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Crawford L, Loprinzi PD. Effects of Exercise on Memory Interference in Neuropsychiatric Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1228:425-438. [PMID: 32342475 DOI: 10.1007/978-981-15-1792-1_29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
There are several mechanisms that cause memory impairment, including motivated forgetting, active forgetting, natural decay, and memory interference. Interference occurs when one is attempting to recall something specific, but there is conflicting information making it more difficult to recall the target stimuli. In laboratory settings, it is common to measure memory interference with paired associate tasks-usually utilizing the AB-CD, AB-AC, AB-ABr, or AB-DE AC-FG method. Memory impairments are frequent among those with neuropsychiatric disorders such as depression, schizophrenia, and multiple sclerosis. The memory effects of each condition differ, but are all related to alterations in brain physiology and general memory deterioration. Exercise, or physical activity, has been demonstrated to attenuate memory interference in some cases, but the mechanisms are still being determined. Further research is needed on memory interference, in regard to exercise and neuropsychiatric disorders.
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Affiliation(s)
- Lindsay Crawford
- Department of Health, Exercise Science, and Recreation Management, Exercise and Memory Laboratory, The University of Mississippi, MS, Oxford, USA
| | - Paul D Loprinzi
- Department of Health, Exercise Science, and Recreation Management, Exercise and Memory Laboratory, The University of Mississippi, MS, Oxford, USA.
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2
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Abstract
SummaryA minimal brain damage examination was carried out in 73 schizophrenic patients divided into three groups according to their season of birth. Results showed no statistically significant difference among groups in the prevalence of neurological soft signs.
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Modestin J, Würmle O, Ammann R. Failure to identify a male winter-born schizophrenia subgroup clinically. Eur Psychiatry 2020; 11:34-9. [DOI: 10.1016/0924-9338(96)80456-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/1994] [Accepted: 08/29/1995] [Indexed: 11/16/2022] Open
Abstract
SummaryThe distribution of 282 Research Diagnostic Criteria (RDC) and of 224 DSM-III-R schizophrenic patients, respectively, by month of their birth was studied. The winter-spring birth rate excess was confirmed with a maximum from January to March. Winterborn and summer-born schizophrenics were compared. No convincing differences were found with regard to a larger set of demographic, psychosocial and clinical variables in univariate comparisons, nor did we succeed in separating and identifying a special winter-born schizophrenia subgroup using the method of cluster analysis. Negative results were obtained in spite of the fact that many of the included variables reflected the course of the illness and the degree of chronicity. Either the set of the variables we used has not been ‘correct’ enough or the separation of a winter-born subgroup is not clinically feasible.
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LE L, R K, B M, Mj G. Risk of schizophrenia in relatives of individuals affected by schizophrenia: A meta-analysis. Psychiatry Res 2020; 286:112852. [PMID: 32065982 DOI: 10.1016/j.psychres.2020.112852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 12/31/2022]
Abstract
A meta-analysis was conducted to estimate schizophrenia incidence in first-degree relatives (FDRs) of probands diagnosed with schizophrenia. The aim was to inform future schizophrenia research and improve accuracy of risk communication to patients. Schizophrenia risk in FDRs with 1 or 2 probands with schizophrenia was investigated by conducting a systematic review of cohort and case-control studies with the following criteria: published between 1977 and 2018; reported odds ratios (OR), relative risk (RR) or sufficient raw data to calculate OR or RR; used appropriate diagnostic criteria; and reported systematic proband recruitment and ascertainment of relatives. Studies were obtained via EMBASE and MEDLINE electronic database searches. From an initial 5755 articles, 19 met the inclusion criteria. Mean effect sizes across studies were estimated using random effects methods. Estimates for schizophrenia risk were OR = 7.69 (95% CI 5.11-11.56) for FDRs of one proband with schizophrenia compared to healthy control probands, increasing to OR = 11.11 (95% CI = 1.45-85.02) for FDRs with two probands with schizophrenia. These findings support the existing literature suggesting significant genetic liability for schizophrenia. The results can be used to educate individuals with a family history of schizophrenia about their risk.
