The medical model says that we are addicted to chemicals. It says that brain chemistry, neurotransmitters, receptor cells etc. are at the root of the problem. Yet the addiction model does not explain how some people are able to stop an addictive pattern without medical intervention while others struggle desperately for decades. If the addiction model was correct then once someone had successfully withdrawn from an addictive substance then they should be free from the habit for the rest of their life. And yet it is not uncommon for stress to kick off the habit once again.
Look at inner conflict from an NLP perspective. We start by having the client acknowledge that there is a part of them that wants to stop a behaviour and a part that wants them to