Quelle obscure folie d'avoir laissé mourir ce que m'offrait la vie.

Giovanni Bellini, Pietà, 1505.

Melancholia (n.) - c.1303, ‘‘condition characterized by sullenness, gloom, irritability,’’ from O.Fr. melancholie, from L. L. melancholia, from Gk. melankholia ‘‘sadness,’’ lit. ‘‘black bile,’’ from melas (gen. melanos) ‘‘black’’ (see melanin) þ khole ‘‘bile.’’ Medieval physiology attributed depression to excess of ‘‘black bile,’’ a secretion of the spleen and one of the body’s four ‘‘humors.’’ Adj. sense of ‘‘sullen, gloomy’’ is from 1526; sense of ‘‘deplorable’’ (of a fact or state of things) is from 1710.

The precision of medical diagnostic terms is essential to establish the reliability and validity of proposed disease states. While the term ‘‘depression’’ is widely used in society, its meaning varies with the user, an attitude best expressed by Alice in Wonderland’s Humpty-Dumpty, ‘‘When I use a word, it means just what I choose it to mean – neither more nor less.’’In psychology, depression represents a decrease in psychomotor activity or intellectual agility. Within neurophysiology, depression refers to a decrease in the brain’s functioning, measured in electrical activity or cerebral blood flow. For the pharmacologist, depression means the decrease in body functions induced by sedatives, soporifics, and anesthetics. In clinical practice, depression describes a normal human emotion, a pathologic state if it is retained too long or too deeply, or a psychopathologic syndrome that may be mild or severe.

A clinical depressive episode may be defined by its associated adverse life events or it may strike a subject without cause.Accepting ‘‘depression’’ as a medical diagnosis is equivalent to accepting ‘‘infection’’ as a definitive diagnostic term in clinical medicine.

‘‘Melancholia’’ has a more precise meaning. As a central organizing model of mood disorder, melancholia is a recurrent, debilitating, pervasive brain disorder that alters mood, motor functions, thinking, cognition, perception and many basic physiologic processes.