extraversion (E) and novelty seeking (NS) were assessed by a self-report questionnaire associated with the MM2 study (n~2740). SE was measured by the Rosenberg scale (Rosenberg, 1965), N and E by the Eysenck Personality Questionnaire short-form (Eysenck et al. 1985), and NS by a shortened version of the Tridimensional Personality Questionnaire (TPQ) NS scale (Cloninger et al. 1991). N was developed by Eysenck to reflect an individual’s propensity to negative affect or emotionality. Typical items were ‘Are you the type of person (i) whose mood often goes up and down, (ii) whose feeling are easily hurt, and (iii) who is tense or highly strung?’ E was developed by Eysenck to reflect an individual’s sociability and the pleasure obtained from interpersonal interactions. Typical items were ‘Are you the type of person (i) who is rather lively, (ii) who likes mixing with people, and (iii) who can get a party going?’ NS was developed by Cloninger to assess impulsiveness and the desire for high levels of stimulation. Two representative items were: ‘Are you the type of person (i) who often tries new things for the fun or thrills, even if most people think it is a waste of time, and (ii) who,
