Personality phenotypes were assessed with the Revised NEO Personality Inventory (NEO-PI-R [53]), a questionnaire consisting of 240 items answered on a five-point Likert scale ranging from strongly disagree to strongly agree. The NEO-PI-R characterizes consistent patterns of thought, feeling, and action for each individual. Five major factors [neuroticism (N), extraversion (E), openness to experience (O), agreeableness (A), and conscientiousness (C)], each of which is a composite of six facets of personality, are measured. The NEO-PI-R provides a comprehensive and detailed assessment of normal adult personality in terms of emotional, interpersonal, experiential, attitudinal, and motivational styles. The inventory has a robust factor structure that has been replicated in Italy [54] and in more than 50 cultures [55]. Scales have shown longitudinal stability, cross-observer agreement, and convergent and discriminant validity in a large body of studies [21]. Two trained Sardinian psychologists administered the tests orally to participants unable to fill out the questionnaire.
