What is the main reason of depression?rank them?

Dear neha! In my opinion,there is a hereditarian cause for depression! Everything comes after the main event! Hereditariety is the main cause for depression!The others factors are a consequence! Best regards Cmt Vinil

I honestly think that chemical imbalance in the brain is the number one cause of depression. There is depression after giving birth that is caused by hormones, which are chemicals in the brain. Also illness can play a role that causes long term depression. Chronic pain and chronic fatigue, something that sees no end in sight. All the other things you mention can also cause depression, though I think probably short term. We get over failure in love when we meet someone new. Eventually we learn to live with the loss of a loved one. Job/study/work, you have the power to change those things. Financial problems can be endless if, as in my case, illness is the cause. But if a financial winfall comes along, depression can be lifted (as long as illness is not part of the problem). Failure in exams, family problems, I believe there are ways to get over these, to work on these problems. Wallowing in misery will not help when there are solutions.