ABCT assumes a reciprocal relationship between substance use and relationship functioning.The model assumes that substance use behaviors impact upon thequality and nature of a couple’s relationship, and that the relationship similarly impacts upon the substance use. Thus, from a systemic perspective, the two domains of function (sub- stance use and the relationship) are interconnected rather than independent. Like BCT, ABCT emphasizes the reciprocal interactions between partners, and assumes that relationship distress and dysfunction are maintained by Interactional rather than individual problems. Several lines of evidence support the view that alcohol use impacts on relationship functioning; data suggesting that relationship functioning impacts on alcohol use are much more limited.