Switching versus augmentation: a prospective, naturalistic comparison in depressed, treatment-resistant patients

(1) To directly compare the effectiveness of switching antidepressants with augmenting them in depressed patients who do not respond to an initial adequate trial and (2) to determine whether there is a decreased likelihood of response to a second switch or augmentation trial in those patients who did not respond to the first intervention for treatment-resistant depression.

In a naturalistic, open-label design, all depressed outpatients (DSM-IV criteria) who were treatment resistant were prospectively assessed. Short- and long-term outcomes of switching versus augmentation were compared using the Clinical Global Impressions scale.

In the acute phase, 37 (50.0%) of 74 subjects responded to 1 of the 2 interventions for treatment-resistant depression. Forty-five percent (N = 17) and 56% (N = 20) of the patients who had their antidepressant switched or augmented, respectively, responded to that intervention. Nearly three fourths (71.4%) of the acute responders maintained their response through 6 months of follow-up. In 18 patients who did not respond to the first switch or augmentation, 9 (50.0%) responded to a second trial.

Switching antidepressants was somewhat less effective than augmentation, although this difference was not statistically significant. For patients who do not respond to an augmentation or switch, our results suggest that a second trial for treatment-resistant depression may be as effective as the first.