A continuous feeling of sadness could be just a dark mood, or it could be persistent depressive disorder that lasts for a long period of time. Persistent Depressive Disorder, or PDD, is not as severe ...

With fewer symptoms and less severe presentation, persistent depressive disorder (PDD) differs from clinical depression. If ...

You could have what some people call "high-functioning depression" if your symptoms don't have a major impact on your daily ...

DEAR MAYO CLINIC: How is seasonal affective disorder diagnosed and treated? Seasonal affective disorder (SAD) is a type of depression that occurs during the winter months. Although exactly what causes ...