Depressive disorders belong to the group of the so-called mood disorders (affective disorders), which includes the bipolar disorders, the cyclothymia and dysthymia. There are several criteria by which one can distinguish the different types of mood disorders and depressive disorders:
Single depressive episode or recurrent disease
We distinguish the depressive disorders according to whether they occur as a single episode or as recurrent disease with recurrent depressive episodes. About half of all people who develop a first depressive episode experience a recurrence of the disorder in the following months or years.
Unipolar or bipolar disorder
The depressive disorders are distinguished in so-called unipolar depression (exclusively episodes with depressive symptoms) and bipolar disorders (with episodes of depression alternating with manic or hypomanic episodes).
The individual depressive episodes are - according to their severity - distinguished into mild, moderate or severe depressive episodes. This has, among others, consequences for the treatment, since the choice of treatment methods is largely based on the severity of the depression. If the disease persist over many years with only slight symptoms, we also speak of a dysthymia or of cyclothymia.