Genetic influences on psychological well-being: a nationally representative twin study

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.

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.

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.

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.