title: Early nonresponse to fluoxetine as a predictor of poor 8-week outcome.
abstract: OBJECTIVE
  The purpose of this study was to quantify the proportion of patients who show no response to a fixed dose of fluoxetine after 2, 4, and 6 weeks of treatment and then respond by week 8.
  
  
  METHODS
  In an open trial, 143 outpatients who met DSM-III-R criteria for major depressive disorder were treated with a regimen of fluoxetine, 20 mg/day. The authors analyzed the proportion of patients who had less than a 20% decrease from baseline in their scores on the Hamilton Rating Scale for Depression after 2, 4, and 6 weeks and who went on to have a 50% or greater reduction by week 8. A last-observation-carried-forward strategy was used to calculate conditional probabilities of 8-week response. Kaplan-Meier survival analysis was used to estimate probabilities of response at week 8 given degrees of response at week 2.
  
  
  RESULTS
  Eighty-two subjects (57.3%) who started the trial responded by week 8. Of those subjects who showed no improvement at weeks 2, 4, and 6, the proportions of responders at week 8 were 36.4%, 18.9%, and 6.5%, respectively. The Kaplan-Meier estimate of 8-week response given nonresponse at week 2 was 0.45.
  
  
  CONCLUSIONS
  The proportion of patients with no response to antidepressant treatment by 4 or 6 weeks who responded by week 8 was substantially less than that for subjects who had at least a partial response. Nonresponse as early as week 2 predicted 8-week outcome.
authors.affiliation: Depression Research Program, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Nierenberg
authors.forename: N E
authors.initials: NE
authors.lastname: McLean
authors.forename: J E
authors.initials: JE
authors.lastname: Alpert
authors.forename: J J
authors.initials: JJ
authors.lastname: Worthington
authors.forename: J F
authors.initials: JF
authors.lastname: Rosenbaum
authors.forename: M
authors.initials: M
authors.lastname: Fava
mesh_terms: D000328:Adult; D000553:Ambulatory Care; D003866:Depressive Disorder / Q000188:drug therapy* / Q000523:psychology; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005473:Fluoxetine / Q000008:administration & dosage / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011336:Probability; D011569:Psychiatric Status Rating Scales; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D005473:Fluoxetine