-lasting biochemical, neuropathological, and behavioral deficits later in life. We present new data demonstrating that combining perinatal choline-supplementation, to potentially increase activation of α7nACh receptors during development, with embryonic kynurenine manipulation is effective in attenuating cognitive impairments in adult rat offspring. With these findings in mind, we conclude the review by discussing the advancement of therapeutic interventions that would target not only symptoms, but potentially the root cause of central nervous system diseases that manifest from a perinatal KP insult. This article is part of the Special Issue entitled 'The Kynurenine Pathway in Health and Disease'.

Protein Interaction Networks Link Schizophrenia Risk Loci to Synaptic Function

Schizophrenia is a severe and highly heritable psychiatric disorder affecting approximately 1% of the population. Genome-wide association studies have identified 108 independent genetic loci with genome-wide significance but their functional importance has yet to be elucidated. Here, we develop a novel strategy based on network analysis of protein-protein interactions (PPI) to infer biological function associated with variants most strongly linked to illness risk. We show that the schizophrenia loci are strongly linked to synaptic transmission (P _FWE < .001) and ion transmembrane transport (P _FWE = .03), but not to ontological categories previously found to be shared across psychiatric illnesses. We demonstrate that brain expression of risk-linked genes within the identified processes is strongly modulated during birth and identify a set of synaptic genes consistently changed across multiple brain regions of adult schizophrenia patients. These results suggest synaptic function as a developmentally determined schizophrenia process supported by the illness's most associated genetic variants and their PPI networks. The implicated genes may be valuable targets for mechanistic experiments and future drug development approaches.

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.

Birth by Caesarean Section and the Risk of Adult Psychosis: A Population-Based Cohort Study

Despite the biological plausibility of an association between obstetric mode of delivery and psychosis in later life, studies to date have been inconclusive. We assessed the association between mode of delivery and later onset of psychosis in the offspring. A population-based cohort including data from the Swedish National Registers was used. All singleton live births between 1982 and 1995 were identified (n= 1,345,210) and followed-up to diagnosis at age 16 or later. Mode of delivery was categorized as: unassisted vaginal delivery (VD), assisted VD, elective Caesarean section (CS) (before onset of labor), and emergency CS (after onset of labor). Outcomes included any psychosis; nonaffective psychoses (including schizophrenia only) and affective psychoses (including bipolar disorder only and depression with psychosis only). Cox regression analysis was used reporting partially and fully adjusted hazard ratios (HR) with 95% confidence intervals (CI). Sibling-matched Cox regression was performed to adjust for familial confounding factors. In the fully adjusted analyses, elective CS was significantly associated with any psychosis (HR 1.13, 95% CI 1.03, 1.24). Similar findings were found for nonaffective psychoses (HR 1.13, 95% CI 0.99, 1.29) and affective psychoses (HR 1.17, 95% CI 1.05, 1.31) (χ(2)for heterogeneityP= .69). In the sibling-matched Cox regression, this association disappeared (HR 1.03, 95% CI 0.78, 1.37). No association was found between assisted VD or emergency CS and psychosis. This study found that elective CS is associated with an increase in offspring psychosis. However, the association did not persist in the sibling-matched analysis, implying the association is likely due to familial confounding by unmeasured factors such as genetics or environment.

Common or distinct pathways to psychosis? A systematic review of evidence from prospective studies for developmental risk factors and antecedents of the schizophrenia spectrum disorders and affective psychoses

BACKGROUND

Identifying the unique and shared premorbid indicators of risk for the schizophrenia spectrum disorders (SSD) and affective psychoses (AP) may refine aetiological hypotheses and inform the delivery of universal versus targeted preventive interventions. This systematic review synthesises the available evidence concerning developmental risk factors and antecedents of SSD and AP to identify those with the most robust support, and to highlight remaining evidence gaps.

METHODS

A systematic search of prospective birth, population, high-risk, and case-control cohorts was conducted in Medline and supplemented by hand searching, incorporating published studies in English with full text available. Inclusion/exclusion decisions and data extraction were completed in duplicate. Exposures included three categories of risk factors and four categories of antecedents, with case and comparison groups defined by adult psychiatric diagnosis. Effect sizes and prevalence rates were extracted, where available, and the strength of evidence synthesised and evaluated qualitatively across the study designs.

