Cyclothymic and hyperthymic temperaments may predict bipolarity in major depressive disorder: A supportive evidence for bipolar II1/2 and IV

BackgroundThe concept of soft bipolar spectrum has not been fully confirmed. The aim of the present study is to investigate the validity of bipolar II1/2 and IV concept.MethodsThe subjects were 46 consecutive outpatients. The individual temperament of each patient was recorded using the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A). The operational definition of bipolar II1/2 was those who had depression with cyclothymic temperament and that of bipolar IV was those who had depression with hyperthymic temperament. Finally, drug responses were investigated.ResultsDSM-IV-TR diagnoses were bipolar I (N = 1), bipolar II (N = 9), major depressive disorder (N = 34) and depressive disorder not otherwise specified (N = 2). Excluding one bipolar I patient, who had both cyclothymic and hyperthymic temperaments, patients with bipolar II1/2 (N = 32) and IV (N = 13) as well as bipolar II (N = 9) were classified into the soft bipolar spectrum, although there was considerable overlap. The categorization of soft bipolar spectrum and unipolar depression significantly predicted depressive, cyclothymic, irritable, and anxious temperaments. Moreover, soft bipolar spectrum patients with lithium treatment were significantly more in remission than those without lithium treatment. In addition, more of those with selective serotonin reuptake inhibitors (SSRIs) had a significant tendency to lower remission than those without SSRIs.LimitationsThis is a cross-sectional study with a relatively small number of subjects.ConclusionsThe present findings suggest that cyclothymic and hyperthymic temperaments may predict bipolarity, and the validity of bipolar II1/2 and IV concept is supported.