The Erasmus Rucphen Family (ERF) study is a family-based study including over 3 000 individuals from an isolated population in the South-West region of the Netherlands.38 There were 2 400 individuals for whom both NEO personality and GWA data were available. The mean age of all participants was 49.3 years (SD=14.9) and women constituted 55.8% of the total sample (M=47.4; SD=15, versus in men M=48.2, SD=14).