RESULTS

Of 1775 studies identified by the search, 127 provided data to the review. Individuals who develop SSD experience a diversity of subtle premorbid developmental deficits and risk exposures, spanning the prenatal period through early adolescence. Those of greatest magnitude (or observed most consistently) included obstetric complications, maternal illness during pregnancy (especially infections), other maternal physical factors, negative family emotional environment, psychopathology and psychotic symptoms, and cognitive and motor dysfunctions. Relatively less evidence has accumulated to implicate this diversity of exposures in AP, and many yet remain unexamined, with the most consistent or strongest evidence to date being for obstetric complications, psychopathology, cognitive indicators and motor dysfunction. Among the few investigations affording direct comparison between SSD and AP, larger effect sizes and a greater number of significant associations are commonly reported for SSD relative to AP.

CONCLUSIONS

Shared risk factors for SSD and AP may include obstetric complications, childhood psychopathology, cognitive markers and motor dysfunction, but the capacity to distinguish common versus distinct risk factors/antecedents for SSD and AP is limited by the scant availability of prospective data for AP, and inconsistency in replication. Further studies considering both diagnoses concurrently are needed. Nonetheless, the prevalence of the risk factors/antecedents observed in cases and controls helps demarcate potential targets for preventative interventions for these disorders.

Placental vitamin D receptor expression is decreased in human idiopathic fetal growth restriction

Fetal growth restriction (FGR) affects up to 5 % of pregnancies worldwide, and trophoblast function plays a significant role on the outcome. An epidemiological study has linked vitamin D deficiency to adverse perinatal outcomes, which include decreased birth weight. The placenta as an important source of vitamin D regulates its metabolism through the vitamin D receptor (VDR), but the mechanism by which VDR regulates trophoblast function is poorly understood. Our study aimed at determining placental VDR expression in FGR and gestation-matched control (GMC) pregnancies and identifying the actions of VDR in trophoblast differentiation and apoptosis. Placentae were collected from a well-defined cohort of idiopathic FGR and GMC pregnancies. VDR mRNA and protein expressions were determined by PCR, immunohistochemistry and immunoblotting, while functional consequences of VDR inactivation in vitro were determined on BeWo cells by determining changes in differentiation, attachment and apoptosis. Significant decreases in VDR mRNA expression (p = 0.0005) and protein expression (p = 0.0003) were observed in the FGR samples, while VDR inactivation, which showed markers for differentiation, cell attachment and apoptosis, was significantly increased. Thus, decreased placental VDR may contribute to uncontrolled premature differentiation and apoptosis of trophoblasts that are characteristics of idiopathic FGR pregnancies.

KEY MESSAGE

Fetal growth restriction (FGR) affects up to 5 % of all pregnancies worldwide. FGR is the second highest cause of perinatal mortality and morbidity. The placenta plays a pivotal role in vitamin D metabolism during pregnancy. Vitamin D deficiency is associated with adverse pregnancy outcomes. Placental vitamin D receptor expression is decreased in FGR.

Medial temporal lobe default mode functioning and hippocampal structure as vulnerability indicators for schizophrenia: a MRI study of non-psychotic adolescent first-degree relatives

BACKGROUND

Clues to the etiology and pathophysiology of schizophrenia can be examined in their first-degree relatives because they are genetically related to an ill family member, and have few confounds like medications. Brain abnormalities observed in young relatives are neurobiological indicators of vulnerability to illness. We examined the hypothesis that the hippocampus and parahippocampus are structurally abnormal and are related to default mode network (DMN) function and cognitive abnormalities in relatives of probands.

METHODS

Subjects were 27 non-psychotic, first-degree relatives of individuals diagnosed with schizophrenia, and 48 normal controls, ages 13 to 28, undergoing high-resolution magnetic resonance imaging (MRI) at 1.5 T. After structural scan acquisition a subset of subjects performed 2-back working memory (WM) and 0-back tasks during functional MRI (fMRI) alternating with rest. fMRI data were analyzed using SPM-8. Volumes of total cerebrum, hippocampus, and parahippocampal gyrus were measured using semi-automated morphometry.

