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 .
Identification of true drug response to antidepressants. Use of pattern analysis.
The purpose of this study was to develop a method for differentiating specific ( " true " ) and nonspecific antidepressant drug response for the individual patient . Patterns of clinical response , based on weekly global ratings of clinical status , were generated for each of 185 patients participating in six-week placebo-controlled drug trials .  We hypothesized and found that substantially more patients receiving active than placebo medication displayed treatment response patterns characterized both by two-week or greater delay in onset of initial improvement and nonfluctuating persistence of improvement once achieved . Identification of a distinctive pattern of clinical response to an active drug has both research and clinical applications . Pattern analysis may contribute to underst and ing the nature of drug mechanisms of action , may clarify some ambiguous treatment study outcomes , and in the individual case , may facilitate clinical management
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 .