Psychological Medicine

Original Articles

Diagnostic concordance in functional psychosis revisited: a study of inter-relationships between alternative concepts of psychotic disorder

Patrick D. McGorrya1 c1, Bruce S. Singha1, Sheryl Connella1, Dean McKenziea1, Raphael J. Van Riela1 and David L. Copolova1

a1 National Health and Medical Research Council Schizophrenia Research Unit, Royal Park Hospital, Melbourne, Australia


More than a decade ago, a series of retrospective studies examined the concordance between proliferating definitions of severe psychiatric disorder. The European response has been a polydiagnostic one, which has attempted to maintain interest in a broad range of psychiatric phenomena in the psychoses. In North America a more convergent approach has emerged, resulting in a series of operational definitions evolving from one another, and a correspondingly limited capacity to allow alternative perspectives to co-exist. The present study uses a prospective design as well as recent improvements in the clinical validity of psychopathology assessment to re-evaluate the relationships between competing concepts of psychotic illness in a broad sample (N = 176) of recent-onset psychotic patients. In the schizophrenic group, concordance was predictably highest among recent North American ‘cousins’, and lowest among various historical concepts. There was a moderately high concordance between selected schizoaffective and atypical psychosis definitions, indicating that this component is an important area for further studies of descriptive validity. These interrelationships may be used as a starting point to explore latent classes underlying the phenomena of functional psychosis.


c1 Address for correspondence: Dr P. D. McGorry, NH & MRC Schizophrenia Research Unit, Royal Park Hospital, Private Bag 3, parkville, victoria 3052, Australia.