Future Grace (1995) and he was writing about despondency. I appreciated this quote:
And it could 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 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.
Some of this is indeed finding fruition in the neuroscience world. We are increasingly discovering ways in which thinking does change neurochemistry. These findings are more and more robust. I am eager to see how this changes with advances in neuroscience applied to the spiritual life.
I have also benefited from this dialog between Justin Taylor, John MacArthur, and John Piper on the issue of discouragement. Not to discount MacArthur's experience, but I think that Piper's is more consistent with reality.