The Depression sometimes runs in families and may be due to heredity, learned behavior or both. Even with a genetic predisposition, it is usually a stressful or unhappy life event that triggers the onset of a depressive episode. While the exact causes of depression are unknown, several factors appear to affect its onset!
The biggest cause of depression are the worries, and not having the ability to be able to visualize its possible solutions, that's when the person begins to enter that state of depression that turns out to be worse, since that way is less likely to arise any ideas.