Even among those suffering from Depressive Illness, most do not know they have a treatable illness. Most blame themselves and are blamed by others. This leads to the alienation of family and friends who, if they knew of the illness, would be likely to offer support and help find effective treatment. There are probably several causes of Depressive Illness and several different types of depression.
Recent research shows that depression runs in families.
The most severe form, bipolar disorder, is most likely inherited. Certain environmental situations, such as stress or breakup of important attachments, may precipitate depression, especially in vulnerable persons. Research is underway to understand the interaction of genes and environment, and precisely what is inherited.