title: Predicting antipsychotic drug response - replication and extension to six weeks in an international olanzapine study.
abstract: OBJECTIVE
  To use the degree of response after 2 weeks of treatment to predict non-response at 4 to 6 weeks.
  
  
  METHODS
  Post-hoc re-analysis of a large multi-centered double-blind trial including 1996 patients with schizophrenia using receiver-operator curves and logistic regression analyses to predict non-response at 4 weeks and at 4-6 weeks from the percentage BPRS change at weeks 1 and 2. The primary non-response criterion was a less than 25% BPRS reduction from baseline.
  
  
  RESULTS
  A 0% BPRS reduction at 2 weeks predicted non-response at 4 weeks with a positive predictive value of 77.1%; and sustained non-response at weeks 4, 5 and 6 with a positive predictive value of 75.8%. In a secondary last-observation-carried forward-analysis a less stringent cutoff of < or =15% BPRS reduction was associated with an acceptable positive predictive value (75%), with even higher sensitivity (76%).
  
  
  CONCLUSIONS
  Those patients who showed little to no reduction of symptoms at week 2 were unlikely to show even minimal response at weeks 4 to 6. There is increasing evidence that such patients may benefit from a change in treatment.
authors.affiliation: Department of Psychiatry and Psychotherapy, Klinikum rechts der Isar der Technischen Universität München, Ismaningerstr. 22, 81675 München, Germany. Stefan.Leucht@lrz.tum.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Leucht
authors.forename: Syed Ali Raza
authors.initials: SA
authors.lastname: Shamsi
authors.forename: Raymonde
authors.initials: R
authors.lastname: Busch
authors.forename: Werner
authors.initials: W
authors.lastname: Kissling
authors.forename: John M
authors.initials: JM
authors.lastname: Kane
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000627:therapeutic use*; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006220:Haloperidol / Q000627:therapeutic use*; D006801:Humans; D007391:International Cooperation; D016015:Logistic Models; D000077152:Olanzapine; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales; D012372:ROC Curve; D012559:Schizophrenia / Q000188:drug therapy*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D006220:Haloperidol; D000077152:Olanzapine