Personality features of patients with primary affective disorder.

Personality variables were assessed in outpatients with primary affective disorder by use of the Maudsley Personality Inventory (MPI) and the Marke Nyman Temperament Scale (MNTS). Significant differences between diagnostic groups were initially noted for the extraversion and neuroticism scales of the MPI. However, when mood was more rigorously controlled for, these differences largely disappeared, while interdiagnostic differences for the solidity scale of the MNTS emerged. The findings suggest that these measured aspects of personality may be quite state (mood) dependent even when patients are given test instructions previously reported to minimize mood effects. This was born out in a follow-up study for the N scale, but not the E scale, of the MPI. These data indicate that assessment of neuroticism in affectively ill patients will be contaminated by the presence of even mild depressive symptoms, a finding that has important implications for studies of personality in affective disorder.