melancholia

n. mental disorder characterized by extreme depression (Psychiatry)

"Melancholy" redirects here. For the anime series, see The Melancholy of Haruhi Suzumiya (anime). Melancholia (Greek μελανχολία), in contemporary usage, is a mood disorder of non-specific depression, characterized by low levels of enthusiasm and low levels of eagerness for activity. In a modern context, "melancholy" applies only to the mental or emotional symptoms of depression or despondency; historically, "melancholia" could be physical as well as mental, and melancholic conditions were classified as such by their common cause rather than by their properties. Similarly, melancholia in ancient usage also encompassed mental disorders which would later be differentiated as schizophrenias or bipolar disorders.
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Melancholia /mel·an·cho·lia/ depression; curently used to denote severe forms of major depressive disorder.melanchol´ic mel·an·cho·li·a n. [more]Melancholia - Community and Resources

Noun
1. extreme depression characterized by tearful sadness and irrational fears
(hypernym) depression

(n.)
A kind of mental unsoundness characterized by extreme depression of spirits, ill-grounded fears, delusions, and brooding over one particular subject or train of ideas.