| 1. |
- Evengård, Birgitta, 1952-, et al.
(författare)
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The epidemiology of chronic fatigue in the Swedish Twin Registry
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1317-1326
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Tidskriftsartikel (refereegranskat)abstract
- CFS-like illness may be more common that previously acknowledged. There is a marked increase in risk by gender. Previous reports that CFS is more prevalent in individuals in certain occupational categories were not confirmed and may have been due to confounding by gender.
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| 2. |
- Kato, K, et al.
(författare)
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A population-based twin study of functional somatic syndromes
- 2009
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Ingår i: Psychological Medicine. - : Cambridge University Press. - 0033-2917 .- 1469-8978. ; 39:3, s. 497-505
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The mechanisms underlying the co-occurrence of the functional somatic syndromes are largely unknown. No empirical study has explicitly examined how genetic and environmental factors influence the co-morbidity of these syndromes. We aimed to examine how the co-morbidity of functional somatic syndromes is influenced by genetic and environmental factors that are in common to the syndromes. METHOD: A total of 31318 twins in the Swedish Twin Registry aged 41-64 years underwent screening interviews via a computer-assisted telephone system from 1998 to 2002. Four functional somatic syndromes (chronic widespread pain, chronic fatigue, irritable bowel syndrome, and recurrent headache) and two psychiatric disorders (major depression and generalized anxiety disorder) were assessed using structured questions based on standard criteria for each illness in a blinded manner. RESULTS: Multivariate twin analyses revealed that a common pathway model with two latent traits that were shared by the six illnesses fit best to the women's data. One of the two latent traits loaded heavily on the psychiatric disorders, whereas the other trait loaded on all four of the functional somatic syndromes, particularly chronic widespread pain, but not on the psychiatric disorders. All illnesses except the psychiatric disorders were also affected by genetic influences that were specific to each. CONCLUSIONS: The co-occurrence of functional somatic syndromes in women can be best explained by affective and sensory components in common to all these syndromes, as well as by unique influences specific to each of them. The findings clearly suggest a complex view of the multifactorial pathogenesis of these illnesses.
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| 3. |
- Lichtenstein, Paul, et al.
(författare)
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Recurrence risks for schizophrenia in a Swedish national cohort
- 2006
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 36:10, s. 1417-1425
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Tidskriftsartikel (refereegranskat)abstract
- Background. Recurrence risk estimates for schizophrenia are fundamental to our understanding of this complex disease. Widely cited estimates are from small/older samples. If these estimates are biased upwards, then the rationale for molecular genetic studies of schizophrenia may not be as solid. Method. We created a population-based, Swedish national cohort by linking two Swedish national registers into a relational database (the Swedish Hospital Discharge Register and the MultiGeneration Register). Affection was defined as the lifetime presence of at least two in-patient hospitalizations with a core schizophrenia diagnosis. Results. Merging the Swedish national registers created a population-based cohort of 7 739 202 individuals of known parentage. The lifetime prevalence of the narrow definition of schizophrenia was 0(.)407% and we estimated that one in every 79 extended Swedish families had been impacted by schizophrenia. The proportion of affected families with multiple affected members was 3(.)81%. Recurrence risk estimates for all relative types were strikingly similar to those reported in smaller and older studies. For example, we estimated lambda(sibs) at 8(.)55 [95% confidence interval (CI) 7(.)86-9(.)57] compared with a literature estimate of 8(.)6. Conclusions. In the largest and most comprehensive sample yet studied, we confirm the accepted estimates of recurrence risks for schizophrenia, and provide more accurate estimates of recurrence risks of schizophrenia in relatives, an estimate of the familial impact of schizophrenia, and the multiplex proportion (essential for gauging the generalizability of findings from multiplex pedigrees). These data may be valuable for planning and interpreting genetic studies of schizophrenia.
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| 4. |
- Sullivan, Patrick F, et al.
(författare)
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Chronic fatigue in a population sample : definitions and heterogeneity
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1337-1348
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Tidskriftsartikel (refereegranskat)abstract
- Our data are consistent with the 'existence' of CFS-like illness although the dominant nosological approach captures population-level variation poorly. We suggest that studying a more parsimonious case definition - impairing chronic fatigue not due to a known cause - would represent a way forward.
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| 5. |
- Sullivan, Patrick F, et al.
(författare)
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Twin analyses of chronic fatigue in a Swedish national sample
- 2005
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Ingår i: Psychological Medicine. - 0033-2917 .- 1469-8978. ; 35:9, s. 1327-1336
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Tidskriftsartikel (refereegranskat)abstract
- Current fatiguing illness appears to be a complex trait resulting from both environmental and genetic sources of variation without pronounced differences by gender.
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