Whether temperament and character differ between bipolar disorder (BD) and major depressive disorder (MDD) patients and general population subjects, or between BD I and BD II patients, remains unclear.
BD patients (n=191) from the Jorvi Bipolar Study and MDD patients (n=266) from the Vantaa Depression Study (VDS) and the Vantaa Primary Care Depression Study were interviewed at baseline, at 6 and 18 months, and in the VDS at 5 years. A general population comparison group (n=264) was surveyed by mail. BD patients' scores on the Temperament and Character Inventory-Revised were compared at an index interview, when levels of depression and mania were lowest, with scores of MDD patients and controls. BD I (n=99) and BD II (n=92) patients were compared.
Compared with controls, both BD and MDD patients had higher harm avoidance [odds ratio (OR) 1.027, p<0.001 and OR 1.047, p<0.001, respectively] and lower persistence (OR 0.983, p=0.006 and OR 0.968, p<0.001, respectively) scores. Moreover, BD patients had lower self-directedness (OR 0.979, p=0.003), MDD patients lower reward dependence (OR 0.976, p=0.002) and self-transcendence (OR 0.966, p<0.001) scores. BD patients scored lower in harm avoidance (OR 0.980, p=0.002) and higher in novelty seeking (OR 1.027, p<0.001) and self-transcendence (OR 1.028, p<0.001) than MDD patients. No differences existed between BD I and II patients.
The patterns of temperament and character dimensions differed less between BD and MDD patients, than patients from their controls. The most pronounced difference was higher novelty seeking in BD than MDD patients. The dimensions investigated are unlikely to differ between BD I and BD II patients.