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Affiliation(s)
- Lo LE
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia
| | - Kaur R
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia
| | - Meiser B
- Psychosocial Research Group, Prince of Wales Clinical School, Sydney, NSW, Australia.
| | - Green Mj
- School of Psychiatry, University of New South Wales, NSW 2052, Australia; Neuroscience Research Australia, Sydney, NSW 2031, Australia
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Escott-Price V, Smith DJ, Kendall K, Ward J, Kirov G, Owen MJ, Walters J, O’Donovan MC. Polygenic risk for schizophrenia and season of birth within the UK Biobank cohort. Psychol Med 2019; 49:2499-2504. [PMID: 29501066 PMCID: PMC7610956 DOI: 10.1017/s0033291718000454] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND There is strong evidence that people born in winter and in spring have a small increased risk of schizophrenia. As this 'season of birth' effect underpins some of the most influential hypotheses concerning potentially modifiable risk exposures, it is important to exclude other possible explanations for the phenomenon. METHODS Here we sought to determine whether the season of birth effect reflects gene-environment confounding rather than a pathogenic process indexing environmental exposure. We directly measured, in 136 538 participants from the UK Biobank (UKBB), the burdens of common schizophrenia risk alleles and of copy number variants known to increase the risk for the disorder, and tested whether these were correlated with a season of birth. RESULTS Neither genetic measure was associated with season or month of birth within the UKBB sample. CONCLUSIONS As our study was highly powered to detect small effects, we conclude that the season of birth effect in schizophrenia reflects a true pathogenic effect of environmental exposure.
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Affiliation(s)
| | - Daniel J. Smith
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
| | - Kimberley Kendall
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Joey Ward
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
| | - George Kirov
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Michael J. Owen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - James Walters
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Michael C. O’Donovan
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
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6
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McTigue O, O’Callaghan E. Season of Birth as a Risk Factor. INTERNATIONAL JOURNAL OF MENTAL HEALTH 2015. [DOI: 10.1080/00207411.2000.11449497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Svensson AC, Lichtenstein P, Sandin S, Öberg S, Sullivan PF, Hultman CM. Familial aggregation of schizophrenia: the moderating effect of age at onset, parental immigration, paternal age and season of birth. Scand J Public Health 2011; 40:43-50. [PMID: 21930618 DOI: 10.1177/1403494811420485] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIMS An abundance of evidence has firmly established the familial aggregation of schizophrenia. The aim of this study was to examine how age at onset, parental characteristics and season of birth modify the familiality in schizophrenia. METHODS A population-based cohort was created by linking the Swedish Multi-Generation and Hospital Discharge Registers. Among 5,075,998 full siblings born between 1932 through to 1990, 16,346 cases of schizophrenia were identified. Familial aggregation was measured by the sibling recurrence-risk ratio, defined as the risk of schizophrenia among full siblings of schizophrenia patients compared with the risk among siblings of unaffected people. RESULTS We found a statistically significantly lower recurrence-risk ratio in siblings of later onset cases (7.2; 95% confidence interval (95% CI) 6.7-7.9) than of early onset cases (10.8; 95% CI 9.4-12.2). A lower recurrence-risk ratio was observed among offspring to fathers above 40 years (6.3; 95% CI 5.3-7.3) as compared with offspring of younger fathers (8.6; 95% CI 8.0-9.3). Further, among offspring to parents born outside Sweden the recurrence-risk ratio was statistically significantly lower (maternal immigrants 4.8; 95% CI 4.0-5.7, paternal immigrants 5.7; 95% CI 4.6-6.9) than among offspring to parents born in Sweden. CONCLUSIONS The familial aggregation of schizophrenia was reduced by higher age at onset, advancing paternal age and immigrant status of parents.
