<qa>  What is the primary purpose of this study?This primary purpose of this study is to assess the efficacy and safety of Effexor XR in preventing recurrence in Chinese patients with recurrent major depressive disorder MDD following a 1-year maintenance treatment after an 8-week acute treatment and a 6-month continuation treatment phases. The study will also collect data on the prevalence and pattern of co-morbid anxiety and somatic symptoms and their impact on the recurrence of depression. 