Empirical assessment of the factorial structure of clinical symptoms in schizophrenic patients: Symptom structure in geriatric and nongeriatric samples

Different models of the factor structure of clinical symptoms in chronic schizophrenic patients were compared with confirmatory factor analysis. Samples of geriatric (n = 305) and nongeriatric (n = 240) patients were examined, with the geriatric patient sample divided on the basis of the severity of overall cognitive impairment. Two previous models of the structure of symptoms in schizophrenia were compared to control models. Although there was no evidence that the structure of symptoms varied as a function of the age or cognitive impairment status of the patients, neither model fit the data particularly well. An alternative model was derived on the present sample with exploratory factor analysis, with that model fitting the data somewhat better than the models based on previous studies, but still not adequately according to criteria for goodness of fit of factor structures. These results suggest that symptom structure in geriatric schizophrenic patients does not collapse, either because of symptom burnout or global cognitive impairment, toward a unidimensional organization. An additional implication of these results is that it may not be possible to generate a model using PANSS scores that fits the data adequately, with several reasons for that possibility considered.