The article reviews the conceptual history of "hyperthymia". Since K. W. Stark had used this term in the early 19(th) century, it has developed in two different directions: (1) to delineate a psychopathological syndrome and (2) to define a type of personality disorder (psychopathy). As Kurt Schneider's personality disorder (psychopathy) concept was easily understood and highly practicable, it became influential during the 20(th) century. Earlier before, psychiatrists such as E. Mendel, C. Wernicke and C. G. lung had described entities such as "chronic mania", "hypomania" or "sanguinic degeneration", which were rather similar to each other. We analyze the historical development of such concepts. Emil Kraepelin was highly influential, as he introduced "constitutional excitation" into a broad concept of manic-depressive illness and saw it as a very mild form. After Kraepelin such spectrum concept was first forgotten. Only in recent years these historical considerations were confirmed by empirical observations, although a separate hyperthymic disorder is neither part of DSM-IV nor ICD-10. The concept of a hyperthymic temperament or a hyperthymic personality is a trait-marker and should be differentiated from hypomania as a state-marker. Nowadays, the importance of hyperthymia is not so much one of a disorder requiring treatment; rather the concept has interesting genetic, diagnostic and conceptual consequences.