Background: There is a paucity of naturalistic studies from depression specialty clinics describing the next-step (augmentation versus switching) practices of clinicians for outpatients with major depressive disorder (MDD) resistant to an antidepressant trial of adequate dose and duration.
Methods: Eighty-five MDD outpatients enrolled in one of two specialty clinics, who had not achieved remission after a first adequate prospective antidepressant trial conducted at the clinic underwent either augmentation (n = 36) or switching (n=49) of their antidepressant regimen. Outcome was defined with the use of the Clinical Global Impressions (CGI) Scale.
Results: Nonresponders (CGI-I>3) following the first antidepressant trial were more likely to have their treatment switched than patients who experienced incomplete response (CGI-I<4, CGI-S>1) (67.2% versus 28.5%, p = 0.001). Incomplete responders during the first trial who went on to receive augmentation had higher remission rates (60.0% versus 0%, p=0.01), lower endpoint depression severity scores (1.8 +/- 1.1 versus 3.3 +/- 0.8, p = 0.01) and greater clinical improvement scores (1.6 +/- 1.1 versus 3.0 +/- 0.0, p=0.03) than incomplete responders who had their antidepressant regimen switched. Although nonresponders to the first treatment who were switched experienced greater symptom improvement than nonresponders who were augmented (2.7 +/- 1.1 versus 3.4 +/- 1.2, p=0.03), there was no significant difference (p>0.05) between these two groups with respect to remission rates (18.6% versus 14.2%, respectively) and endpoint depressive severity (3.0 +/- 1.4 versus 3.4 +/- 1.4, respectively).
Conclusions: In this nonrandomized, naturalistic treatment setting, nonresponders to an adequate, prospective antidepressant trial were more likely to have their antidepressant regimen switched, while patients with incomplete response during the first trial were more likely to have their regimen augmented. In addition, patients with incomplete response who had their treatment augmented had better outcome than patients with incomplete response who had their treatment switched.