what does Bible say about depression?How we can overcome

In my view, I believe there are basically  three main causes to most feelings of depression: spiritual, circumstantial, and biological. A depression linked to the spiritual side of our lives might be present because something is wrong with our personal walk with God, we might feel guilty for a sin we committed, or perhaps we are even going through a season of spiritual warfare. For example, when you read Psalm 32:1-5, you can see how sin can cause us depression and thus God’s grace is the solution we need:

Blessed is the one whose transgression is forgiven, whose sin is covered. Blessed is the man against whom the Lord counts no iniquity, and in whose spirit there is no deceit. For when I kept silent, my bones wasted away through my groaning all day long. For day and night your hand was heavy upon me; my strength was dried up as by the heat of summer. I acknowledged my sin to you, and I did not cover my iniquity; I said, ‘I will confess my transgressions to the Lord,’ and you forgave the iniquity of my sin.” While our connection with God is the true source of joy, being connected to God by the grace of Jesus does not mean you will never experience any type of depression. Another source of depression can be events and circumstances in our lives.

When you are sad about something that you should be sad about, this means your heart is working properly. If your child dies, for example, a deep depression would be very appropriate. If you have been diagnosed with cancer, a feeling of depression is natural. Even in the midst of trials likes these, however, we can still have joy in the Lord.