Overview: Depression is NOT caused by a single factor. Rather several factors may contribute to the development of depression. These factors may include genetic, environmental stressors and psychological factors.
Genetic and Biological Factors: Depression has been shown to run in families indicating a hereditarycomponent to the cause of depression. However not everyone with a depressed relative also suffers from depression. This means that although genetics may increase the risk of developing depression, it is not the only cause of depression. Some researchers have suggested that the cause of depression may be a lack of serotonin in the brain. However, more research is needed to determine the validity of this theory and what may cause this neurotransmitter imbalance.
Environmental stressors:Certain environmental stressors such as loss or social isolation have been shown to place individuals at a higher risk for the development of depression. Although these factors may “trigger” a depressive episode, they are not the singular cause of depression. Psychological Factors: Certain personalities traits are at a higher risk for the development of depression. For example, individuals with higher levels of self-criticism and low self-worth. This is due to the negative views they place on themselves and the world. This negative viewpoint reinforces stressful situations leading to higher levels of distress.