Abstract
Mood disorders are the third most common mental disorder affecting almost one fifth of the general population. Pathological changes of mood were already known to the physicians in the ancient Greece-Hippokrates described melancholia and mania in the 4th century B.C.These terms were also stated in the Galen's works as well as in the Arab and Jewish literature.
The manic-depressive psychosis was only described in the 19th century.