RESULTS

Compared to controls, relatives had significantly smaller left hippocampi, without volumetric reduction in the parahippocampus. Relatives showed significantly less suppression of DMN activity in the left parahippocampal gyrus. Left hippocampal and posterior parahippocampal volumes were inversely and significantly associated with DMN processing (smaller volumes, less suppression) in relatives. Task suppression in parahippocampal gyrus significantly correlated with WM performance within the relatives.

CONCLUSION

Results support the hypothesis that the vulnerability to schizophrenia includes smaller hippocampi and DMN suppression deficits, and these are associated with poorer WM. Findings suggest a primary structural, neurodevelopmental, medial temporal lobe abnormality associated with altered DMN function independent of psychosis.

Altered decorin leads to disrupted endothelial cell function: a possible mechanism in the pathogenesis of fetal growth restriction?

OBJECTIVE

Fetal growth restriction (FGR) is a key cause of adverse pregnancy outcome where maternal and fetal factors are identified as contributing to this condition. Idiopathic FGR is associated with altered vascular endothelial cell functions. Decorin (DCN) has important roles in the regulation of endothelial cell functions in vascular environments. DCN expression is reduced in FGR. The objectives were to determine the functional consequences of reduced DCN in a human microvascular endothelial cell line model (HMVEC), and to determine downstream targets of DCN and their expression in primary placental microvascular endothelial cells (PLECs) from control and FGR-affected placentae.

APPROACH

Short-interference RNA was used to reduce DCN expression in HMVECs and the effect on proliferation, angiogenesis and thrombin generation was determined. A Growth Factor PCR Array was used to identify downstream targets of DCN. The expression of target genes in control and FGR PLECs was performed.

RESULTS

DCN reduction decreased proliferation and angiogenesis but increased thrombin generation with no effect on apoptosis. The array identified three targets of DCN: FGF17, IL18 and MSTN. Validation of target genes confirmed decreased expression of VEGFA, MMP9, EGFR1, IGFR1 and PLGF in HMVECs and PLECs from control and FGR pregnancies.

CONCLUSIONS

Reduction of DCN in vascular endothelial cells leads to disrupted cell functions. The targets of DCN include genes that play important roles in angiogenesis and cellular growth. Therefore, differential expression of these may contribute to the pathogenesis of FGR and disease states in other microvascular circulations.

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.

Downstream targets of the homeobox gene DLX3 are differentially expressed in the placentae of pregnancies affected by human idiopathic fetal growth restriction

Human idiopathic fetal growth restriction (FGR) is associated with placental insufficiency. Previously, we reported that the expression of homeobox gene Distal-less 3 (DLX3) is increased in idiopathic FGR placentae and is a regulator of villous trophoblast differentiation. Here, we identify the downstream targets of DLX3 in trophoblast-derived cell lines. We modelled the high levels of DLX3 in FGR using an over-expression plasmid construct and complemented this using short-interference RNA (siRNA) for inactivation in cultured cells. Using a real-time PCR-based gene profiling, candidate target genes of DLX3 over-expression and inactivation were identified as regulators of trophoblast differentiation; GATA2 and PPARγ. The expression of GATA2 and PPARγ were further assessed in placental tissues and showed increased mRNA and protein levels in FGR-affected tissues compared with gestation-matched controls. We conclude that DLX3 orchestrates the expression of multiple regulators of trophoblast differentiation and that expression of these regulatory genes is abnormal in FGR.

Neonatal MK-801 treatment differentially alters the effect of adolescent or adult MK-801 challenge on locomotion and PPI in male and female rats

Schizophrenia is a neurodevelopmental disorder and is typically "triggered" by subsequent insults in life. The N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) induces locomotor hyperactivity and prepulse inhibition (PPI) deficits, which can mimic the schizophrenia phenotype. In this experiment, we assessed whether neonatal exposure to MK-801 (postnatal days 5-14) could induce sensitization to both hyperactivity and PPI deficit caused by later-life acute MK-801 treatment during adolescence or adulthood. Our results showed that the hyperactivity induced by an acute MK-801 challenge was enhanced in male and female rats after neonatal MK-801 treatment. Notably, in the PPI test, adult female rats neonatally exposed to MK-801 exhibited a significantly greater reduction in PPI in response to acute MK-801 administration, whereas male rats receiving neonatal MK-801 treatment expressed attenuated PPI disruption in adulthood. Our data indicate that a combination of neonatal and later-life NMDA receptor blockades could induce sensitization in the locomotor activity of both sexes in adolescence and adulthood. In addition, a sex difference was observed in the effects of this treatment regime on PPI.

