Timing of onset of antidepressant response with fluoxetine treatment.
OBJECTIVE
The purpose of this study was to assess the time until onset of antidepressant response with fluoxetine treatment.


METHODS
The authors evaluated 182 outpatients with major depression who had a sustained acute response to fluoxetine treatment. The outpatients received 8 weeks of treatment with 20 mg/day of fluoxetine and were assessed biweekly with the 17-item Hamilton Depression Rating Scale. The onset of response was defined as a 30% decrease in score on the Hamilton depression scale that persisted and led to a 50% decrease by week 8. The Kaplan-Meier product limit and Cox regression analysis were used to model the relationship between relevant variables and time until onset of response.


RESULTS
The authors found that at weeks 2, 4, and 6, the probabilities of having an onset of response (for responders) were 55.5%, 24.7%, and 9.3%, respectively. The cumulative probabilities of onset of response at each time point were 55.5%, 80.2%, and 89.5%. Neither demographics nor clinical characteristics of depression predicted time until initial response.


CONCLUSIONS
These data suggest that more than half of eventual responders to fluoxetine treatment at 8 weeks start to respond by week 2; over 75% start to respond by week 4. Conversely, the lack of onset of response at 4-6 weeks was associated with about a 73%-88% chance that patients would not have an onset of response by 8 weeks.
Nierenberg
A A
AA
Depression and Clinical Research Program, Massachusetts General Hospital, Boston, MA 02114, USA. anierenberg@partners.org
Farabaugh
A H
AH
Alpert
J E
JE
Gordon
J
J
Worthington
J J
JJ
Rosenbaum
J F
JF
Fava
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D003866:Depressive Disorder / Q000188:drug therapy* / Q000523:psychology; D004334:Drug Administration Schedule; D005260:Female; D005473:Fluoxetine / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D016016:Proportional Hazards Models; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D012720:Severity of Illness Index; D016019:Survival Analysis; D016896:Treatment Outcome
D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors