Residual Symptoms in Depressed Patients After Treatment With Fluoxetine or Reboxetine

Background: Residual symptoms are common and have a variety of consequences in depressed patients who respond to treatment, but seldom have specific residual symptoms been assessed. We examined the frequency and severity of residual depressive symptoms in 2 studies comparing the selective serotonin reuptake inhibitor (SSRI) fluoxetine with the norepinephrine reuptake inhibitor (NRI) reboxetine.

Method: Data from two 8-week, previously published, double-blind, random-assignment studies comparing fluoxetine and reboxetine were obtained. Both studies included men and women who met DSM-III-R criteria for unipolar nonpsychotic major depression. Symptoms were assessed with the 21-item Hamilton Rating Scale for Depression (HAM-D). The frequency and severity of residual symptoms were determined in the patients who completed treatment and responded (had at least 50% improvement on the HAM-D).

Results: In study 1, 117 patients completed treatment and responded. In study 2, 113 patients completed treatment and responded. The most frequent symptoms present after treatment were psychic anxiety, lack of interest, somatic anxiety, and depressed mood. No residual symptom differed significantly between treatment groups in both samples. Ordinal logistic regression, used to control for baseline symptom severity, revealed no other differences between drug groups except that decreased libido was significantly greater with fluoxetine in study 1 and study 2. Three composite scores for residual anxiety, sleep disturbance, and reduced drive did not differ between drug groups.

Conclusion: This study found no differences in residual symptoms in depressed patients who responded to treatment with the SSRI fluoxetine and the NRI reboxetine, with the exception that the fluoxetine group had a greater decrease in sexual interest, a likely side effect of that drug.