Although the causes of depressive illness continue to be a matter of intense research, modern brain imaging technologies suggest the following causes:
Imbalance in Neurotransmitters
Neurotransmitters that are responsible for the regulation of moods, thinking, sleep, appetite, and behavior fail to function properly.
Depressive disorders seem to occur generation after generation in some families.
Combination of Genetic, Cognitive, and Environmental Factors
Trauma, loss of a loved one, a difficult relationship, a financial problem, or any stressful change in life patterns may trigger a depressive episode.