5 FACTOR MODEL OF SCHIZOPHRENIA - REPLICATION ACROSS SAMPLES

In order to examine the effect of neuroleptic medication on the factor structure of schizophrenic symptomatology, 517 DSM-III-R schizophreni c in-patients enrolled in a multicenter phase II drug study were evalu ated on their preexisting neuroleptic at screening on the Positive and Negative Syndrome Scale (PANSS) and after a one-week drug-free period . Separate principal components analyses of the PANSS were done at eac h time point. PANSS total and component scores were assessed for diffe rences utilizing paired t-tests. Both factor analyses confirmed the fi ve factor model (negative, positive, cognitive, excitement and depress ion components) explaining 51.7 and 56.2% of the variances at each tim e point. After medication wash-out psychopathology significantly worse ned as measured by total PANSS score and by each of the components. Th e overall worsening of component scores appeared global and uniform, a s evidenced by the fact that at washout, the proportion of individual component scores to total psychopathology remained constant for most c omponents. The lack of change of most components in proportion to the psychopathology total is evidence for the stability of these individua l psychopathological dimensions of patients while on and off neurolept ics. The results further support the validity of the five-factor model of schizophrenic psychopathology as measured by the PANSS.