Genetic Influences on Psychological Well-Being: A Nationally Representative Twin Study

Objective:Psychological well-being,or eudaimonia,features strongly in theories of human development and thriving.However, the factors of eudaimonia are debated, and their genetic architecture has not been studied in detail. Method: A classical twin design was used to decompose behavioral variance into genetic and environmental components implemented in a multigroup,multivariate structural equation modeling framework.Subjects were 837 pairs of adult U.S.twins from the nationally representative MIDUS II sample.Psychological well-being was measured using the 42-item Ryff Psychological Well-Being Scale,which assesses autonomy,environmental mastery,personal growth,positive relations with others,purpose in life, and self-acceptance. Results: Substantial genetic influences were observed on all components of well-being.Attempts to model these six factors as reflecting a single common psychological mechanism gave a poor fit to the data.The best-fitting model supported the existence of five distinct genetic effects. Effects of shared environment were weak and nonsignificant. Unique environmental effects for all measures were mostly trait specific. Conclusions: These results indicate that psychological well-being is underpinned by a general genetic factor influencing self-control, and four underlying biological mechanisms enabling the psychological capabilities of purpose, agency, growth, and positive social relations.