Difference in Temperament and Character Inventory scores between depressed patients with bipolar II and unipolar major depressive disorders

Background: Although some core personality variables are known to be characteristic of unipolar or bipolar depression, few studies have compared the personality profile between these two disorders. Methods: Temperament and Character Inventory (TCI) was employed to assess the personality of 36 depressed patients with bipolar II disorder (BPII), 90 patients with unipolar major depressive disorder (UP), and 306 healthy controls. The TCI was administered during the depressive episode in BPII and UP patients so that the results can be applied in a clinical setting. Results: Significantly higher scores in harm avoidance (p < 0.0001) and lower scores in self-directedness (p < 0.0001) and cooperativeness (p < 0.05) were observed in both BPII and UP patients compared to controls. Lower novelty seeking in UP patients compared to BPII patients and controls was observed in females (p < 0.0001, p < 0.01, respectively). A significant difference in self-transcendence score was observed between BPII and UP patients in females (p < 0.0005), with higher scores in BPII (p = 0.009) and lower scores in UP (p = 0.046) patients compared to controls. A logistic regression model predicted BPII in depressed females based on novelty seeking and self-transcendence scores with a sensitivity of 89% and a specificity of 73%, but did not accurately predict BPII in males. Limitations: Patients in our study were limited to those receiving outpatient treatments, and bipolar patients were limited to those with BPII. Conclusions: Novelty seeking and self-transcendence scores of TCI might be useful in the differentiation of UP and BPII in female patients.