The Norwegian Twin Registry

The structure of well-being: a single underlying factor with genetic and environmental influences

PURPOSE

The structure of well-being has been debated for millennia. Dominant conceptualisations, such as the hedonic and eudaimonic models, emphasise different constituents of the well-being construct. Some previous studies have suggested that the underlying structure of well-being may consist of one or a few general well-being factors. We conducted three studies to advance knowledge on the structure of well-being comprising more than 21,500 individuals, including a genetically informative twin sample.

METHODS

In Study 1, we used hierarchical exploratory factor analysis to identify well-being factors in a population-based sample of Norwegian adults. In Study 2, we used confirmatory factor analysis to examine the model fit of the identified factor model in an independent sample. In Study 3, we used biometric models to examine genetic and environmental influences on general well-being factors.

RESULTS

We identified six well-being factors which all loaded on a single higher-order factor. This higher-order factor may represent a general "happiness factor", i.e. an h-factor, akin to the p-factor in psychopathology research. The identified factor model had excellent fit in an independent sample. All well-being factors showed moderate genetic and substantial non-shared environmental influence, with heritability estimates ranging from 26% to 40%. Heritability was highest for the higher-order general happiness factor.

CONCLUSION

Our findings yield novel insights into the structure of well-being and genetic and environmental influences on general well-being factors, with implications for well-being and mental health research, including genetically informative studies.

Introducing two types of psychological resilience with partly unique genetic and environmental sources

Psychological resilience is indicated when individuals demonstrate good mental health despite exposure to significant stress or adversity. Good mental health may involve low levels of illbeing and/or high levels of wellbeing. There is still very limited knowledge about the potential differences between these outcomes in relation to stressors. We propose a distinction between type 1 and type 2 resilience, examine their underlying genetic and environmental architecture, and identify modifiable resilience factors. The data come from a population-based twin sample (N = 1987, mean age = 63) in the Norwegian Twin Registry. Type 1 and type 2 resilience are operationalised as the residual of anxiety/depression symptoms and life satisfaction, respectively, after lifetime cumulative adversity has been regressed out. We used biometric modelling and cotwin-control linear mixed models to estimate underlying factors and identify predictors while controlling for genetic confounding. The results support the notion of two separate, but partly overlapping types of resilience. We find heritabilities of 0.30 (type 1) and 0.24 (type 2) and a genetic correlation of 0.43. Potentially causal resilience factors include, but are not limited to, meaning in life, physical activity, positive affect and relationship satisfaction. Whereas some factors are associated with both resilience types, other factors are unique to each type.