Antidepressants: can we determine how quickly they work? Issues from the literature

Published reports of antidepressants in clinical trials were reviewed by conducting a literature search focusing on the time period between 1969 and 1994; 240 English-language articles were identified. In these, considerable variation was noted in how study data were evaluated. A few particular points of view concerning antidepressant speed of onset were abstracted. These demonstrate that both antidepressant and placebo treatment of depressed patients are associated with measurable clinical activity during the first weeks of therapy. Methods currently exist to determine speed of antidepressant onset. However, at least one proposed method (Quitkin's pattern analysis) has not yet identified any fast-acting antidepressants. Further work is needed to refine the methods of studying antidepressant onset of action. It is most important that antidepressant drugs with early, clinically relevant onset of activity be identified.