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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epidemiological evidence that the offspring of women exposed to influenza in pregnancy are at increased risk of schizophrenia is conflicting. In an attempt to clarify the issue we explored the relationship between the monthly incidence of influenza (and measles) in the general population and the distribution of birth dates of three large series of schizophrenia patients--16,960 Scottish patients born in 1932-60; 22,021 English patients born in 1921-60; and 18,723 Danish patients born in 1911-65. Exposure to the 1957 epidemic of A2 influenza in midpregnancy was associated with an increased incidence of schizophrenia, at least in females, in all three data sets. We also confirmed the previous report of a statistically significant long-term relationship between patients' birth dates and outbreaks of influenza in the English series, with time lags of -2 and -3 months (the sixth and seventh months of pregnancy). Despite several other negative studies by ourselves and others we conclude that these relationships are probably both genuine and causal; and that maternal influenza during the middle third of intrauterine development, or something closely associated with it, is implicated in the aetiology of some cases of schizophrenia.
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PMID:Epidemiological evidence that maternal influenza contributes to the aetiology of schizophrenia. An analysis of Scottish, English, and Danish data. 825 93

The question of whether prenatal exposure to influenza epidemics is associated with an increased risk of later schizophrenia remains controversial. The authors examined this relationship, using data on the dates of birth and gender of 3,827 schizophrenic patients born in England and Wales between 1938 and 1965 and first admitted to hospitals in the 1980s, the numbers of live births between 1938 and 1965, and the numbers of deaths attributed to influenza between 1937 and 1965. The analysis showed that females, but not males, exposed to influenza epidemics 5 months before birth had a significantly greater rate of adult schizophrenia.
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PMID:Prenatal exposure to influenza and the development of schizophrenia: is the effect confined to females? 780 10

Recent reports that some influenza epidemics may be followed by a transient increase in the births of schizophrenic patients have led to the hypothesis that maternal viral infections contribute to the aetiology of schizophrenia. It is well known that respiratory viral infections are frequently brought into the home by young children. We tested the predictions that the risk of schizophrenia is decreased in first-born children, and increased in individuals who had siblings of a young age while in utero, using data from a Swedish family study. Our results are consistent with these predictions. In particular, having siblings three to four years older was associated with a significantly increased risk of schizophrenia, even after allowing for birth order, sibship size, and other potential confounders. If replicated, these results provide indirect support for the maternal viral infection hypothesis, although there are alternative explanations.
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PMID:Risk of schizophrenia and age difference with older siblings. Evidence for a maternal viral infection hypothesis? 829 31

Thirty years ago, Eliot Slater suggested that the reason schizophrenia was not progressively eliminated from the population was that the responsible gene also conveyed a compensatory advantage in terms of increased resistance to infection. If this selective advantage lies in the antibody response to certain viral infections, this could explain recent studies suggesting that exposure to influenza in the second trimester of gestation increases the risk of later schizophrenia. We propose that prenatal exposure to influenza induces maternal antibodies which then cross-react with proteins in the developing foetal brain, becoming foetal autoantibodies. Thus an immunogenetic response by the mother results in aberrant foetal neurodevelopment, the biological substrate for a proportion of adult schizophrenia. Initial research strategies to test this hypothesis are proposed.
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PMID:Schizophrenia: genetics and the maternal immune response to viral infection. 835 35

Mednick et al and O'Callaghan et al have recently reported that individuals exposed to the 1957 A2 influenza pandemic during their second trimester in utero are at risk for later schizophrenia. In this study, we determined whether their findings could be reproducible in a Japanese sample. In Japan, there were two waves of the 1957 A2 influenza pandemic; the first occurred from June to July, and the second from November to December. In addition, an epidemic of influenza A/B mixed type prevailed from January to February 1957. We obtained information on all dates of birth of 1187 individuals born between June 1955 and May 1960, who were treated for schizophrenia during the study period. November 1991 to September 1992, at 18 mental hospitals around Tokyo metropolitan areas. Hospital clinical diagnosis was used. We defined the index year from June 1957, beginning the first wave of the pandemic, to May 1958. We compared the number of schizophrenic births in each month of the index year with the average number of births in the corresponding month of the two years before, and following, the index year. The observed number of births in June 1957 and April 1958 were found to be significantly high compared with the average number of births for the corresponding month in the four control years. The 63% excess of schizophrenic births in June 1957 ensued about 5 months after the peak of influenza A/B mixed type epidemic; there was also 49% increase in births about 5 months after the second wave of the pandemic. Given that full term delivery occurred in our sample (ie, 9 months pregnancy), our results support the view of Mednick et al and O'Callaghan et al that maternal exposure to influenza in the mid-pregnancy increases the risk of developing schizophrenia.
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PMID:[Schizophrenia following prenatal exposure to influenza during second trimester]. 837 58