Interaction between parental psychosis and risk factors during pregnancy and birth for schizophrenia - the Northern Finland 1966 Birth Cohort study

Our aim was to investigate the association between parental psychosis and potential risk factors for schizophrenia and their interaction. We evaluated whether the factors during pregnancy and birth have a different effect among subjects with and without a history of parental psychosis and whether parental psychosis may even explain their effects on the risk of schizophrenia. The sample comprised 10,526 individuals from the Northern Finland 1966 Birth Cohort. A total of 150 (1.4%) cohort members had schizophrenia by the age of 44 years, of them 18 (12.0%) had a parent with a history of psychosis. In non-psychotic cohort members, this figure was 495 (4.8%). In the parental psychosis group, significant early biological risk factors for schizophrenia included high birth weight (hazard ratio, HR 11.4; 95% confidence interval 3.3-39.7) and length (HR 4.1; 1.3-12.5), high birth weight in relation to gestational age (HR 3.2; 1.1-9.0), and high maternal age (HR 2.6.; 1.0-6.7). High birth weight and length and high maternal education had a significant interaction with parental psychosis. The presence of any biological risk factor increased the risk of schizophrenia significantly only among the parental psychosis group (HR 4.0; 1.5-10.5), whereas the presence of any psychosocial risk factor had no interaction with parental psychosis. Parental psychosis can act as an effect modifier on early risk factors for schizophrenia. Evaluation of the mechanisms behind the risk factors should, therefore, include consideration of the parental history of psychosis.

Potential application as screening and drug designing tools of cytoarchitectural deficiencies present in three animal models of schizophrenia

BACKGROUND

The development of new treatment alternatives for schizophrenia has been prevented by the unknown etiology of the illness and the divergence of results in the field. However, consistent neuropathological findings are emerging from anatomical areas known to be at the core of schizophrenia. If these deficiencies are replicated in animal models then such anomalies could become the target for a new generation of drugs.

OBJECTIVE

To determine if the methylazoxymethanol acetate (MAM) model, the heterozygote reeler mouse (HRM) and NMDA-antagonists treated rats replicate neuropathological deficits encountered in patients with schizophrenia and to establish if such changes could lead the search for developing novel treatment alternatives.

METHODS

Databases including MEDLINE, Cochrane and Ovid were searched; search terms included neuropathology, schizophrenia and animal models.

RESULTS/CONCLUSIONS

NMDA-antagonist treated animals partially replicate schizophrenia anomalies in parvalbumin positive interneurons. In contrast, neuroanatomical deficiencies replicated by the MAM model and the HRM in the hippocampus and the prefrontal cortex seem promising targets for future pharmacological research in schizophrenia. Such neuroanatomical findings along with evidence from molecules and genes associated with schizophrenia suggest new drugs should aim to correct deficits in the formation of dendrites and axons that seems to be implicated in this illness pathophysiology.

A plausible model of schizophrenia must incorporate psychological and social, as well as neuro developmental, risk factors

Subtle alterations in brain development caused by genes or early environmental hazards, such as obstetric complications, play a role in projecting some individuals on a trajectory toward schizophrenia. High-risk and cohort studies demonstrate that children destined to develop schizophrenia tend to have delayed milestones and subtle neuromotor and cognitive impairments (particularly in coordination and language). These neurocognitive problems lead to difficulties in interpersonal relations, and their progressive alienation makes these at-risk children more likely to harbor odd or paranoid ideas. This cascade of increasingly deviant development may then be compounded by brain maturational changes during adolescence with a resultant lability of the dopaminergic response to stress. As a result, the individual is more susceptible to the effects of the abuse of dopamine-releasing drugs, and to other risk factors such as migration or stressful life events; social isolation may be a common pathway underlying several of the social risk factors.