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Affiliation(s)
- Anna C Svensson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
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van Os J, Rutten BPF, Poulton R. Gene-environment interactions in schizophrenia: review of epidemiological findings and future directions. Schizophr Bull 2008; 34:1066-82. [PMID: 18791076 PMCID: PMC2632485 DOI: 10.1093/schbul/sbn117] [Citation(s) in RCA: 408] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Concern is building about high rates of schizophrenia in large cities, and among immigrants, cannabis users, and traumatized individuals, some of which likely reflects the causal influence of environmental exposures. This, in combination with very slow progress in the area of molecular genetics, has generated interest in more complicated models of schizophrenia etiology that explicitly posit gene-environment interactions (EU-GEI. European Network of Schizophrenia Networks for the Study of Gene Environment Interactions. Schizophrenia aetiology: do gene-environment interactions hold the key? [published online ahead of print April 25, 2008] Schizophr Res; S0920-9964(08) 00170-9). Although findings of epidemiological gene-environment interaction (G x E) studies are suggestive of widespread gene-environment interactions in the etiology of schizophrenia, numerous challenges remain. For example, attempts to identify gene-environment interactions cannot be equated with molecular genetic studies with a few putative environmental variables "thrown in": G x E is a multidisciplinary exercise involving epidemiology, psychology, psychiatry, neuroscience, neuroimaging, pharmacology, biostatistics, and genetics. Epidemiological G x E studies using indirect measures of genetic risk in genetically sensitive designs have the advantage that they are able to model the net, albeit nonspecific, genetic load. In studies using direct molecular measures of genetic variation, a hypothesis-driven approach postulating synergistic effects between genes and environment impacting on a final common pathway, such as "sensitization" of mesolimbic dopamine neurotransmission, while simplistic, may provide initial focus and protection against the numerous false-positive and false-negative results that these investigations engender. Experimental ecogenetic approaches with randomized assignment may help to overcome some of the limitations of observational studies and allow for the additional elucidation of underlying mechanisms using a combination of functional enviromics and functional genomics.
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Affiliation(s)
- Jim van Os
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University Medical Centre, EURON, SEARCH, Maastricht, The Netherlands.
| | - Bart PF Rutten
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University Medical Centre, EURON, SEARCH, PO Box 616 (location DOT 10), Maastricht, 6200 MD, The Netherlands
| | - Richie Poulton
- Dunedin Multidisciplinary Health and Development Research Unit, Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, PO Box 913, Dunedin, New Zealand
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9
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Suvisaari JM, Haukka JK, Lönnqvist JK. No association between season of birth of patients with schizophrenia and risk of schizophrenia among their siblings. Schizophr Res 2004; 66:1-6. [PMID: 14693347 DOI: 10.1016/s0920-9964(02)00506-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous studies on the relationship between the season of birth of patients with schizophrenia and the risk of schizophrenia among their siblings have yielded contradictory results. We investigated whether proband's month of birth affects siblings' risk of developing schizophrenia. We used the Finnish Hospital Discharge Register to identify all patients born in Finland from 1950 to 1976 who had been hospitalized because of schizophrenia at least once between 1969 and 1995. Their siblings were identified from the National Population Register, and data on siblings were linked to the Hospital Discharge Register to obtain information on any hospitalizations. We used logistic regression to investigate a sibling's probability of developing schizophrenia, defining the proband initially as the first sibling in calendar time to develop schizophrenia, then as the affected sibling with lowest onset age. Within-family dependence was taken into account by using robust standard error estimates. Neither models found any association between proband's month of birth and siblings' odds of developing schizophrenia. Our results support those previous studies that found no association between proband's month of birth and family history of schizophrenia, and suggest that the winter-spring excess of births among patients with schizophrenia is not caused by any genetic or environmental risk factor that operates independently of other risk factors.
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Affiliation(s)
- Jaana M Suvisaari
- Department of Mental Health and Alcohol Research, National Public Health Institute, Mannerheimintie 166, FIN-00300 Helsinki, Finland.
