What are the causes of depression? what about postpartum depression?

Quite Complex!: Mood disorders are very complex -quite often it may be situational, more often than recognized, "in the family" or genetic. Nutrition, hormones, undesired life changes, loss of a loved one -even a pet can send your outlook and persona down to the negative numbers. Even the best swimmers sometimes need help getting ashore. Depression, while complex, is treatable. Lots of initial self-screen on web.

Exact causes unknown: Multiple factors are often involved including dramatic hormonal changes following delivery when estrogen and Progesterone drop to levels similar to pre-pregnancy.