RESUMEN
Studies that employ multidimensional attachment measures to explore the impact of attachment style on psychotherapy process and outcome are virtually absent in the literature. Further, the role of the working (therapeutic) alliance as a mediator of the influence of attachment on treatment outcome has not been formally investigated. In order to address these gaps in the research, archival data from 66 psychotherapy clients treated at a university graduate program training clinic were used to examine the influence of three adult attachment dimensions (Comfort with Closeness, Comfort Depending on Others, and Rejection Anxiety) on the therapeutic alliance and outcome, as well as to assess whether the alliance mediates the relationship between attachment and therapy outcome. Both Comfort with Closeness and Comfort Depending on Others were significantly related to alliance and outcome, whereas Rejection Anxiety was not significantly related to either variable. Alliance was a significant partial mediator of the effect of Comfort with Closeness on outcome. The results suggest that multidimensional measures of attachment capture important influences on alliance and psychotherapy and that Comfort with Closeness promotes successful outcome by virtue of its influence on alliance.