Exposure to obstetric complications in relation to subsequent psychiatric disorders of adolescent inpatients: specific focus on gender differences

BACKGROUND

Exposure to obstetric complications is known to be associated with subsequent development of psychiatric disorders. However, earlier findings are mainly based on adult populations having a long follow-up time for onset of psychiatric illness. We examined whether the association of obstetric complications with severe mental disorders is already seen in a population of underage adolescents admitted to psychiatric inpatient care.

METHOD

The study population was a clinical sample of adolescents (n = 508) aged 12-17 years admitted to psychiatric hospital. DSM-IV diagnoses of the psychiatric disorders of the adolescents as well as information on obstetric (i.e., pregnancy, delivery and perinatal) complications and substance use during pregnancy reported by the mothers of the adolescents were based on the semi-structured Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime.

RESULTS

A total of 96 (19%) adolescents had been exposed to obstetric complications. The prevalence of pregnancy, delivery or perinatal complications reported by the mothers of the offspring was 55 (57%), 57 (59%) and 13 (14%), respectively. Among adolescents with conduct disorder, exposure to delivery complications was more common among males compared to females (16 vs. 5%, p = 0.006); this was particularly true for section delivery (7 vs. 1%, p = 0.023). A trend towards a significant gender difference was also found among adolescents with anxiety disorder (21 vs. 8%, p = 0.085).

CONCLUSIONS

Boys seem to be more vulnerable to the exposure of delivery complications than girls. Exposure to obstetric complication may be associated with development of subsequent psychiatric disorder; particularly conduct disorder of adolescent boys.

Placental syndecan expression is altered in human idiopathic fetal growth restriction

Pregnancy represents a hypercoagulable state characterized by increased thrombin generation. However, placentas from fetal growth restriction (FGR) pregnancies are characterized by increased fibrin deposition and thrombi in the vasculature, indicative of a further increase in thrombin activation and a disturbance in coagulation in this clinical setting. The cause of the coagulation disturbance observed in FGR pregnancies is currently unknown. Anticoagulant mechanisms are crucial in the regulation of thrombin activity, and current evidence suggests that syndecans are the principal placental anticoagulant proteoglycans. The aim of this study was to determine the localization, distribution, and expression of syndecans 1 to 4 in placentas complicated by idiopathic FGR compared with gestation-matched controls. Immunohistochemistry results revealed that all of the syndecans were localized to cells located closely to the maternal and fetal circulation. The mRNA and protein expression levels of both syndecan 1 and syndecan 2 were significantly decreased in FGR samples compared with controls. This is the first study to demonstrate the differential expression of syndecans 1 to 4 in idiopathic FGR placentas compared with controls. Reduced levels of syndecan expression may result in increased placental thrombosis in the uteroplacental circulation and may therefore contribute to the pathogenesis of FGR.

Perinatal complications in unaffected sisters of anorexia nervosa patients: testing a covariation model between genetic and environmental factors

Although perinatal complications are hypothesized to be risk factors for the development of anorexia nervosa (AN), no study to date explored this issue using a discordant sibling design. This type of design allows to explore whether the risk for obstetric complications is itself a consequence of the genetic vulnerability for AN (covariation model) or whether obstetric complications increase the risk of AN independently of (additive model), or in interaction with (interaction model), the disorder's genetic liability. The presence of perinatal complications was assessed through review of the obstetric records of 60 AN subjects, 60 unaffected sisters, and 70 healthy subjects. Unaffected sisters and healthy controls were compared in relation to perinatal characteristics and complications. There was no evidence for an elevated rate of complications in unaffected siblings of AN patients. Mothers with a positive psychiatric history tended to have more perinatal complications. Perinatal complications seem to be independent risk factors that may interact with, but are not caused by, familial risk factors for AN. In terms of prevention, a particular attention should be paid to mothers with a lifetime history of psychiatric disorders.

