[Obsessive compulsive disorder and schizophrenia. An attempt at psychopathologic differentiation by focusing on the single phenomenon of obsession].

This paper follows the hypothesis that differentiation between obsessive compulsive disorder and schizophrenia is possible only by focusing on the single phenomenon of obsession. The declaration of a nosological specificity of obsession is set against the current view of ICD-10 and DSM-IV, of obsession as a ubiquitous nonspecific phenomenon appearing with comorbidities. The historic development of these two most different views of obsession and their combination is explained. The distinction between obsessive compulsive disorder and schizophrenia can be made at the psychopathologic dividing line between obsession and delusional thoughts. Examination of the literature on the transition from obsessive compulsive disorder into schizophrenia shows that there is no clear link between obsession and schizophrenia.