Affective temperaments across the bipolar-unipolar spectrum: Examination of the TEMPS-A in 927 patients and controls

Objective: There is currently a great deal of interest in the use of affective temperaments as possible intermediate phenotypes for bipolar disorder. However, much of the literature in this area is conflicting. Our aims were to test the hypothesis of a gradient in affective temperament scores, as measured by the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-A), from bipolar disorder type I (BP-I), through bipolar disorder type II (BP-II), recurrent major depressive disorder (MDD-R), and a control group (CG) in the largest sample to date of 927 subjects. Methods: Non parametric tests were used to compare TEMPS-A scores between diagnostic groups and multinomial logistic regression was used to test the association between TEMPS-A scores and diagnosis while controlling for current mood state, age and gender. Results: Although the BP-II group scored higher than the BP-I and MDD-R groups on several TEMPS-A subscales, these differences were not significant when confounding variables were controlled for. The dysthymic subscale differentiated between affected and controls and the anxious subscale differentiated the MDD-R group from controls. Limitations: The cross-sectional design did not allow us to evaluate potential longitudinal changes of temperament scores, which were assessed only with a self-report questionnaire. Conclusion: We failed to find evidence of a gradient in affective temperament scores. Both unipolar and bipolar patients reported high dysthymic scores relative to controls, perhaps supporting a unitary view of depression across the bipolar-unipolar spectrum. Taking account of potential confounders will be important in future studies which seek to use affective temperaments as intermediate phenotypes in genetic research. (C) 2009 Elsevier B.V. All rights reserved.