Schizophrenia, cancer and obstetric complications in an evolutionary perspective-an empirically based hypothesis

OBJECTIVE

Patients diagnosed with schizophrenia have reduced fecundity and premature mortality (both accidental and violent) with no obvious compensatory advantages among kin. The prevalence of the disorder is around 0.7/1%, higher than the expected prevalence of spontaneous mutations. Genes favoring schizophrenia may have been positively selected in the environment of evolutionary adaptation. Literature on potential adaptive genes is reviewed within an evolutionary framework.

METHODS

Literature search on major scientific search engine (PubMed/Medline, Ovid/PsychInfo) on papers aimed at investigating potential pathways justifying a mutation-selection balanced model. Findings are presented with a narrative touch to favor readability and understanding.

RESULTS

Reduced incidence of cancer in both patients diagnosed with schizophrenia and their siblings was reported worldwide. Such findings are notable given higher cancer risk factors in schizophrenia, i.e., smoking, alcohol abuse, obesity, poor diet, and poor adherence to therapy. Some genes involved in cancer proliferation might as well confer protective advantage in immune-surveillance, inflammation, vascular proliferation or apoptosis that otherwise will adversely affect early neurodevelopment.

CONCLUSION

Evidence that reduced risk of certain somatic diseases is associated with schizophrenia is quite significant to progress in the evolutionary epidemiological analysis of psychopathology.

Familial liability, obstetric complications and childhood development abnormalities in early onset schizophrenia: a case control study

BACKGROUND

Genetic and environmental risk factors and gene-environment interactions are linked to higher likelihood of developing schizophrenia in accordance with the neurodevelopmental model of disease; little is known about risk factors and early development in early-onset schizophrenia (EOS) and very early-onset schizophrenia (VEOS).

METHODS

We present a case-control study of a sample of 21 patients with EOS/VEOS and a control group of 21 patients with migraine, recruited from the Child Neuropsychiatry Unit, Department of Neurologic and Psychiatric Science, University of Bari, Italy. The aim was to assess the statistical association between VEOS/EOS and family history for psychiatric disorders, obstetric complications and childhood developmental abnormalities using 2 × 2 tables and a Chi Squared or Fisher test.

RESULTS

The results show a statistical association between EOS/VEOS and schizophrenia and related disorders (P = 0.02) and personality disorders (P = 0.003) in relatives, and between EOS/VEOS and developmental abnormalities of early relational skills (P = 0.008) and learning (P = 0.04); there is not a statistically relevant difference between cases and controls (P > 0.05) for any obstetric complications (pre, peri and postpartum).

CONCLUSIONS

This study confirms the significant role of familial liability but not of obstetric complications in the pathogenesis of VEOS/EOS; the association between childhood developmental abnormalities and EOS/VEOS supports the neurodevelopmental model of disease.

Deviant intrauterine growth and risk of schizophrenia: a 34-year follow-up of the Northern Finland 1966 Birth Cohort

BACKGROUND

Low birth weight conveys a modest risk for schizophrenia. The effects of high birth weight and deviant birth length are less clear.

METHODS

We linked perinatal data from 10,934 subjects from the Northern Finland 1966 Birth Cohort (n = 12 058) to the Finnish Hospital Discharge Register where we identified 111 cases of DSM-III-R schizophrenia up to age 35 years. Adjusted odds ratios between the risk of schizophrenia and birth weight, birth length and ponderal index and the risk of schizophrenia were analyzed.

RESULTS

Both low (OR 2.5; 95% CI 1.2-5.1) and high birth weight (OR 2.4; 95% CI 1.1-4.9) increased the risk of later schizophrenia. In addition, short (OR 2.6; 95% CI 1.1-5.9) and long babies had an elevated risk of schizophrenia as adults (OR 1.8; 95% CI 1.0-3.5). A reverse J-shape curve described the associations between birth weight, length and schizophrenia.

CONCLUSIONS

Deviant intrauterine growth of the fetus in either direction was associated with increased risk of schizophrenia.

