Dyadic, longitudinal associations among outcome expectation and alliance, and their indirect effects on patient outcome.
Research indicates that patient outcome expectation (OE) correlates with improvement, and that this association may be mediated by better patient-therapist alliances. However, despite OE and alliance being dyadic and dynamic constructs, most research on these direct and indirect associations has assessed these variables from only one dyad member's perspective and at single time points. Addressing these gaps, we used a longitudinal actor-partner interdependence model to first examine OE-alliance associations. Namely, we assessed "actor" effects (relation between each member's OE at 1 session and his or her own next session alliance) and "partner" effects (relation between each member's partner's OE at 1 session and his or her own next session alliance). Second, we tested whether significant actor or partner effects of OE on alliance translated into better patient outcomes (indirect effects). Analyses were conducted at within- and between-dyad levels. Data derived from a generalized anxiety disorder trial in which 85 patients received 15 sessions of either cognitive-behavioral therapy (CBT) or CBT integrated with motivational interviewing. After every session, patients and therapists rated OE and alliance, and patients rated their worry. At the within-dyad level, there were OE-alliance actor effects for both patients and therapists. There was also a within-dyad partner effect; when patients had greater OE at one session their therapists reported better next-session alliances. Finally, all within-dyad effects in turn related to lower subsequent worry. Results reveal ways in which session-by-session fluctuations in both patient and therapist OE translate into better outcomes through their influence on alliance quality. (PsycINFO Database Record (c) 2019 APA, all rights reserved).