I read this book recently and it is excellent. It is written by a Christian. If you know someone struggling with any addiction this book could help you help them or they could read it too but I think you should read it first. This book is mainly about Alcohol and drug addiction but the principles can apply to any addiction.
It is called:
ADDICTIONS A Banquet in the Grave by (Finding Hope in the Power of the Gospel) Edward T. Welch.
They sell it on Amazon too.