How Is Depression Different From a Bad Mood?
A mood is a feeling, whereas a depression is a chronic illness. Neither feels good, and both can seem to go on and on -- a mood can persist for hours or days. But depression lasts even longer and is physically harmful.
Moods are important to mental health. When we say someone is in a "good" or "bad" mood, it suggests that what's being felt isn't just a temporary emotion, but that the person's background emotional condition has changed. And just like changing the background on your computer screen can change the way data appears, a changed "background mood" can alter your perceptions of things. Good moods give people a sense of pleasure, while bad moods lead to a feeling of discomfort.
A bad mood that persists can transition into depression if attempts to get back to the person's usual mood are unsuccessful.
