title: [Methodologic and strategic considerations in schizophrenia research].
abstract: So far, schizophrenia can only be regarded as a heterogeneous syndrome in view of the fact that both concept and phenomenology themselves are heterogeneous and also that aetiology and pathogenesis are likewise largely unknown. Furthermore, the diagnosis "schizophrenia" is merely a convention and nothing more, which, in turn, considerably hampers aetiopathogenetic research. Hence, we cannot expect highly valid results if we examine the nosological specificity of certain variables by means of internosological comparisons. However, a clinically more relevant approach could be the examination of the clinical validity especially the prognostic and predictive validity of variables, even though such examination has so far not led to convincing results in individual cases. A more striking relevance for aetiopathogenetic groupings could be obtained, above all, by a "reversal of the dependence of variables". This reversal should concern variables that are as homogeneous and clearly defined as possible and are reliably measurable. This applies mainly if by "horizontal" characterisation a) they have proved to be time-stable trait markers on the grounds of prospective intraindividual comparisons; b) furthermore, if by being present before the diseased state is manifest they have proved to be vulnerability markers either retrospectively by anamnesis of relevant signs and symptoms or prospectively in still (?) healthy subjects by means of high-risk studies; c) and, finally, if they are found to be markers in the true sense of the word on the grounds of their mass occurrence in healthy blood relatives, i.e. as variables under genetic control. We think that mainly such variables appear to be promising for an aetiopathogenetically oriented "vertical" strategy. This strategy aims via multidisciplinary multilevel analyses, utilising strategies, techniques and results of the rapidly developing neurosciences, at establishing connections of variables between various levels, as the "uppermost" of which we can consider to be the clinico-psychopathological level and as "lowermost" the molecular-biological level. This is discussed on the basis of examples.
authors.affiliation: Direktor der Psychiatrischen Klinik u. Poliklinik, Berlin.
authors.forename: H
authors.initials: H
authors.lastname: Helmchen
mesh_terms: D006801:Humans; D012106:Research; D012559:Schizophrenia / Q000209:etiology*; D012565:Schizophrenic Psychology
vernacular_title: Methodologische und strategische Erwägungen in der Schizophrenie-Forschung.