Treatment with SSRIs rather than placebo was associated with clinical improvement by the end of the first week of use .
CONCLUSIONS Treatment with SSRIs is associated with symptomatic improvement in depression by the end of the first week of use , and the improvement continues at a decreasing rate for at least 6 weeks
CONTEXT Selective serotonin reuptake inhibitors ( SSRIs ) are often described as having a delayed onset of effect in the treatment of depression .
However , some trials have reported clinical improvement as early as the first week of treatment .
OBJECTIVE To test the alternative hypotheses of delayed vs early onset of antidepressant action with SSRIs in patients with unipolar depression .
Fluoxetine, a Selective Serotonin Uptake Inhibitor, for the Treatment of Outpatients with Major Depression
In a double-blind , placebo-controlled study the authors found that fluoxetine , a potent and selective inhibitor of serotonin reuptake , was an effective antidepressant in moderately depressed , ambulatory out patients . Typical adverse effects reported by patients treated with fluoxetine  included agitation , nausea , fatigue , and insomnia . Compared to imipramine , fluoxetine was associated with fewer complaints of dry mouth , constipation , and dizziness
Treatment with SSRIs rather than placebo was associated with clinical improvement by the end of the first week of use .
CONCLUSIONS Treatment with SSRIs is associated with symptomatic improvement in depression by the end of the first week of use , and the improvement continues at a decreasing rate for at least 6 weeks
CONTEXT Selective serotonin reuptake inhibitors ( SSRIs ) are often described as having a delayed onset of effect in the treatment of depression .
However , some trials have reported clinical improvement as early as the first week of treatment .
OBJECTIVE To test the alternative hypotheses of delayed vs early onset of antidepressant action with SSRIs in patients with unipolar depression .