Usefulness of mirtazapine and SSRIs in late-life depression: post hoc analysis of the GUNDAM study.

Objective: Mirtazapine and SSRIs are widely prescribed as first-line agents for late-life depression. However, evidence for these drugs is mostly based on non-elderly patients. Therefore, we reanalyzed a randomized controlled trial of mirtazapine versus SSRIs for depression in a sub-population of late-life patients.

Methods: A randomized controlled trial was conducted with 141 patients, of whom 41 were elderly, and 100 were non-elderly. This study compared SSRIs and mirtazapine in late-life depression, examined late-onset and early adult-onset separately and compared elderly and non-elderly patients for each drug. Treatment effects and adverse events were assessed using the Hamilton Depression Rating Scale and the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale, respectively.

Results: In late-life depression, mirtazapine showed faster HAM-D total score improvement (3.3 points difference, p = 0.021) and higher improvement in insomnia (1.7 points difference, p = 0.001) and appetite (1.2 points difference, p = 0.020). Similar findings were observed for late-onset depression with the HAM-D total score (4.3 points difference, p = 0.007) and appetite (0.9 points difference, p = 0.004), favoring mirtazapine. Depressive symptoms were generally less improved in late-life depression than in non-late-life depression. Regarding the effect of mirtazapine on appetite, late-life depression showed greater improvement (0.7 points difference, p = 0.008). Nausea and micturition disturbances were more common with SSRIs in late-life depression than in non-late-life depression. In contrast, somnolence was less common in late-life depression with mirtazapine.

Conclusion: The potential usefulness of mirtazapine in elderly patients was demonstrated. The results also showed differences in the treatment response to SSRIs and mirtazapine between elderly and non-elderly patients.