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

Patrick D. McGorry, Bruce S. Singh, Sheryl Connell, Dean McKenzie, Raphael J. Van Riel, David L. Copolov

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23 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)367-378
Number of pages12
JournalPsychological Medicine
Issue number2
Publication statusPublished - 1 Jan 1992
Externally publishedYes

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