In this paper, some difficulties connected with the notion of 'mental illness' are presented. Firstly, the author concentrates on the conditions necessary for creating a good definition of mental illness and demonstrates the presence of two groups of criteria, which are in opposition to one another and cannot be reconciled. Next, relating to 'conceptual map' of mental disorders (following B. Fulford), common characteristics of psychiatric conditions are sketched out. On the basis of these analyses, the sources of such a diversity of perspectives on mental illness are located (from biomedical model to anti-psychiatry movement). The author points out that these definitional problems stem from accepting the implicit model of physical illness and the hope for naturalization of psychopathological disorders. The limitation of this biomedical perspective is presented by promoting the thesis that mental illness is a kind of metaphor. However, the consequences of such assumptions are different than those of Thomas Szasz' sceptic position. It means that the trouble with the concept of mental disorder is part of the dynamics of scientific research and discoveries and especially medical practice, where extra-theoretical factors are important part supporting official theories and therapeutic methods.
