AA, founded decades before scientific study of the disease began, views addiction as spiritual corruption, necessitating spiritual house-cleaning as the center of recovery.
Surrender is the key. Surrender to one's spiritual higher power, typically thought of as God, but not necessarily.
The common association of AA with Christianity is imprecise. It more closely parallels Islam, which is founded, specifically, on the surrender (al-'islam) of oneself to the will of God.