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BackgroundFamily history is a long-standing and readily obtainable risk factor for schizophrenia (SCZ). Low-cost genotyping technologies have enabled large genetic studies of SCZ, and the results suggest the utility of genetic risk scores (GRS, direct assessments of inherited common variant risk). Few studies have evaluated family history and GRS simultaneously to ask whether one can explain away the other.MethodsWe studied 5959 SCZ cases and 8717 controls from four Nordic countries. All subjects had family history data from national registers and genome-wide genotypes that were processed through the quality control procedures used by the Psychiatric Genomics Consortium. Using external training data, GRS were estimated for SCZ, bipolar disorder (BIP), major depression, autism, educational attainment, and body mass index. Multivariable modeling was used to estimate effect sizes.ResultsUsing harmonized genomic and national register data from Denmark, Estonia, Norway, and Sweden, we confirmed that family history of SCZ and GRS for SCZ and BIP were risk factors for SCZ. In a joint model, the effects of GRS for SCZ and BIP were essentially unchanged, and the effect of family history was attenuated but remained significant. The predictive capacity of a model including GRS and family history neared the minimum for clinical utility.ConclusionsCombining national register data with measured genetic risk factors represents an important investigative approach for psychotic disorders. Our findings suggest the potential clinical utility of combining GRS and family history for early prediction and diagnostic improvements. [ABSTRACT FROM AUTHOR]

BackgroundAdvancing paternal age has been linked to psychiatric disorders. These associations might be caused by the increased number of de novo mutations transmitted to offspring of older men. It has also been suggested that the associations are confounded by a genetic liability for psychiatric disorders in parents. The aim of this study was to indirectly test the confounding hypotheses by examining if there is a genetic component to advancing paternal age and if men with a genetic liability for psychiatric disorders have children at older ages.MethodWe examined the genetic component to advancing paternal age by utilizing the twin model in a cohort of male twins (N = 14 679). We also studied ages at childbirth in men with or without schizophrenia, bipolar disorder and/or autism spectrum disorder. Ages were examined in: (1) healthy men, (2) affected men, (3) healthy men with an affected sibling, (4) men with healthy spouses, (5) men with affected spouses, and (6) men with healthy spouses with an affected sibling.ResultsThe twin analyses showed that late fatherhood is under genetic influence (heritability = 0.33). However, affected men or men with affected spouses did not have children at older ages. The same was found for healthy individuals with affected siblings. Instead, these men were generally having children at younger ages.ConclusionAlthough there is a genetic component influencing late fatherhood, our data suggest that the associations are not explained by psychiatric disorders or a genetic liability for psychiatric disorders in the parent. [ABSTRACT FROM PUBLISHER]

BackgroundImpulsivity is associated with bipolar disorder as a clinical feature during and between manic episodes and is considered a potential endophenotype for the disorder. Schizophrenia and major depressive disorder share substantial genetic overlap with bipolar disorder, and these two disorders have also been associated with elevations in impulsivity. However, little is known about the degree of overlap among these disorders in discrete subfacets of impulsivity and whether any overlap is purely phenotypic or due to shared genetic diathesis.MethodWe focused on five subfacets of impulsivity: self-reported attentional, motor, and non-planning impulsivity, self-reported sensation seeking, and a behavioral measure of motor inhibition (stop signal reaction time; SSRT). We examined these facets within and across disorder proband and co-twin groups, modeled heritability, and tested for endophenotypic patterning in a sample of twin pairs recruited from the Swedish Twin Registry (N = 420).ResultsWe found evidence of moderate to high levels of heritability for all five subfacets. All three proband groups and their unaffected co-twins showed elevations on attentional, motor, and non-planning impulsivity. Schizophrenia probands (but not their co-twins) showed significantly lower sensation seeking, and schizophrenia and bipolar disorder probands (but not in their co-twins) had significantly longer SSRTs, compared with healthy controls and the other groups.ConclusionsAttentional, motor, and non-planning impulsivity emerged as potential shared endophenotypes for the three disorders, whereas sensation seeking and SSRT were associated with phenotypic affection but not genetic loading for these disorders. [ABSTRACT FROM PUBLISHER]

