Statistical analysis
The safety set included all study participants who received at least one dose of open-label study medication. The change in the severity of depressive symptoms was evaluated in study participants in the safety analysis who had been subjected to at least one post-open-label baseline evaluation [observed case (OC) data set]. Safety and efficacy data were summarized using descriptive statistics. The results were tabulated for all study participants enrolled in the open-label extension phase. Data were analyzed using the SAS System, version 9.1.3 (SAS Institute, Cary, North Carolina, USA).