There has been little investigation of the effect of neuroleptic medication on the structure of symptoms in schizophrenia. In this study, 135 male schizophrenic patients were rated with the Brief Psychiatric Rating Scale (BPRS) after 4 weeks of treatment with typical neuroleptic medication and after 2 weeks free of neuroleptics, with the order of assessment varying across patients. Confirmatory factor analyses (CFA) found that there were no differences in symptom structure across medication status and no differences in the structure of symptoms in treatment responders and nonresponders.

Harvey PD, Davidson M, White L, Keefe RSE, Hirschowitz J, Mohs RC, Davis KL. Empirical evaluation of the factorial structure of clinical symptoms in schizophrenia:  Effects of typical neuroleptics on the Brief Psychiatric Rating Scale. Biological Psychiatry, 1996; 40(80): 755-760.