BackgroundPreconception, prenatal and postnatal maternal stress is associated with increased offspring psychopathology, but findings are inconsistent and need replication. We estimated associations between maternal bereavement stress and offspring autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), bipolar disorder, schizophrenia, suicide attempt and completed suicide.MethodUsing Swedish registers, we conducted the largest population-based study to date examining associations between stress exposure in 738 144 offspring born 1992–2000 for childhood outcomes and 2 155 221 offspring born 1973–1997 for adult outcomes with follow-up to 2009. Maternal stress was defined as death of a first-degree relative during (a) the 6 months before conception, (b) pregnancy or (c) the first two postnatal years. Cox proportional survival analyses were used to obtain hazard ratios (HRs) in unadjusted and adjusted analyses.ResultsMarginal increased risk of bipolar disorder and schizophrenia following preconception bereavement stress was not significant. Third-trimester prenatal stress increased the risk of ASD [adjusted HR (aHR) 1.58, 95% confidence interval (CI) 1.15–2.17] and ADHD (aHR 1.31, 95% CI 1.04–1.66). First postnatal year stress increased the risk of offspring suicide attempt (aHR 1.13, 95% CI 1.02–1.25) and completed suicide (aHR 1.51, 95% CI 1.08–2.11). Bereavement stress during the second postnatal year increased the risk of ASD (aHR 1.30, 95% CI 1.09–1.55).ConclusionsFurther research is needed regarding associations between preconception stress and psychopathological outcomes. Prenatal bereavement stress increases the risk of offspring ASD and ADHD. Postnatal bereavement stress moderately increases the risk of offspring suicide attempt, completed suicide and ASD. Smaller previous studies may have overestimated associations between early stress and psychopathological outcomes. [ABSTRACT FROM AUTHOR]

BackgroundOffspring of patients with schizophrenia exhibit poorer school performance compared with offspring of non-schizophrenic parents. We aimed to elucidate the mechanisms behind this association.MethodWe linked longitudinal national population registers in Sweden and compared school performance among offspring of schizophrenic parents with offspring of non-schizophrenic parents (1 439 215 individuals with final grades from compulsory school 1988–2006). To investigate the mechanisms, we studied offspring of schizophrenic patients and controls within the same extended families. We investigated genetic effects by stratifying analyses of parent–child associations according to genetic relatedness (half-cousins, full cousins and half-siblings). Environmental effects were investigated by comparing school performance of offspring of schizophrenic fathers and of schizophrenic mothers, respectively, and by stratifying the analyses according to environmental relatedness while controlling genetic relatedness (paternal and maternal half-cousins, paternal and maternal half-siblings).ResultsOffspring of parents with schizophrenia had poorer overall school performance than unrelated offspring of non-schizophrenic parents (−0.31 s.d.). Variability in genetic relatedness greatly moderated the strength of the within-family association (β=−0.23 within exposure-discordant half-cousins, β=−0.13 within exposure-discordant full cousins, β=0.04 within exposure-discordant half-siblings), while no evidence was found that the environment affected offspring school performance.ConclusionsGenetic factors account for poorer school performance in children of parents with schizophrenia. This supports that cognitive deficits found in individuals with schizophrenia and their relatives might be genetically inherited. Early detection of prodromal signs and impaired functioning of offspring of patients with schizophrenia could lead to earlier and better tailored interventions. [ABSTRACT FROM PUBLISHER]