The role of aberrant neurodevelopment in the etiology of schizophrenia is reviewed in light of recent neuropathologic, neurochemical, and neuroimaging evidence of cerebral abnormalities in schizophrenic patients. There may exist some genetic defect in the control of brain development. Clinical epidemiologic surveys highlight the importance of obstetric complications, and prenatal exposure to influenza epidemics in contributing to these abnormalities. It is suggested that such environmental hazards and aberrations in the control of early brain development produce the neuronal phenotype that manifests as schizophrenia with early age of onset of symptoms associated with soft neurologic signs and is more common in young males.
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PMID:Schizophrenia: a neurodevelopmental perspective. 839 27

We investigated any effect of prenatal exposure to influenza during gestation on subsequent risk of schizophrenia using a national sample from The Netherlands. Dates of births of all Dutch-born schizophrenia (ICD-9) patients (n = 10,630) admitted to hospitals for the first time between 1970 and 1992 were examined in relation to the occurrence of influenza epidemics between 1947 and 1969. As a measure of prevalence of influenza, the number of deaths from influenza per month in The Netherlands was used. A Poisson regression analysis revealed that an increase in the prevalence of influenza 3 months prior to birth was followed by an increase in births of preschizophrenics, although this fell outside statistical significance (p = .11). However, the effect became marked in typical schizophrenics (n = 4726), but not in less typical cases (n = 5389). For typical schizophrenics, the parameter estimate derived from the regression model indicates that there was a 10% increase (95% confidence interval: -1 to 22%) in preschizophrenic births for every 500 deaths from influenza 3 months before birth.
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PMID:Maternal exposure to influenza and risk of schizophrenia: a 22 year study from The Netherlands. 864 41

A topic of current controversy is that maternal exposure to influenza in the 2nd trimester of pregnancy may place the offspring at increased risk for schizophrenia. However, exposure to cold and to influenza may be confounded in existing studies, and case finding and identification may introduce error. Use of measures of schizotypy that are dimensional may be used to overcome some of the difficulties of case identification. Data are derived from the longitudinal study in Mauritius, an island in the southern hemisphere, where, in the case of the 1968-1972 Hong Kong/A2 influenza virus epidemic, influenza and low temperature were not confounded. The results suggest that women's exposure to influenza in pregnancy is associated with an elevation of positive schizotypy scores, whereas exposure to low environmental temperatures is associated with an elevation of anhedonia scores in their offspring.
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PMID:Schizotypy and maternal exposure to influenza and to cold temperature: the Mauritius study. 866 11

Several epidemiological studies have suggested that maternal exposure to influenza during midgestation is a risk factor for schizophrenia. In exploring the possible pathogenic mechanism, we examined the relationship between computed tomography structural brain measures in 83 schizophrenia patients and 113 controls and also their risk of maternal exposure to influenza. Four brain measures of the cerebrospinal fluid (CSF) spaces (lateral ventricle, maximum third ventricle, sulcal fluid, and sylvian fissure) were investigated in relation to the risk exposure level. In schizophrenia patients, these measures, in particular sylvian fissures, were found to increase with higher levels of risk exposure to influenza during the susceptible period (i.e., midgestation); no such effect was found in controls. These results indicate that risk for midgestational influenza exposure is associated with generalized enlargement of the CSF spaces, especially in the region of the temporal lobe. The findings suggest that certain morphological abnormalities of the brain frequently reported in schizophrenia patients may be partly attributable to antenatal exposure to influenza.
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PMID:Prenatal exposure to influenza and increased cerebrospinal fluid spaces in schizophrenia. 887 2

Several recent epidemiological studies suggest that exposure to influenza during gestation increases the risk of later developing schizophrenia. Inconsistency exists, however, particularly in studies that have examined the relationship between the prevalence of influenza and the monthly number of schizophrenic births, over many years. Our sample (N = 9462) was obtained from a Danish computerized case register, and consisted of schizophrenia patients born between 1915 and 1970, and first admitted to Danish psychiatric hospitals between 1971 and 1991. The study sample was chosen to represent "incidence cases" to allow us to calculate the population attributable risk fraction (PAF). The temporal correlation of fluctuations in the prevalence of influenza and fluctuations in the monthly number of preschizophrenic births was examined using a Poisson regression analysis. Exposure to influenza 4 months prior to birth (i.e., about the 6th month of gestation) was significantly associated with an increased risk of later schizophrenia, especially for narrowly defined schizophrenia. The number of schizophrenic births was found to have risen by 12% (95% confidence interval: 1-24%) for every 100,000 cases of influenza in the 4th month before birth. Our model indicates the PAF to be 1.4%, that is, only 1.4% of the whole schizophrenic sample is attributed to prenatal exposure to influenza. Although maternal exposure to influenza during midgestation is not a major risk factor for schizophrenia, the elucidation of its causal mechanism may open the avenue to understanding the neurodevelopmental origins of the disease.
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PMID:Relationship between in utero exposure to influenza epidemics and risk of schizophrenia in Denmark. 889 67


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