Alcohol expectancy mediation of biopsychosocial risk: complex patterns of mediation.

Alcohol expectancies' mediation of many known antecedents' influence on drinking has been well established, but most models have omitted theoretically relevant mediational pathways through both common (overlapping) and unique (nonshared) expectancy variance. The authors of this study evaluated expectancy mediation using a hierarchical expectancy model that specified both common and unique expectancy factors. The hierarchical model mediated a significantly (p <.05) larger percentage of the antecedent influences than a model specifying only common expectancy variance, revealed previously unseen mediational paths, and showed, to the authors' knowledge for the first time, expectancy mediation of protective as well as risk-related antecedents. It also allows the modeling of specific pathways for particular antecedents, rather than treating all expectancy mediation as though it flows through a general expectancy factor.