The Theology of Addiction

Can a Christian be an addict? Yes and no. Yes in that many Christians have besetting sins, i.e. sins that they just cannot seem to be able to mortify/repent of. To clarify this "yes" and "no" statement let me say that one that does not seem to be bothered with being in such a condition is not really a Christian. A true Christian cannot rest with the matter of sin but on the contrary always struggles at overcome it. So in this context the answer is no.
There are some sins that are life controlling sins/addictions. Because of the noetic effects of sin the brain does not function as it should. We are "sick." We are "diseased." The medical community is replete with information that supports the notion of a brain malfunction, if you will, when it comes to addictions.
Indeed I would say that every sin rests on a defect in our brain/thinking/reasoning.
The medical field corroborates the fact that we are sometimes genetically predisposed with certain inclinations they call illnesses or disorders e.g. chemical dependency (alcohol and drug addiction), sexual addiction, gambling, and eating disorders . This is nothing new to the Christian. We call it original sin. Addictions are indeed diseases of the brain--a fallen brain! Sin has infected the thought process. This is true on both a physiological and spiritual level.
How do we overcome such addictions? We overcome them by using whatever means are necessary and at our disposal both spiritually and clinically. To have true "recovery" though "treatment" must be God centered.
There are many who have overcome addictions apart from faith in Christ , but miss the boat eternally. This is both good and bad. The fact of the matter is that addiction is sin and the only true way to get rid of sin is to bring it to God for disposal. Otherwise one only washes the outside and not the inside--eternally speaking.
"Bless the Lord...who forgiveth all thine iniquities; who healeth all thy diseases; who redeemeth thy life from destruction (Ps. 103:1-4).