Depression rarely appears overnight. More often, it builds gradually—through persistent stress, emotional fatigue, unresolved experiences, and subtle shifts in mood, motivation, and energy. Yet many people don’t seek support until their symptoms become severe enough to meet criteria for a formal mental health diagnosis. By that point, daily functioning may already feel overwhelming.

When it comes to depression and sleep, the relationship tends to mimic a chicken-and-egg situation. It can be difficult to tell which one came first and which one followed.