Personality traits were assessed using the Italian version of the Revised NEO Personality Inventory (NEO-PI-R), a 240-item measure of the five dimensions of personality (38). The domain scores are computed by summing up the six facets that compose each factor. Items are answered on a five-point Likert scale, from strongly disagree to strongly agree, and scales are roughly balanced to control for the effect of acquiescence. The NEO-PI-R has a robust factor structure that has been replicated in Italy (44) and in more than 50 cultures (17). Scales have shown longitudinal stability (45), cross-observer agreement, and convergent and discriminant validity in a large body of studies (16). Trained Sardinian psychologists administered the tests. In the Sardinian sample, the NEO-PI-R showed good psychometric properties, with internal consistency reliabilities for the five factors ranging from 0.80 to 0.87, and a factor structure that replicated the American normative structure at the phenotypic and the genetic level (3, 43, 46).
