In:
Twin Research and Human Genetics, Cambridge University Press (CUP), Vol. 11, No. 3 ( 2008-06-01), p. 257-265
Abstract:
Although life events are often conceptualized as reflecting exogenous risk factors for psychopathology, twin studies have suggested they are heritable. We undertook a mixed twin/adoption study to further explore genetic and environmental contributions to individual differences in the experience of life events. Specifically, a sample of 618 pairs of like-sex adolescent twins, 244 pairs of like-sex adopted adolescent and young adult siblings, and 128 pairs of like-sex biological siblings completed a life events interview. Events were classified as independent (not likely to have been influenced by respondent's behavior), dependent (likely to have been influenced by respondent's behavior), or familial (experienced by a family member), and then summed to form three life event scales. Variance on the scales was assumed to be a function of four factors: additive genetic effects ( a 2 ), shared environmental effects ( c 2 ), twin-specific effects ( t 2 ), and nonshared environmental effects ( e 2 ). Data were analyzed using standard biometrical models. Shared environmental effects were found to be the largest contributor to variance in familial events ( c 2 = .71; 95% confidence interval of .65, .76); additive genetic effects were the largest contributor to dependent events ( a 2 = .45; CI = .31, .58); and nonshared environmental effects were found to be the largest contributor independent events ( e 2 = .57; CI = .51, .64). A significant twin-specific effect was also found for independent life events, indicating that twins are more likely to be exposed to such events than non-twin biological siblings. Findings are discussed in terms of their implication for understanding the nature of psychosocial risk.
Type of Medium:
Online Resource
ISSN:
1832-4274
,
1839-2628
DOI:
10.1375/twin.11.3.257
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2008
detail.hit.zdb_id:
2184274-7
SSG:
12
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