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10
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McDonald C, O'Callaghan E, Keogh F, Sham PC, Kinsella A, Morris M, Walsh D. Number of older siblings of individuals diagnosed with schizophrenia. Schizophr Res 2001; 47:275-80. [PMID: 11278145 DOI: 10.1016/s0920-9964(00)00134-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One of the most consistent epidemiological findings in schizophrenia research is the small excess of late winter/early spring births. There is also evidence that schizophrenia is associated with urban birth and with later birth order. One interpretation of these three findings is that respiratory viral infections brought into the household by children in crowded areas could disrupt foetal brain development and predispose to schizophrenia in later life. To further explore this hypothesis, case register data were used to assess if schizophrenics with a greater number of older siblings are more likely to be born in urban areas and during late winter/early spring months. Data from the Dublin and Three County Case Register were compiled relating to 2969 patients with schizophrenia and 5904 patients with neurosis. We used logistic regression analysis to determine if the number of older siblings differentiated schizophrenia from neurosis after controlling for the effects of gender, urban/rural birth, season of birth and sibship size, and to examine whether any interactions existed. The number of older siblings did not predict a diagnosis of schizophrenia over neurosis. There was no interaction between number of older siblings and urban birth, between number of older siblings and spring birth, or between number of older siblings, season of birth and urban birth. These data do not support the hypothesis that schizophrenia, by comparison with neurosis, is associated with an increased number of older siblings or that there is an interaction between number of older siblings, urban birth or season of birth.
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Affiliation(s)
- C McDonald
- Cluain Mhuire Family Centre, Newtownpark Avenue, Blackrock, County Dublin, Ireland
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11
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Kinney DK, Jacobsen B, Jansson L, Faber B, Tramer SJ, Suozzo M. Winter birth and biological family history in adopted schizophrenics. Schizophr Res 2000; 44:95-103. [PMID: 10913740 DOI: 10.1016/s0920-9964(99)00162-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To investigate relationships between birth season and biological family history in schizophrenia, this study used a sample of schizophrenics that had the advantages of (a) particularly thorough diagnostic assessments of schizophrenics' relatives, including information from direct interviews as well as chart reviews, and (b) schizophrenic probands who were adopted at early age, mitigating the usual confounding of genetic and postnatal environmental influences of the family. Adopted schizophrenics with no biological family history of schizophrenia-spectrum disorders were significantly more likely to be born in winter months than were either (a) their own biological relatives, including their sibs and half-sibs, (b) schizophrenics with a positive family history for schizophrenia-spectrum disorders, or (c) people in the general population. Family-history-positive schizophrenics and their schizophrenic relatives were, in turn, significantly less likely than their own non-schizophrenic biological relatives to be born in the winter; schizophrenics in these families tended to be born in the milder-weather seasons, particularly the spring and fall. Results suggest that environmental factors associated with winter birth may be etiologically important in schizophrenia, particularly for cases in which familial liability factors are weak. By contrast, a familial, probably genetic, liability factor may be especially important in schizophrenics born in mild weather.
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Affiliation(s)
- D K Kinney
- Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
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12
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Torrey EF, Miller J, Rawlings R, Yolken RH. Seasonality of births in schizophrenia and bipolar disorder: a review of the literature. Schizophr Res 1997; 28:1-38. [PMID: 9428062 DOI: 10.1016/s0920-9964(97)00092-3] [Citation(s) in RCA: 395] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
More than 250 studies, covering 29 Northern and five Southern Hemisphere countries, have been published on the birth seasonality of individuals who develop schizophrenia and/or bipolar disorder. Despite methodological problems, the studies are remarkably consistent in showing a 5-8% winter-spring excess of births for both schizophrenia and mania/bipolar disorder. This seasonal birth excess is also found in schizoaffective disorder (December-March), major depression (March-May), and autism (March) but not in other psychiatric conditions with the possible exceptions of eating disorders and antisocial personality disorder. The seasonal birth pattern also may shift over time. Attempts to correlate the seasonal birth excess with specific features of schizophrenia suggest that winter-spring births are probably related to urban births and to a negative family history. Possible correlations include lesser severity of illness and neurophysiological measures. There appears to be no correlation with gender, social class, race, measurable pregnancy and birth complications, clinical subtypes, or neurological, neuropsychological, or neuroimaging measures. Virtually no correlation studies have been done for bipolar disorder. Regarding the cause of the birth seasonality, statistical artifact and parental procreational habits are unlikely explanations. Seasonal effects of genes, subtle pregnancy and birth complications, light and internal chemistry, toxins, nutrition, temperature/weather, and infectious agents or a combination of these are all viable possibilities.
