[The contribution of neuroscience to the concept of mental disorder].

AIM: In this article the contribution of neuroscience to the concept of mental disorder is discussed against the background of biological psychiatry and philosophy of mind. RESULTS AND DISCUSSION: Psychiatric nosology is confronted by similar challenges as every general nosology. Among these are the role of dysfunction versus "normal" function, the fuzzy boundary of health and disorder, the role of subjective suffering and the role of causal mechanisms. In the case of mental disorders, a further issue is that every nosology has to take a stance about what mental processes actually are. In this article, the disorder concepts of the fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5) and of the research domain criteria (RDoC) approach of the National Institute of Mental Health are explained and discussed. Furthermore, it is argued that a sound psychiatric nosology should not be purely descriptive but should also take the causal mechanisms of disorders into account. A recent suggestion, the theory of mechanistic property clusters, is introduced. Taking recent discussion on the philosophy of mind into account, it becomes apparent that the obvious assumption that mental disorders are (nothing more than) disorders of the brain might not be correct: at least this has been suggested by the theory of situated cognition. It is concluded that a sound psychiatric nosology will have to consider contemporary theories of mental disorders; however, such a synthesis has yet to be formulated.