[Psychotic disorders: the need for staging].

Background: In psychotic disorders it is the stage of development of the disease which mainly determines the prognosis and the effectiveness of treatment.
Aim: To describe and to refine the current staging and profiling of psychotic disorders and to propose a way in which to describe the course of dimensions of psychoses.
Method: We searched the literature for articles relating to the staging of psychotic disorders.
Results: McGorry e.a. developed a simple classification into stages which is currently applicable to research and clinical practice. We propose a further refinement in the form of a graph from which one can see in a glance the history of clinically relevant variation.
Conclusion: Research into the prodromal stages of diseases is needed in order to elucidate the pathophysiological mechanisms that the stages have in common and to reveal the pathways of differential development.