Humor is a basic tone of affection, and as such is a constant feature of the personality traits of durability and relative independence from the situations and by environmental stimuli, is a mood that varies for the same person from moment to time depending on the thoughts and life situations from time to time experienced. Each of us experience some degree of melancholy, sadness, unhappiness, but it takes on pathological traits when fluctuates beyond the limits compatible with the importance of the situation of gratification or frustration experienced by the subject. Mood disorders are a group of psychiatric disorders that have as their predominant feature of the alteration in mood, despite some degree of melancholy is considered normal when it comes to mood disorder and no longer possible to restore an appropriate balance. Although the most common psychological disorders, if not diagnosed promptly and treated appropriately (both psychologically and, when necessary, pharmacologically) mild disturbances can become as disabling. When the mood is set very low, usually defined as ''depressed mood'', the person has a strong daily sadness and an inability to experience the same positive pleasures previously received in making its activities and to perceive more joys from its many spheres of life. It is a psychological condition that causes a real and significant distress or impairment in normal functioning of personal, social, business, academic, family, emotional or in the various areas of life, functional and related to the maintenance of wellbeing general.