• Major Depression-This is the most dangerous or solemn type of depression, in terms of number of symptoms and severity of symptoms, but there are significant individual differences in the symptoms and severity. You do not need to feel suicidal to have a major depression, and you do not need to have a history of hospitalizations either, although both of these factors are present in some people with major depression. There is no official diagnosis of "moderate depression."
• Dysthymic Disorder- This refers to a low to moderate level of depression that persists for at least two years, and often longer. While the symptoms are not as severe as a major depression, they are more enduring and resistant to treatment. Some people with dysthymia develop a major depression at some time during the course of their depression.
• Unspecified Depression - This category is used to help researchers who are studying other specific types of depression, and do not want their data confounded with marginal diagnoses. It includes people with a serious depression, but not quite severe enough to have a diagnosis of a major depression. It also includes people with chronic, moderate depression, which has not been present long enough for a diagnosis of a Dysthymic disorder.
• Bipolar Depression- This type includes both high and low mood swings, as well as a variety of other significant symptoms not present in other depressions.