For most people who suffer from depression:

A) the depression remains permanently.
B) each episode of depression lasts under one week.
C) depression is likely to return after the initial episode.
D) it takes a lot of stress to trigger an episode of depression.

Depression

A common and serious medical illness that negatively affects how you feel, the way you think, and how you act, characterized by feelings of sadness, loss of interest in activities, and a variety of emotional and physical problems.

Initial Episode

The first occurrence or manifestation of a situation, condition, or series of events.

Permanent

Having the quality of lasting indefinitely without change or decay.