The document discusses the history, definition, classification and symptoms of mood disorders. It notes that mood disorders have been described since ancient times and includes descriptions of depression, mania, bipolar disorder and their symptoms. Unipolar disorders involve only depression while bipolar disorders involve both depression and mania or hypomania. The document outlines the DSM-5 and ICD-10 classification criteria and diagnostic features of major depressive disorder, bipolar disorder, dysthymia and cyclothymia.