Your therapist wants to know if you believe you can heal your mental illness. Before they take you on as a new patient, a good therapist will make sure you believe you can heal. Without that belief, he or she may be powerless to help you.
God gave us Job's life and story to encourage us. God works the same way in our lives that He did in Job's. Just the illness is different. It's worth noting that this restoration takes work on our part. Our mind heals and becomes sound through the work.
Jesus often required some small act of faith, like stretching out a hand, or getting up to walk, from those he healed. In cases like ours, all he requires is a simple relationship with Him. He requires us to create the life we want. As we do that, His healing forces work in our favor. Over time, he brings about our healing, and we create the life we want to live.