God can change a human life. I know this from my own experience, and countless others I've seen change.
The sign of real, God-produced healing is change in behavior and activity. The sign that the blind man was healed is that he could now see "men like trees walking." (Mark 8:24) If this man didn't see the external world while he was walking we'd know he was not healed.
Real healing brings about a change in behavior or activity. Which is what we are praying for. We're not praying for the addicted person to have some dramatic emotional experience, but to be free of their addiction. The prayer is not, "Oh God, make them emotional!" but "Oh God, make them well!"
This freedom will be evidenced by behavioral changes, like the person of 1 John 3:14 who has crossed over from death to life, the evidential sign being that their behavior changes from hatred to love. They have become a loving person, in action.
Healings like this often produce emotions of praise and gratitude towards God. There may be tears. There's nothing wrong with this. But emotional experiences without healing results that lead to behaviorial and attitudinal changes mean nothing. I have seen too many people have an emotional experience without a real healing yet claim they are healed when they are not, since in a day or two they are acting and thinking like their old unhealed self.
Sometimes the emotional experience is used to manipulate other people. They may say, "I've had this powerful, tearful encounter with God! I'm a different person now!" We hope so. We will know so if attitudes and behaviors are different, consistently, over time. The formerly blind person now drives a car and reads books and distinguishes colors and recognizes others by sight. The addict stays clean, over months and years. The promise-breaker now promises and keeps their promises. And we say, "They have been healed - praise God!" (I've seen it happen.)
My new book is Praying: Reflections on 40 Years of Solitary Conversations with God.