Persistent Depressive Disorder (Dysthymia) and Recurrent Unipolar Major Depressive Disorder

The term depression comes from the Latin “depressio” and indicates a state of dejection perceived by the subject accompanied by extreme suffering and discomfort. “Melancholia” (melas means black and cholé means bile), the term historically used to describe this condition, was first introduced by Hippocrates in the treatise On the Nature of Man [1] based on the humoral theories of Alcmaeon of Croton and then resumed by Galen, who described a melancholic temperament characterized by a black bile excess. This belief was still solid in the sixteenth century, when the French physician Andreas Laurentius related the cause of this pathology to the “coldness and darkness of this humor.” In the nineteenth century, Pinel eventually proposed a new theory discontinuing the connection between humor and black bile and describing four new mental disorders, which included Melancholia and Mania [2]. Kraepelin unified all types of affective disorders in the unitary concept of manic-depressive illness, which included “periodic circular insanities,” “mania,” and “melancholy” [3]. In opposition to this view, Wernicke distinguished five different types of melancholia, going back to taking into consideration the possibility of single episodes of melancholia [4]. Nowadays, the term melancholic represents a subtype of major depressive disorder.