Psychopharmacology and the Classification of Functional Psychoses 

By Thomas A. Ban and Bertalan Pethö

Four-Dimensional Classification

Delusional Psychoses

It has been recognized that psychogenic paranoid reactions are resistant to treatment and may persist in spite of the administration of antipsychotic drugs. Because by definition a psychogenic reaction has a time limited course, its persistence, especially if associated with further delusional elaborations, indicates that the diagnosis should be changed from psychogenic paranoid reaction to "delusional development" also referred to as "paranoiac development" (Meyer, 1917) or "paranoid psychosis" (Gaupp, 1914a,b, 1938, 1974a,b).

Paranoiac development, one of the six basic reactions described by Adolf Meyer, refers to an anomalous development which depends partly on the person's genetic-constitutional make-up and partly on environmental factors. At first, delusional psychotic development was regarded as a disorder providing for the transition between psychogenic and endogenous psychoses. More recently there has been increasing evidence that delusional psychotic development is a form of chronic delusional psychosis (Clerambault, 1921, 1942).