From dysthymia to treatment-resistant depression: evolution of a psychopathological construct.

Dysthymia is a psychopathological construct historically described and often reconsidered through the centuries. Its first description is dated back to 400 b.C., when Hippocrates proposed his theory about the 'black bile' and the melancholic temperament. The concept of dysthymia (dys-, 'ill', thymia-, 'emotions') has been largely elaborated in the XIX and XX centuries by Burton, Cullen, Schneider, Kretschmer, Akiskal and other authors, and recently re-formulated in the various editions of the modern Diagnostic and Statistical Manual of Mental Disorders under different diagnostic labels: neurotic depression, dysthymic disorder, persistent depressive disorder. Beyond the nosology, dysthymia issues some other challenges, including the need for further research to characterise the peculiar pathophysiological framework of this syndrome (compared with major depressive disorder) and to better define evidences about tailored-treatment options and their effectiveness.