Depressive disorders (unipolar depression) are mental illnesses characterized by a profound and persistent feeling of sadness or despair and/or a loss of interest in things that once were pleasurable. Disturbance in sleep, appetite, and mental processes are a common accompaniment.
Two Main Categories
1. Major depressive disorder is a moderate to severe episode of depression lasting two or more weeks. Children experiencing a major depressive episode may appear or fell irritable rather than depressed. In addition, five or more of the following symptoms will occur on an almost daily basis for a period of at least two weeks:
2. Dysthymic Disorder is an ongoing, chronic depression that lasts two or more years (one or more years in children) and has an average duration of 16 years. The mild to moderated depression of dysthymic disorder may rise and fall in intensity, and those afflicted with the disorder may experience some periods of normal, non-depressed mood of up to two months in length. Along with an underlying feeling of depression, people with dysthymic disorder experience two or more of the following symptoms: