BackgroundThe aim of the present study is to evaluate the role of individual affective temperaments as clinical predictors of bipolarity in the clinical setting.MethodsThe affective temperaments of 1723 consecutive adult outpatients presenting for various symptoms to a university-based mental health clinical setting were assessed. Patients were administered the Hypomania Checklist-32 and the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego – Auto-questionnaire (TEMPS-A) and were diagnosed by psychiatrists according to the DSM-5 criteria. TEMPS-A scores were studied as both continuous and normalized categoricalz-scores from a previously established nationwide study on the general population of Lebanon. Simple and multiple binary logistic regressions were done on patients who have any of the DSM-5 defined bipolar types, as a combined group or separately, versus patients without any bipolar diagnosis.ResultsAt the multivariable level and taking into account all temperaments, the irritable temperament is a consistent predictor of bipolar I and bipolar II disorders. Cyclothymic temperament also played a strong role in bipolarity but more decisively so in bipolar II and substance-induced bipolarity. The hyperthymic temperament had no role in bipolar I or bipolar II disorder.