text: what is "phase 3 depression"? my best friend told me he is entering into phase 3 depression and i have no idea what that is and he won't tell me because he doesn't want me to worry. the only thing i could find on it is that it's the maintenance stage of depression. (mind you, this isn't an officially accepted psychological concept, it's a drug treatment concept)  " maintenance phase antidepressant therapy that is prescribed specifically to prevent another episode of depression is called "maintenance therapy." maintenance therapy may be given to people at high risk of developing depression, since depression often recurs:      * once a person experiences a single episode of depression, he or she has a 50% chance of having another.     * with two episodes, the chance of recurrence rises to 70%.     * with three episodes, the chance of developing depression again is 90%.  maintenance therapy is used based on the theory that continuing the medication after an initial episode of depression may prevent or lessen the intensity of a subsequent episode. "