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Affiliation(s)
- E F Torrey
- Stanley Foundation Research Programs, NIMH Neuroscience Center, St. Elizabeths Hospital, Washington, DC 20032, USA
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Dassa D, Sham PC, van Os J, Abel K, Jones P, Murray RM. Relationship of birth season to clinical features, family history, and obstetric complication in schizophrenia. Psychiatry Res 1996; 64:11-7. [PMID: 8888360 DOI: 10.1016/0165-1781(96)02868-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
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 192 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.
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Affiliation(s)
- D Dassa
- Département de Psychiatrie, C.H.U. Timone, Marseille, France
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14
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Chen WJ, Yeh LL, Chang CJ, Lin LC, Rin H, Hwu HG. Month of birth and schizophrenia in Taiwan: effect of gender, family history and age at onset. Schizophr Res 1996; 20:133-43. [PMID: 8794501 DOI: 10.1016/0920-9964(95)00072-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Schizophrenic patients have been shown to have a moderate excess of winter births in the areas where seasonal variations in weather are large. In this report, we examined the seasonality of schizophrenic births in Taiwan, which has a subtropical climate. Using nationwide hospitalization data (2429 male and 1320 female schizophrenic patients), we applied the life table method to compare the risk of schizophrenia among 12 cohorts of month-of-birth for males and females, respectively. Differences among the risks of the 12 cohorts were tested using the logrank test. The samples were further stratified by family history and age at onset. There was a significant association between the risk of being admitted as a schizophrenic and month of birth for both males and females. The cohorts born in November and January had the highest risks. After stratification, the association was significant only for non-familial, male, and early onset schizophrenic patients. The results indicate that seasonally varying factors might increase the risk of schizophrenia, especially in those without a family history of the disease. Men are more vulnerable to such factors than women, and the schizophrenics resulting from such insults tend to be early onset.
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Affiliation(s)
- W J Chen
- Institute of Epidemiology, College of Public Health, National Taiwan University
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15
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d'Amato T, Guillaud-Bataille JM, Rochet T, Jay M, Mercier C, Terra JL, Daléry J. No season-of-birth effect in schizophrenic patients from a tropical island in the Southern Hemisphere. Psychiatry Res 1996; 60:205-10. [PMID: 8723312 DOI: 10.1016/0165-1781(96)02794-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The distribution of birth rates was examined in 668 schizophrenic patients born in Réunion, a tropical French island in the Southern Hemisphere, and compared with that in the general local population. We failed to observe a significant season-of-birth effect, either in the total sample of schizophrenic patients or in subgroups categorized by gender, age, or family history of schizophrenia. Seasonal factors do not appear to affect the yearly distribution of births among schizophrenic patients on Réunion Island. It is nevertheless possible that environmental factors which are seasonal in countries with more contrasting climates have a continuous effect, throughout the whole year, in subtropical areas. Conversely, these findings provide some evidence against the hypothesis that there is an age-incidence artifact in seasonal studies from countries in the Northern Hemisphere.
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Affiliation(s)
- T d'Amato
- Hôpital du Vinatier, Lyon-Bron, France
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16
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Hettema JM, Walsh D, Kendler KS. Testing the effect of season of birth on familial risk for schizophrenia and related disorders. Br J Psychiatry 1996; 168:205-9. [PMID: 8837911 DOI: 10.1192/bjp.168.2.205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND An excess of late winter and early spring births in schizophrenia has been repeatedly demonstrated. Previous evidence has suggested that the risk for schizophrenia may differ in relatives of schizophrenic probands born in this high risk period v. at other times of the year. METHOD In an epidemiologically based family study conducted in the west of Ireland, we examined the relationship between season of birth in schizophrenia and schizophrenia spectrum probands and the risk for schizophrenia and related disorders in first-degree relatives. Risk was assessed using the Cox proportional hazard method. We examined four birth seasons previously shown to significantly predict risk for schizophrenia. RESULTS Neither the risk for schizophrenia nor that for schizophrenia spectrum disorders in relatives was significantly associated with season of birth in probands. CONCLUSIONS Season of birth does not, in this sample, identify schizophrenic probands with particularly high or low familial vulnerability to illness.
