We quote the terms ''depersonalization'' and ''derealization'',, though meaningless in an absolute sens, and feel it is suitable to define them as: ''The diminishing of the feeling of significan experiences (vivencia) of the ego and of the reality''. Theme of the communication: twofold: Remember a frequent omission -with important exceptions- is a lack of focus on the terrible pathos which acquires a certain intensity this syndrome. I have working in this direction since 1960 and specifically since 1988 with a total of 3.592 patients affective and obsessive-compulsive, from which I selected 242, whit ''depersonalization'' and ''derealization'' syndromes, 60 of them clinically severe. As assesed by the clinical phenomenological method. The observation time varied from three monts and nigth and half years. ''Under the auspices of egodistonia with a correct juggement of reality'' in following areas: Environmentally (speak of ''symptom of Tantalus''...). In the disminishing of sense of body. The patient involuntary memory. In the area of thougt. In the area of the perception of time. Independent of those other stress situation which are known to acompany the appea arance of the syndrome of the ''depersonalization'' and ''derealization'' we think that this may produce at times symptoms of post-traumatic stress ess. Therefore, thoug the variable ''depersonalization'' is round in some used scales-too often used-as the time of quantitative measurement (and ''singlaosis'') it is not generally investigated systematically in those qualitative aspects of which we have spoken, nor are those aspects enough in their intensity, in a practical way, which would spare the patient a lot of suffering if detected earlier, enabling an earlier application of intense ansiolytic and antidepressive therapies, which would, at least decrease the acutenese of the syndrome and remove the risk of autolysis.