Comparison of escitalopram and citalopram in outpatients with severe major depressive disorder: a prospective, naturalistic, 8-week study.

Objective. Escitalopram is a new selective serotonin reuptake inhibitor indicated for the treatment of major depressive disorder (MDD). The objective of this study is to examine its efficacy in the treatment of severe MDD compared with that of citalopram in daily practice. Method. A prospective, naturalistic, 8-week study was conducted involving 127 patients fulfilling DSM-IV criteria for severe MDD and having a baseline Montgomery-Åsberg Depression Rating Scale (MADRS) score of at least 30. A full non-parsimonious logistic model, called the propensity score, was first defined to reduce bias associated with non-randomization. The primary efficacy analysis was the mean change from baseline to week 8 in MADRS score between the escitalopram and citalopram groups, after stratification on the propensity score. Other efficacy measurements consisted of the Clinical Global Impression of Severity and Improvement scales (CGI-S and CGI-I, respectively), response (defined as a reduction of at least 50% on MADRS from baseline to week 8) and remission rates (defined as MADRS ≤ 12 at week 8), after adjustment on propensity score for escitalopram use. Results. A total of 67 escitalopram-treated patients and 60 citalopram-treated patients were enrolled in this study. Escitalopram reduced mean MADRS total score at week 8 compared with citalopram (-23.5 vs. -17.5; P<0.001). The effect of escitalopram was consistently greater than that of citalopram on the CGI scales. Escitalopram-treated patients were also more likely to respond to treatment (79.4 vs. 44.0%; P<0.001), and remission rates were also in favour of escitalopram (56.9 vs. 11.2%, P<0.001). Analysis of safety data showed better tolerability of escitalopram than that of citalopram. Conclusion. Using adequate methodology to reduce biases due to non-randomization, this study indicates better efficacy and tolerability of escitalopram versus citalopram in severe MDD outpatients.