Volunteers and design
Recruitment and screening measures were the same as in Study 1, but only individuals with High Ns were selected (⩾16 on neuroticism scale of the EPQ) (Eysenck and Eysenck, 1975). Forty-seven participants were recruited from the general population; five were excluded owing to history of depression (before data collection and randomized group allocation), and six owing to bad quality of data recording (after data collection; four from the citalopram, two from the placebo group). Three more participants (2 from the citalopram, 1 from the placebo group) were excluded as outliers (see definition above), leaving a total sample of 33 (20 males, mean age=23.6±6.1 years), of which 16 received citalopram (10 males, mean N=18.44±2.4) and 17 placebo (10 males, mean N=19.76±1.8). Participants were randomly allocated to receive identical capsules of citalopram 20 mg or placebo, instructed to take them every day after breakfast, and tested on the seventh day of administration, avoiding caffeinated drinks from 2 h before testing.