Compare the Efficacy and Tolerability of the Combination of Aripiprazole and Selective Serotonin Reuptake Inhibitors (SSRIs) Used in Major Depression

This double-blind, placebo-control, fixed dose, randomized study will be conducted at a tertiary clinical setting. Patients over 18 y/o fulfilled DSM-IV criteria for major depression, having a baseline HAM-D score ≧ 14 and a HAM-D item 3 score \< 3 will be recruited into the groups. The study group of patients will receive ten weeks of treatment with a combination of fix-dosed sertraline and aripiprazole. The control group will received sertraline only. The score reduction in HAM-D17, CGI, SF-36 and Brief Symptom Rating Scale (BSRS-50) will be periodically estimated as an efficacy following the use of a SSRIs or and aripiprazole.