Cyclothymic temperament and major depressive disorder: a study on Italian patients

Classical authors had hypothesized that affective temperaments represent the subclinical manifestations of mood disorders: in particular, cyclothymic and hyperthymic temperaments have been considered as a subthreshold variant of bipolar disorder. The aim of our study is to test the presence of affective temperaments in a group of Italian patients with major depressive disorder (MDD), and to test the association between cyclothymic temperament and well-established validators of bipolar disorder diagnosis such as age at onset and family history of bipolar disorder.

Patients with diagnosis of major depressive disorder (DSM-IV-TR) were included in the study. Affective temperaments have been evaluated through the Italian semistructured interview version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-I). In order to improve the accuracy of family history and age at onset reports, close family members of the patients were also interviewed.

104 of patients included in the study have completed the temperament interview. 25.5% were diagnosed with a dominant affective temperament. Cyclothymic affective temperament was the most represented in the sample of MDD patients (12.3%); depressive, hyperthymic and irritable temperaments have been detected respectively in 7.5%, 2.8% and 2.8% of patients. Patients with CT showed a significantly lower age at onset of MDD than "pure" MDD patients (31.9 vs. 40.9 years; p=0.049) and higher rates of family history of bipolar disorder in first degree relatives (15.4% vs. 0%; p=0.001).

The major limitation of this study was the lack of a group of bipolar depressives, which would have been useful in order to confirm the similarities of age at onset and bipolar family history with cyclothymic MDD.

Our data confirm previous reports in a sample of accurately screened patients with unipolar major depression: we found that patients with a cyclothymic temperament had an earlier age at onset and a higher family history for bipolar disorder than patients without any dominant affective temperament. Further research is needed to ascertain whether patients with "unipolar" cyclothymic MDD respond to mood stabilizers.