BackgroundThere is abundant evidence that schizophrenia is associated with cognitive deficits in childhood. However, previous studies investigating school performance have been inconclusive. Furthermore, there are several biological and social factors that could confound the association. We investigated whether school performance at age 16 is associated with risk of adult schizophrenia and other psychoses in a large national cohort, while controlling for multiple confounders.MethodUsing a national sample of 907 011 individuals born in Sweden between 1973 and 1983, we used Cox regression to assess whether scholastic achievement at age 15?16 predicted hospital admission for psychosis between ages 17 and 31, adjusting for potential confounders.ResultsPoor school performance was associated with increased rates of schizophrenia [hazard ratio (HR) 3.9, 95% confidence interval (CI) 2.8?5.3], schizo-affective disorder (HR 4.2, 95% CI 1.9?9.1) and other psychoses (HR 3.0, 95% CI 2.3?4.0). Receiving the lowest (E) grade was significantly associated with risk for schizophrenia and other psychoses in every school subject. There was no evidence of confounding by migrant status, low birthweight, hypoxia, parental education level or socio-economic group.ConclusionsPoor school performance across all domains is strongly associated with risk for schizophrenia and other psychoses. [ABSTRACT FROM AUTHOR]

Background: The present study examines the effects of independent, single pre- and perinatal risk factors and rates of obstetric complications upon the subsequent development of schizophrenia.Method: This study was based on prospectively recorded birth records of 107 cases (82 with schizophrenic disorders and 25 with other psychotic reactions) and 214 controls, individually matched by gender and time and place of birth. Variables univariately associated with significantly elevated risk were entered in a logistic regression model.Results: A high non-optimality summary score (> or = 7 complications of 34 possible) was a significant risk estimate for the total index group (OR 4.58, 95% CI 1.74-12.03) and the 82 schizophrenic patients (OR 3.67, CI 1.30-10.36). Patients with 2-6 complications also had an increased, although lower, risk (OR 1.67, CI 1.02-2.75). A disproportionate birth weight for body length (OR 3.57, CI 1.77-7.19) and a small head circumference (OR 3.93, CI 1.32-11.71) were the strongest independent risk factors.Conclusions: A contribution of obstetric complications to the risk of schizophrenia was confirmed. Only aberrations in physical size remained as individual independent risk factors. [ABSTRACT FROM AUTHOR]

Background: Patients with schizophrenia suffer from a broad range of cognitive disturbances. The impact in terms of functional outcome is significant. There are also several reports of disturbed autonomic regulation in the disease. The present study examined cognitive function as well as psychophysiological parameters in patients with schizophrenia and healthy controls., Methods: Twenty-five patients and 14 controls were investigated with electrodermal activity (EDA), an oral niacin skin flush test and a comprehensive neurocognitive test program including the Wechsler battery (WAIS-R), Fingertapping Test, Trail Making Test, Verbal Fluency, Benton Visual Retention Test, Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test., Results: The patients generally had inferior test results compared to controls. Further analysis revealed that the EDA non-responding patient group explained this variation with significant lower test results than controls. On executive tests, EDA non-responders also performed significantly worse than EDA responding patients. The small group of niacin non-responding patients exhibited an even lower overall test performance. Delayed niacin flush also correlated inversely with psychomotor function and IQ in the patients., Conclusion: The findings support the hypothesis of a neurodevelopment disturbance affecting both autonomic function and higher cortical function in schizophrenia., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: There is a long-standing belief that creativity is coupled with psychopathology., Aims: To test this alleged association and to investigate whether any such association is the result of environmental or genetic factors., Method: We performed a nested case-control study based on Swedish registries. The likelihood of holding a creative occupation in individuals who had received in-patient treatment for schizophrenia, bipolar disorder or unipolar depression between 1973 and 2003 and their relatives without such a diagnosis was compared with that of controls., Results: Individuals with bipolar disorder and healthy siblings of people with schizophrenia or bipolar disorder were overrepresented in creative professions. People with schizophrenia had no increased rate of overall creative professions compared with controls, but an increased rate in the subgroup of artistic occupations. Neither individuals with unipolar depression nor their siblings differed from controls regarding creative professions., Conclusions: A familial cosegregation of both schizophrenia and bipolar disorder with creativity is suggested.