At the end of the 19th and the beginning of the 20th century, the Austrian Sigmund Freud, physiologist and psychiatrist, laid the foundations of psychoanalysis as a therapeutic method with his studies and revolutionized the way modern man perceives concepts such as consciousness and sexuality. In Mourning and Melancholia, Freud attempts to shed light on the nature of melancholy. Considering mourning as its normal model, he proceeds with a comparative study of these two states, calculating the deviations and identifying their differences.