Since 1863 psychiatry is dominated by the nosological conceptual paradigm that was further stimulated by the introduction of the DSM-III. This has resulted in an ignorance of the European psychiatric diagnostic tradition and a loss of the necessary critical observations and descriptions of psychopathology. This unfortunate process may be observed in the diagnosis of psychiatric disorders in mentally retarded patients where entities such as atypical psychoses, unstable mood disorder and motivational deficit syndrome are not recognized in general. The enormous increase of neuroscienti-fic knowledge, particularly the impact of genetic and intracellular mechanisms in the pathophysiology of psychiatric disorders, warrants the use of a more dimensional and functional psychiatric paradigm. It concerns the effect of gene transcription on the expression of neurotransmitters and receptors that may account for an increased vulnerability or a relapsing course. A so called anticipatory treatment approach is therefore advocated.