Winter birth excess in schizophrenia and in non-schizophrenic psychosis: Sex and birth-cohort differences (original) (raw)
Related papers
Seasonality of birth in schizophrenia: the effect of regional population density
Schizophrenia …, 1997
It has been suggested that winter birth in urban areas may be associated with an increased risk of schizophrenia. Data on 4139 patients with a hospital diagnosis of schizophrenia were obtained from a survey of public departments of psychiatry in metropolitan France. Place of birth was classified according to the administrative subdivision of French territory into 95 ‘départements’. Density of population in the decade and in the département of birth was identified using successive census data. A 20% excess (OR, 1.20; 95% CI, 1.03–1.40; p = 0.02) of winter births (January–March) was found among patients born in highly densely populated areas (> 136 inhabitants/km2) compared to those born in other areas. These results suggest that seasonal early environmental risk factor(s) linked to schizophrenia predominantly operate in urban areas.
Season of birth and schizophrenia: Sex difference
Progress in Neuro-Psychopharmacology and Biological Psychiatry, 1996
A statistically significant increased risk of schizophrenia for individuals born in winter has been reported. The increase risk is of the order of S-1 5%. The seasonal effect is more marked among females. This winter birth effect suggests some environmental agents, probably a neuropathogen one, acting on the foetus. The present study sought to test the environmental damage hypothesis by application of the family history of psychiatric disorder distinction to season of birth data divided according to sex and using a control population. From computer records, all patients admitted to the psychiatric department of Marseilles Timone hospital between January 1984 and December 1989 who satisfied DSM III , DSM III R criteria for schizophrenia were identified. Patients were then classified into two groups : family history of psychiatric disorder versus no family history. Division according to the sex was carried on after two groups were formed. The data show (1) a significant excess of births in the early months of the year (p < 0.05) for all patients with no family history of psychiatric disorder, (7) a significant excess of births for females (p < 0.05) with no family history. These results provide indirect support for the neurodevelopmental theory of schizophrenia.
Psychiatry Research, 1996
Birth in late winter and spring has been consistently shown to be a risk factor of schizophrenia. The relationship of late winter/spring birth to clinical characteristics and other putative risk factors, such as family history and obstetric complications, may provide clues to etiology. Data relating to season of birth, clinical features, family history, and obstetric complications were analyzed for 19'2 patients with schizophrenia as defined by Research Diagnostic Criteria (including schizoaffective disorder). There was no significant association of season of birth with any of the psychopathological dimensions nor was there a significant association with obstetric variables or family history. However, winter-born schizophrenic patients who had a negative family history were more likely to have a history of obstetric complications. These findings suggest that obstetric complications associated with schizophrenia are perhaps the result of some seasonal risk factors important in those without a family history of the disorder.
Season of birth in schizophrenia: no latitude at the equator
The British Journal of Psychiatry, 2000
If the established winter excess in births of people who subsequently develop schizophrenia is an effect of &amp;#39;seasonality&amp;#39;, this would be testable by examining the pattern of births in an equatorial region with no formal seasons. To investigate whether there is any variation in month of birth among patients from equatorial Singapore with a diagnosis of schizophrenia. All 9655 patients discharged from Singapore&amp;#39;s national psychiatric hospital with a diagnosis of schizophrenia were included (year of birth range 1930-1984). We analysed aggregated data, as well as the data of subsamples grouped according to birth-year periods, in order to examine secular trends. One patient subsample (those born 1960-84) allowed exact matching against the general population data set and close testing of any seasonal influence. Monthly variation in births was evident for both patients and controls; the patterns were very similar, apart from the patient sample showing a trough in March-April. In an equatorial region, where &amp;#39;seasons&amp;#39; are absent, no seasonal excess in births of those later developing schizophrenia was evident.
Summer Birth and Deficit Schizophrenia
Archives of General Psychiatry, 2004
Background: In some reports, summer birth has been associated with deficit schizophrenia. Deficit schizophrenia and nondeficit schizophrenia also differ in several other ways.
Excess Seasonality of Births Among Patients With Schizophrenia and Seasonal Ovopathy
Schizophrenia Bulletin, 1994
In this study we examined whether the well-known winter excess of schizophrenic births exists among Dutch schizophrenia patients when statistical artifacts such as the age-incidence and age-prevalence effects are avoided and, if so, whether the seasonal preovulatory release of overripe ovum (SPrOO) hypothesis, that is, seasonally bound ovopathy, might be an explanation for this excess. We analyzed the month-of-birth distribution of 1,037 Dutch schizophrenia patients born between 1962 and 1966 and first admitted to a psychiatric hospital between 1978 and 1990 by the so-called window analysis to avoid the artifacts mentioned. The results show a winter excess of births among Dutch schizophrenia patients, even when statistical artifacts are avoided, and that the SPrOO hypothesis might be an explanation for this excess. Further research is needed to support the hypothesis that ovopathy, either seasonally bound or not, could be involved in the etiology of schizophrenia. Schizophrenia Bulletin, 20(2): 269-276, 1994.
American Journal of Psychiatry, 2001
Objective: The birth rate of patients with schizophrenia during the winter and spring months is 5%-8% higher worldwide than the birth rate of the general population in the winter and spring months. Seasonal variation of births among the unaffected siblings of patients with schizophrenia has not been studied with adequate sample sizes. The authors investigated the seasonal variation of births among siblings of patients with schizophrenia in a large, nationwide, representative patient and sibling population. Method: Finnish patients with schizophrenia born from 1950 to 1969 (N= 15,389) were identified from three nationwide health care registers. Unaffected siblings of these patients born in the same time period (N=37,819) were identified from the Finnish National Population Register. The seasonal variation of births among patients and siblings were examined by using a log-linear model. Explanatory variables were sex, year of birth categorized into four 5-year groups, and seasonal variation, which was analyzed by fitting a short Fourier series to the monthly birth data. Results: The odds for having been born during the winter-spring months were slightly higher among both siblings and patients in all birth-year groups. However, patients born from 1955 to 1959 showed prominent seasonal variation of births, but the magnitude of this variation remained unchanged among siblings.