Fig. 2.

The final correlated factors model for well-being, DASS-42 total scores and pons volume in twin pairs with corresponding standardized path estimates. We fitted an AE correlated factors model to the 3 variables across both twin pairs. The ellipses indicate the observed variables and the circles indicate unobserved latent factors (either A or E). Single-headed arrows indicate the effect of 1 latent factor on an observed variable, and double-headed arrows indicate correlations or covariances between latent factors. Results suggest significant negative correlations between A and E factors, contributing to variance in well-being and DASS-42 scores. Additive genetics contributing to DASS-42 and well-being scores did not correlate with those contributing to pons volume. There was a significant negative correlation between E factors contributing to well-being scores and pons volume. A = additive genetics; DASS-42 = Depression, Anxiety, Stress Scale; E = unique environment.