Data were identified by searches of Medline (1966 to September 2009) and references from relevant articles and books. Search terms included depression, antidepressant, predictor, response, onset, acceleration, and augmentation. As our focus was on the acute phase treatment of depression, articles relevant to treatment-resistant depression were excluded. Only articles written in English or Japanese were consulted.
Studies, reviews, and books pertaining to the treatment of depression with a special regard to accelerating therapeutic effects were selected.
Most of the available treatment guidelines for major depressive disorders recommend the continuous use of antidepressants for 4 to 8a0;weeks based on the idea of a delayed onset of response to these drugs. Contrary to this conventional belief, the recent data indicate that antidepressants start to exert their effects within 2a0;weeks and early non-response could predict a subsequent unfavorable outcome.
These findings suggest the need of revisiting the timing of an antidepressant switch for early non-responders, whereby switching could be commenced in as early as 2a0;weeks.