Downstream targets of homeobox gene HLX show altered expression in human idiopathic fetal growth restriction

Fetal growth restriction (FGR), a clinically significant pregnancy disorder, is poorly understood at the molecular level. This study investigates idiopathic FGR associated with placental insufficiency. Previously, we showed that the homeobox gene HLX is expressed in placental trophoblast cells and that HLX expression is significantly decreased in human idiopathic FGR. Here, we used the novel approach of identifying downstream targets of HLX in cell culture to detect potentially important genes involved in idiopathic FGR. Downstream targets were revealed by decreasing HLX expression in cultured trophoblast cells with HLX-specific small interfering RNAs to model human idiopathic FGR and comparing these levels with controls using a real-time PCR-based gene profiling system. Changes in candidate HLX target mRNA levels were verified in an independent trophoblast cell line, and candidate target gene expression was assessed in human idiopathic FGR-affected placentae (n = 25) compared with gestation-matched controls (n = 25). The downstream targets RB1 and MYC, cell cycle regulatory genes, showed significantly increased mRNA levels in FGR-affected tissues compared with gestation-matched controls, whereas CCNB1, ELK1, JUN, and CDKN1 showed significantly decreased mRNA levels (n = 25, P < 0.001, t-test). The changes for RB1 and CDKN1C were verified by Western blot analysis in FGR-affected placentae compared with gestation-matched controls (n = 6). We conclude that cell cycle regulatory genes RB1, MYC, CCNB1, ELK1, JUN, and CDKN1C, which control important trophoblast cell functions, are targets of HLX.

Dissociation of long-term verbal memory and fronto-executive impairment in first-episode psychosis

BACKGROUND

Verbal memory is frequently and severely affected in schizophrenia and has been implicated as a mediator of poor clinical outcome. Whereas encoding deficits are well demonstrated, it is unclear whether retention is impaired. This distinction is important because accelerated forgetting implies impaired consolidation attributable to medial temporal lobe (MTL) dysfunction whereas impaired encoding and retrieval implicates involvement of prefrontal cortex.

METHOD

We assessed a group of healthy volunteers (n=97) and pre-morbid IQ- and sex-matched first-episode psychosis patients (n=97), the majority of whom developed schizophrenia. We compared performance of verbal learning and recall with measures of visuospatial working memory, planning and attentional set-shifting, and also current IQ.

RESULTS

All measures of performance, including verbal memory retention, a memory savings score that accounted for learning impairments, were significantly impaired in the schizophrenia group. The difference between groups for delayed recall remained even after the influence of learning and recall was accounted for. Factor analyses showed that, in patients, all variables except verbal memory retention loaded on a single factor, whereas in controls verbal memory and fronto-executive measures were separable.

CONCLUSIONS

The results suggest that IQ, executive function and verbal learning deficits in schizophrenia may reflect a common abnormality of information processing in prefrontal cortex rather than specific impairments in different cognitive domains. Verbal memory retention impairments, however, may have a different aetiology.

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.

Altered growth factor signaling pathways as the basis of aberrant stem cell maturation in schizophrenia

In recent years evidence has accumulated that the activity of the signaling cascades of Neuregulin-1, Wnt, TGF-beta, BDNF-p75 and DISC1 is different between control subjects and patients with schizophrenia. These pathways are involved in embryonic and adult neurogenesis and neuronal maturation. A review of the clinical data indicates that in schizophrenia the Wnt pathway is most likely hypoactive, whereas the Nrg1-ErbB4, the TGF-beta- and the BDNF-p75-pathways are hyperactive. Haplo-insuffiency of the DISC1 gene is currently the best established schizophrenia risk factor. Preclinical experiments indicate that suppression of DISC1 signaling leads to accelerated dendrite development in neuronal stem cells, accelerated migration and aberrant integration into the neuronal network. Other preclinical experiments show that increasing NRG1-, BDNF- and TGF-beta signaling and decreasing Wnt signaling, also promotes adult neuronal differentiation and migration. Thus deviations in these pathways detected in schizophrenia could contribute to premature neuronal differentiation, accelerated migration and inappropriate insertion into the neuronal network. Initial clinical findings are confirmatory: neuronal stem cells isolated from nasal biopsies from schizophrenia patients display signs of accelerated development, whilst increased erosion of telomeres and bone age provide further support for accelerated cell maturation in schizophrenia.