The effects of milnacipran on social dysfunction
Two recent studies have examined the effect of milnacipran on social adaptation as measured by the SASS. Both have been published exclusively in Japanese but have been presented and discussed in detail in a recent review.43
In one study,44 milnacipran was administered at 50 mg/d, increasing to 100 mg/d (mean final dose 83.7 mg/d) to 45 patients with major depressive disorder for 8 weeks. Significant improvement in the classical symptoms of depression, as measured by HDRS and Beck Depression Inventory (BDI), was observed after 2 weeks, and significant improvement of social dysfunction (SASS) after 4 weeks (Figure 5). After 8 weeks of treatment, 51.1% patients were in remission for depression (HDRS < 7) and 42.2% for social dysfunction (SASS > 35). Nonresponders on the HDRS had no significant improvement in their SASS score at endpoint. There was a significant negative correlation (P < 0.01) between the reduction in HDRS score from baseline to endpoint and the increase in SASS score from baseline to endpoint.
The second study45 included 113 patients, employees, or homemakers with major depressive episodes. Milnacipran was administered at 25–50 mg/d, increasing to 100 mg/d by 2 weeks, and then continuing at this dose for 8 weeks (average final dose 85.4 mg/d). Mean HDRS and Zung Self-rating Depression Scale (SDS) scores were significantly reduced (P < 0.01) from 2 weeks, whereas the SASS was only significantly increased (P < 0.01) from 4 weeks. At endpoint, 67.4% patients were classified as responders (≥50% reduction of baseline HDRS), and 43.0% were in remission (HDRS ≤ 7); 33.3% patients had remission on SASS (≥35 points). There was a significant negative correlation between ΔSASS (baseline to endpoint difference) and ΔHDRS (−0.39 P < 0.01), although the correlation was considerably weaker than between the two depression scales (ΔHDRS and ΔSDS; 0.74 P < 0.01).
Both studies showed significant improvement on the SASS scale from 4 weeks of treatment, whereas a significant improvement on depression scales occurred by 2 weeks. Both studies reported a significant negative correlation between changes in the SASS and changes in the HDRS. This correlation was, however, weaker than that between two depression rating scales. Globally, these data suggest that improvement in social function, as measured by the SASS, may be more difficult and slower to achieve than improvement in classical depressive symptoms.
A recent review of the effect of SNRIs on social function43 mentions an unpublished study that compares the improvement of social function in depressed patients treated with milnacipran (mean dose 83 mg/d) and paroxetine (mean dose 35 mg/d). Milnacipran treatment resulted in a greater number of patients with social remission than treatment with paroxetine.