This document discusses depression in teens, providing an example of how stress can develop into depression if left unaddressed. It begins with an example of a teen (Teen B) becoming stressed because a friend is going on a trip. Over time, as Teen B's negative thoughts continue without improvement, his stress develops into depression. The document then outlines 5 levels of depression according to symptoms, using the example of Teen B to illustrate how his condition worsens through each level until he attempts suicide, showing severe level 5 depression. It emphasizes that levels 4 and 5 depression require immediate professional help.