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Affiliation(s)
- J M Hettema
- Department of Psychiatry, Medical College of Virginia/VCU, Richmond 23298-0710, USA
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17
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Abstract
The distinction between winter-born (WBS) and non-winter born (NWBS) schizophrenic cases has been proposed as a strategy to identify distinct etiologic subtypes within schizophrenia, the WBS subgroup being a predominantly environmental subtype. The goal of this paper is to empirically test the validity of this strategy by comparing WBS and NWBS groups on a broad array of clinical and biological variables. DSM-III-R schizophrenic, schizoaffective and schizophreniform subjects were comprehensively assessed using (i) the Comprehensive Assessment of Symptoms and History; (ii) a comprehensive neurological exam; (iii) a neuropsychological battery, including IQ and the Continuous Performance Test and (iv) an MRI scanning. The patients were divided into WBS and NWBS, using five alternative sets of definitions of winter birth. These comparisons yielded no differences between the groups on any of the 23 variables. The results suggest that the distinction between winter-born and non-winter-born cases has very limited power to identify distinct schizophrenic subtypes, and that better delineation of the correlates of environmental risk factors in schizophrenia will require a better identification of these factors.
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Affiliation(s)
- M A Roy
- Department of Psychiatry, University of Iowa Hospitals and Clinics, Iowa City, USA
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18
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O'Callaghan E, Cotter D, Colgan K, Larkin C, Walsh D, Waddington JL. Confinement of winter birth excess in schizophrenia to the urban-born and its gender specificity. Br J Psychiatry 1995; 166:51-4. [PMID: 7894876 DOI: 10.1192/bjp.166.1.51] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND The season of birth phenomenon in schizophrenia was reexamined in relation to place of birth, in order to test the hypothesis that a seasonal factor might operate preferentially among those who were urban-born. METHOD The seasonal distribution of births was examined among 3253 patients in two case registers having an ICD-9 diagnosis of schizophrenia and compared with the distribution of births among the normal population born in those catchment areas over the same period; those subjects born in population centres greater than 50,000 were defined as urban-born. RESULTS Patients who were urban-born showed an excess of winter births relative to controls that was absent among their rural-born counterparts. On comparing patient groups, those who were urban-born were more likely to be born in the winter, while those who were rural-born were more likely to be born in the spring; this urban-rural distinction was confined essentially to female patients. CONCLUSIONS These findings might be accommodated most readily in terms of a spatially as well as seasonally varying environmental factor that is associated with urbanicity and to which female offspring are more vulnerable.
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Affiliation(s)
- E O'Callaghan
- St John of God Psychiatric Services, Cluain Mhuire Family Centre, Dublin, Ireland
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Abstract
Recent neuroimaging and neuropathological studies suggest a developmental origin for schizophrenia. Some cases may, therefore, be caused by a genetic defect in the specification of brain development. Early environmental hazards such as obstetric complications, and maternal exposure during pregnancy to influenza epidemics, have also been found to increase the risk of later schizophrenia. The relationship between the prevalence of influenza and birth date has been found more consistently for female than male schizophrenics. Female schizophrenia is also associated with a higher risk of schizophrenia in first degree relatives. This raises the question of whether part of the genetic predisposition to schizophrenia may comprise an abnormal reaction to maternal influenza.
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Affiliation(s)
- R M Murray
- Department of Psychological Medicine, Institute of Psychiatry, London, U.K
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Sacchetti E, Calzeroni A, Vita A, Terzi A, Pollastro F, Cazzullo CL. The brain damage hypothesis of the seasonality of births in schizophrenia and major affective disorders: evidence from computerised tomography. Br J Psychiatry 1992; 160:390-7. [PMID: 1562867 DOI: 10.1192/bjp.160.3.390] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although the excess of schizophrenic births in the winter and early spring has been replicated and some non-conclusive work supports the same seasonal birth trend in patients with major affective disorders, the aetiopathogenetic foundations of this phenomenon remain uncertain. The primary role of perinatal seasonal factors that predispose to the development of schizophrenia via induction of brain damage has been invoked, as has a tendency for patients to conceive during the spring and early summer. In order to test these two hypotheses, cerebral ventricular size and cortical atrophy in 206 schizophrenics and 107 patients with major affective disorders were assessed by CT and analysed in relation to month of birth. Compared with schizophrenics born during the remainder of the year, those born between December and April, particularly in cases lacking a family history of schizophrenia, showed increased chances for ventricular enlargement, but not for cortical atrophy. No association between season of birth and central or cortical atrophy was found for patients with major affective disorders. This suggests that the brain-damaging effect played by perinatal seasonal factors has both a disease and an anatomical specificity.
