Subjective well-being: genetic and environmental contributions to stability and change

Background. Previous cross-sectional Studies have found Substantial genetic Influences on individual variation in Subjective well-being (SWB). and evidence for sex-specific genetic effects has been reported. However, the genetic and environmental influences on stability and change in SWB over time are largely unexplored. Method. Questionnaire data on SWB from a population-based sample of Norwegian twins born 1967 to 1979, initially Surveyed in 1992 (T,) and re-surveyed in 1998 (T-1), were analysed using structural equation modelling to explore the relative effects of (genetic and environmental influences on phenotypic stability and change. Results. The phenotypic cross-time correlations for SWB were 0.51 and 0.49 for males and females respectively. The best-fitting longitudinal model specified only additive genetic and individual environmental effects with qualitative and quantitative sex-specific genetic influences. For both mates and females, the additive genetic factors influencing SWB were largely stable. although some time-specific genetic contributions were indicated. Cross-time correlations for genetic effects were 0.85 and 0.78 for males and females respectively. The individual environmental influences were primarily time-specific. Additive genetic effects explained approximately 80% of the phenotypic cross-time correlation. For females. the magnitude of the additive genetic effects decreased significantly from T-1 to T-2, whereas for males. the estimates generally remained unchanged. Conclusions. For both males and females, long-term stability of SWB was mainly attributable to stable additive genetic factors, whereas susceptibility to change was mostly related to individual environmental factors. However. both stable environmental contributions and einer-Lying genetic influences were indicated.