Causes of individual differences in adolescent optimism: a study in Dutch twins and their siblings.

Rezan Nehir Mavioğlu,Meike Bartels,Dorret I Boomsma

doi:10.1007/s00787-015-0680-x

Abstract

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.

Highlights

Increasing attention and effort has been directed to positive aspects of human behavior and functioning
The objective of this study was to disentangle the causes of individual differences in optimism and pessimism (3 items) and to gain insight into uni- versus bi-dimensionality of the Life Orientation Test-Revised (LOT-R) in an adolescent sample
Additive genetic influences accounted for about one-third of the variance in optimism

Summary

Introduction

Increasing attention and effort has been directed to positive aspects of human behavior and functioning. Optimism research has been a significant part in positive psychology [1, 2]. The trait of optimism is generally defined as expecting positive outcomes in any life event or situation. Optimism has been associated with many mental and physical health conditions, and multiple dimensions of personality. Optimism is related to lower depression levels [4, 5], less academic stress [6], coping [7], and higher health-related quality of life [8, 9]. Optimism predicts positive physical health outcomes [15]. It is associated with lower levels of pain [16], greater serum antioxidants [17], and healthy lipid profiles [18]

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Conclusion