The understanding and classification of persistently depressed mood has undergone many changes since the term ‘dysthymia’ was first used nearly 150 years ago. Originally it was applied to both melancholia and mania; later it was applied to depressive personality. The Diagnostic and Statistical Manual (DSM)-III in 1980 and in subsequent updates classified dysthymia as a mood disorder, characterized by a frequently insidious onset and a course that is chronic and unremitting. The assessment of clinical response in the pharmacologic treatment of dysthymia has been more difficult than that for major depression. The Hamilton Rating Scale for Depression, among others, is oriented towards episodic rather than chronic states of depression. A new rating scale, the Cornell Dysthymia Rating Scale, has been developed to better assess milder symptomatology in chronically depressed patients. Early studies suggest its utility, but further validation of the scale is needed in patients with dysthymia and without major depression.
