Temperament in the clinical differentiation of depressed bipolar and unipolar major depressive patients

Objective: To examine differences in temperament profiles between patients with recurrent unipolar and bipolar depression. Method: Depressed individuals with recurrent major depressive disorder (MDD) (n=94) and those with bipolar (n=59) disorders (about equally divided between types I and II) were recruited by newspaper advertisement, radio and television announcements, flyers and newsletters, and word of mouth. All patients were interviewed using the Structured Clinical Interview for DSM III-R (SCID) and had the severity of their depressive episode assessed by means of the 17-item Hamilton Rating Scale for Depression. All patients filled out the TEMPS-A, a validated instrument. Results: Temperament differences between bipolar and MDD patients were examined using MANCOVA. Overall significant effect of the fixed factor (bipolar vs. unipolar) was noted for the temperament scores [Hotelling's F(5,142)=2.47, p<0.05]. Overall effects were found for age [F(5,142)=2.40, p<0.05], but not for gender and severity of depression [F(5,142)=1.65, p=0.15 and F(5,142)=0.66, p=0.66, respectively]. Dependent variables included the five subscales of the TEMPS-A, but only the cyclothymic temperament scores showed significant between-group differences. Limitation: Small bipolar subsample cell sizes did not permit to test the specificity of the findings for bipolar II vs. bipolar I patients. Conclusion: The finding that the clyclothymic subscale is significantly elevated in the bipolar vs. the unipolar depressive group supports the theoretical assumptions upon which the scale is based, and suggests that it might become a useful tool for clinical and research purposes.