Battling Despondency

Adapted from John Piper's book Battling Unbelief:

"What then is the root of despondency? Lloyd-Jones would agree that it is an oversimplification to say that the single root of despondency is unbelief. But it would be right to say, as Lloyd-Jones does say, "The ultimate cause of all spiritual depression is unbelief." For example, where did the kind of parenting come from that sanctions pouting? Did it come from a strong belief in the Word of God as the best book on parenting? And why do so many people pursue nighttime activities that guarantee fatigue which leads to despondency and irritability and moral vulnerability? Is it owing to a strong belief in God's counsel to get good rest (Psalm 127:2) and a firm trust in his power to work for those who wait for him (Isaiah 64:4; Psalm 37:5)?

And could it be that brain research is in such infancy that even though we know a little bit about how chemicals can produce emotional states, we know almost nothing about the ways emotional and spiritual states may produce healing chemicals? Could anyone disprove the possibility that being satisfied with all that God is for us in Jesus has no physical effect on the body's production of natural antidepressants? Why should we not assume that the powerful affection of faith in future grace promotes even physical means of mental health? My own conviction is that when we get to heaven we will learn some astonishing things about the profound connection between sound faith and sound minds."

Desiring God