Depression is recurrent in many cases, so pharmacological treatment of depression needs to be divided into three phases of treatment: the acute phase, the consolidation phase and the maintenance phase (prevention phase). 1. Acute treatment: It is generally considered that at least 6-8 weeks are needed. 2. Treatment in the consolidation phase: It is generally considered to take at least 4-6 months. Note: World Health Organization (WHO): recommended for 6 months or more. American Psychiatric Association (APA): recommended 4-5 months; Royal College of Psychiatrists (RCP): recommended 4 – 6 months 3, maintenance treatment: generally considered to take at least 1 year or more. Note: World Health Organization (WHO): recommended for 2 or more episodes, maintenance treatment for more than 2 years; British Association of Psychopharmacology (BAP): 2 or more episodes, should be long-term maintenance treatment.