To illustrate the association between personality dimensions and MDD or BD, Table 1 shows the scores for five personality traits measured with the NEO Five-Factor Inventory2 in GAIN-MDD controls, GAIN-MDD cases and STEP-BD cases at entry to the study. Four of the five personality scales were significantly different in MDD patients compared with controls: N scores were higher, whereas A, E and C scores were lower in depressed subjects (all P-values <0.0001 in a t-test). As described in Barnett et al.,6 BD patients at a euthymic phase significantly differed from the population norms for all scales exhibiting higher levels of N and O and lower levels of E, C and A.
