caa a22 4500 605477752 CHVBK 20210128100402.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00787-015-0680-x doi (NATIONALLICENCE)springer-10.1007/s00787-015-0680-x Causes of individual differences in adolescent optimism: a study in Dutch twins and their siblings [Elektronische Daten] [Rezan Mavioğlu, Dorret Boomsma, Meike Bartels] The aim of this study was to investigate the degree to which genetic and environmental influences affect variation in adolescent optimism. Optimism (3 items and 6 items approach) and pessimism were assessed by the Life Orientation Test-Revised (LOT-R) in 5,187 adolescent twins and 999 of their non-twin siblings from the Netherlands Twin Register (NTR). Males reported significantly higher optimism scores than females, while females score higher on pessimism. Genetic structural equation modeling revealed that about one-third of the variance in optimism and pessimism was due to additive genetic effects, with the remaining variance being explained by non-shared environmental effects. A bivariate correlated factor model revealed two dimensions with a genetic correlation of −.57 (CI −.67, −.47), while the non-shared environmental correlation was estimated to be −.21 (CI −.25, −.16). Neither an effect of shared environment, non-additive genetic influences, nor quantitative sex differences was found for both dimensions. This result indicates that individual differences in adolescent optimism are mainly accounted for by non-shared environmental factors. These environmental factors do not contribute to the similarity of family members, but to differences between them. Familial resemblance in optimism and pessimism assessed in adolescents is fully accounted for by genetic overlap between family members. The Author(s), 2015 Optimism nationallicence Pessimism nationallicence Twin-sibling design nationallicence Adolescence nationallicence Non-shared environment nationallicence Mavioğlu Rezan Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey aut Boomsma Dorret Department of Biological Psychology, Netherlands Twin Register, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT, Amsterdam, The Netherlands aut Bartels Meike Department of Biological Psychology, Netherlands Twin Register, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT, Amsterdam, The Netherlands aut European Child & Adolescent Psychiatry Springer Berlin Heidelberg 24/11(2015-11-01), 1381-1388 1018-8827 24:11<1381 2015 24 787 https://doi.org/10.1007/s00787-015-0680-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00787-015-0680-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mavioğlu Rezan Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey aut NATIONALLICENCE 700 1- Boomsma Dorret Department of Biological Psychology, Netherlands Twin Register, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 700 1- Bartels Meike Department of Biological Psychology, Netherlands Twin Register, VU University Amsterdam, Van der Boechorststraat 1, 1081 BT, Amsterdam, The Netherlands aut NATIONALLICENCE 773 0- European Child & Adolescent Psychiatry Springer Berlin Heidelberg 24/11(2015-11-01), 1381-1388 1018-8827 24:11<1381 2015 24 787