THE DIMENSIONS OF SCHIZOPHRENIA PHENOMENOLOGY - NOT ONE OR 2, AT LEAST 3, PERHAPS 4

Background. This confirmatory investigation examined the underlying st ructure of schizophrenia phenomenology through examination of the fit of several prominent dimensional models to observed symptom data. Meth od. Confirmatory factor analysis was conducted on a correlation matrix of schizophrenia signs and symptoms derived from case history ratings of 192 individuals with schizophrenia who were the subjects in the ma jor twin studies of schizophrenia. Results. Schizophrenia phenomenolog y appears best described by four underlying factors, namely negative s ymptoms, premorbid social adjustment deficits, reality distortion, and disorganisation. Of interest, the premorbid deficit dimension was dir ectly associated with negative symptoms and disorganisation, but was i nversely associated with reality distortion. Conclusions. These data c learly support the multidimensionality of schizophrenia phenomenology and provide objective support for a four-factor model over other model s. This four-factor model may be useful in organising existing and fut ure data concerning the genetic, neurobiological, neurological, and ps ychosocial features of schizophrenia.