This stigma gets in the way of obtaining needed treatment. Only a minority of severely depressed patients are ever treated, and only a minority of them receive adequate treatment. This tragic state of affairs means that both the general public and their doctors must improve their understanding of depression. We know that depressive illness runs in families and that women are particularly vulnerable. However, depression often occurs sporadically, with no evidence that any family member ever had the illness.
Some medications can precipitate a depression.
It is clear that many depressions are triggered by stress or loss. But this is not a complete explanation since only a small proportion of people experiencing stress or loss develop depressive illness. Since there are no objective diagnostic tests for depression and since it often comes and goes, there are many conflicting theories about treatment that report wonderful results. However, the mere fact that somebody gets well after any particular treatment does not prove that the treatment works, since they may have improved despite the treatment, rather than because of it. Determining whether a treatment really works requires complicated studies known as clinical trials.