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Affiliation(s)
- E Sacchetti
- University Service of Psychiatry, Ospedale San Paolo, Milan, Italy
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21
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Pulver AE, Liang KY, Wolyniec PS, McGrath J, Melton BA, Adler L, Childs B. Season of birth of siblings of schizophrenic patients. Br J Psychiatry 1992; 160:71-5. [PMID: 1544015 DOI: 10.1192/bjp.160.1.71] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The hypothesis that mothers of winter-spring-born schizophrenics have an unusual pattern of conception which results in an excess of winter-spring births was tested by studying the distribution of birth-dates of 401 siblings of 120 winter-spring-born schizophrenics and 157 siblings of 59 winter-spring-born controls. All analyses were gender-specific. The results suggest there is no association between the probability of a winter-spring date of birth and being a sibling of a winter-spring-born schizophrenic or control.
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Affiliation(s)
- A E Pulver
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21203
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22
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O'Callaghan E, Gibson T, Colohan HA, Walshe D, Buckley P, Larkin C, Waddington JL. Season of birth in schizophrenia. Evidence for confinement of an excess of winter births to patients without a family history of mental disorder. Br J Psychiatry 1991; 158:764-9. [PMID: 1873629 DOI: 10.1192/bjp.158.6.764] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Although it is well recognised that schizophrenic patients are more often born in winter, the significance of this finding remains obscure. Data relating to season of birth and family history were analysed for 561 patients with an ICD-9 diagnosis of schizophrenia. Patients with no family history of any psychiatric disorder group were significantly more likely to be born in winter than patients with a first-degree relative affected by schizophrenia. In comparison with normal population controls, only those without a family history exhibited a significant excess of winter births, suggesting an environmental factor of greater aetiological significance in these patients.
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Ohlund LS, Ohman A, Alm T, Ost LG, Lindström LH. Season of birth and electrodermal unresponsiveness in male schizophrenics. Biol Psychiatry 1990; 27:328-40. [PMID: 2302440 DOI: 10.1016/0006-3223(90)90007-o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The present study was designed to examine differences in the electrodermal activity of schizophrenics born in the season of excessive risk (January-April), and those born in the season of nonexcessive risk (May-December). Thirty-two male schizophrenics were presented with a series of orienting tones (1000 Hz, 80dB, 2 sec duration) while electrodermal activity was monitored. They were subdivided according to season of birth and compared in three electrodermal variables, and also in some background and clinical parameters. We found that schizophrenics born in the season of excessive risk were characterized by significantly lower electrodermal activity and more negative symptoms than those born in the season of nonexcessive risk.
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Affiliation(s)
- L S Ohlund
- Department of Clinical Psychology, University of Uppsala, Sweden
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Fañanas L, Marti-Tusquets JL, Bertranpetit J. Seasonality of birth in schizophrenia. An insufficient stratification of control population? Soc Psychiatry Psychiatr Epidemiol 1989; 24:266-70. [PMID: 2510320 DOI: 10.1007/bf01788969] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The seasonality of birth in 142 schizophrenics from Barcelona (Spain) has been studied, showing a pattern similar to that described by other authors, with a maximum in winter. If sample is compared with the local general population there are significant differences, but these disappear when the comparison is made with a control population properly stratified by age, sex, place of birth, place of residence and social status. The same results are obtained using statistical methods suggested by other authors. The seasonality pattern usually obtained in schizophrenia could be due to a selective stratification of the ill population based on variables that might or might not be related to illness.
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