How do you heal an adult if his parents have abused him emotionally?

First of all, you've to got to forgive them. Every time the thought comes to mind, forgive them and say, "Lord, fill me with your Holy Spirit and help me to overcome the effects upon my personality because of abusive parents or hurts that I've had in the past." The Holy Spirit can help you overcome everything. There's nothing that God cannot help you to overcome from what you've inherited or what you've suffered because of your past.