 Exclusion criteria:1.Hypersensitivity to venlafaxine;2.Received venlafaxine treatment before;3.Clinically significant renal or hepatic disease or any other medical disease that, in the opinion of the investigator, might compromise the study, including seizure disorder with the exception of a single childhood febrile seizure; 4.Alcohol or drug abuse within the last year;5.A recent history of myocardial infarction or unstable heart disease within 6 months of baseline;6.Bipolar disorder;7.For female, known or suspected pregnancy or breast feeding;8.Use of a monoamine oxidize inhibitor MAOI within 14 days of baseline; use of any investigational drug within 30 days of baseline. 