title: Novel factor-based symptom scores in treatment resistant schizophrenia: implications for clinical trials.
abstract: To study the factor structure of symptoms in patients with treatment resistant schizophrenia and whether it is altered by treatment, we analyzed ratings on the Brief Psychiatric Rating Scale (BPRS) from two independent groups of patients with treatment resistant schizophrenia. With confirmatory factor analysis of pre-clozapine BPRS scores in 1074 patients in an administrative data base, the Clozapine Authorization and Monitoring Program (CAMP), we assessed the fit of published factor models and developed a better-fitting model. Model fit was validated in an independent group of 197 research unit participants. Stability of model fit six months post-clozapine was assessed in 834 CAMP patients. A new 4-factor model (negative symptoms, reality distortion, disorganization, and anxiety/depression) had better fit in both data sets than two commonly used factor models, and also fit better post-clozapine. We recommend these four factor scores as clinical trial outcomes in patients with treatment resistant schizophrenia.
authors.affiliation: Department of Psychiatry, Maryland Psychiatric Research Center, Spring Grove Hospital Grounds, Maple and Locust Avenues, PO Box 21247, Baltimore, MD 21228, USA. rmcmahon@mprc.umaryland.edu
authors.forename: Robert P
authors.initials: RP
authors.lastname: McMahon
authors.forename: Deanna L
authors.initials: DL
authors.lastname: Kelly
authors.forename: Julie
authors.initials: J
authors.lastname: Kreyenbuhl
authors.forename: Brian
authors.initials: B
authors.lastname: Kirkpatrick
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Love
authors.forename: Robert R
authors.initials: RR
authors.lastname: Conley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D003024:Clozapine / Q000627:therapeutic use*; D016208:Databases, Factual; D004351:Drug Resistance; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008396:Maryland / Q000453:epidemiology; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012107:Research Design; D012559:Schizophrenia / Q000188:drug therapy* / Q000453:epidemiology; D012565:Schizophrenic Psychology
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine