A lot of patients are presenting a symptomatology escorted with psychosomatic expressions and daily-life perturbations. The diagnosis of depression is often brought forwards while the clinical observed aspects do not correspond really with the gravity and the consequences of a depression. The video film tries to give a "clinical" and "symptomatical" classification. Later on, the biochemical aspects are explained. The past few years, a lot of new drugs have appeared, with each time another biochemical activity on "specific" receptors.