There are two basic types of major depression .
Depressive episodes can occur alone or alternate with episodes of excited behavior called manic.
In the latter case the illness is not clinical depression and it responds to different medications from those used for clinical depression. The alternating manic-depressive illness is called bipolar disorder , and it is discussed as a separate entry. There is some evidence that heart disease and clinical depression are linked. AIDS may result in depression, also. It is natural to have some depression after a loss such as a death in the family.