Temperament is an ancient concept of psychological medicine, denoting the optimum mix of emotional traits involving reactivity. Hippocratic medicine ascribed it to four humors and their temperaments. Despite a rocky history during the past 2,500 years, temperament has undergone a renaissance lately. This presentation summarizes the author's collaborative research in 12 countries worldwide, leading to the psychometrically validated Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS). Concurrent validity has been shown with the TPQ and the NEO-FFI. An advantage of the TEMPS is that it is formulated in subaffective terminology and can be easily applied to affective disorders, and by extension, to its biologic underpinnings. It is indeed my thesis that temperament can serve as the bridge between such remote predisposing factors as genes, early experience, and proximate stressful circumstances, with gender playing a moderating influence.

Our research has revealed 5 factors: depressive, anxious, cyclothymic, irritable, and hyperthymic. The cyclothymic and the anxious types appear to be putative endophenotypes for the bipolar spectrum. Clinically, a reversal from temperament (e.g. depressive) to its opposite episode (e.g. mania) seems to fashion mixed states. Furthermore, cyclothymia is a prospective predictor of bipolar II and possibly that of suicide in youth. Unlike personality disorders, which label what is negative about a person, temperaments encompass both liabilities and positive attributes. Among the latter are self-denial and dependability, worrying about one's kin, skepticism and critical-reflective attitudes, romanticism, risk-taking, novelty-seeking, and leadership skills. Interestingly, such qualities often emerge during the recovery period from clinical depression. Along with subaffective traits, these attributes are highly prevalent in clinically well populations. These data suggest that the temperamental foundations of affective disorders in their dilute forms are very much part of human nature. The foregoing formulation fits best into an oligogenic model. These considerations, in turn, have profound implications for psychotherapy, social psychology, the creative process, psychopharmacotherapy, genetics and evolutionary biology.