Although the therapeutic alliance is robustly associated with psychotherapy outcomes,less is known about factors that
influence its development. This study examined the association between baseline patient interpersonal factors and patient-
rated alliance in a randomized trial comparing cognitive-behavioral therapy (CBT) and interpersonal therapy (IPT)for
bulimia nervosa. Using hierarchical linear modeling, early and middle alliance were negatively associated with interpersonal
distress and positively associated with interpersonal affiliation. Middle alliance was also related to treatment group
interactions with rigidity, affiliation, and control. Overall, alliance growth was higher in IPT than CBT. Using group-based
trajectory analysis,three divergent alliance trajectories emerged (high and improving,low and improving, and low and
stable), with group mean differences between two of them in terms of interpersonal distress and hostile-submissiveness.