Illustrating systemic change in family therapy: How therapists' and clients' alliance perceptions codevelop over time.

Research showing that caregivers', adolescents' and therapists' perceptions of the therapeutic alliance become more similar over time has not examined conceptual models, like emotional contagion and interdependence, that are theorized to account for this convergence. Objective: We modeled codevelopment in systemic family therapy to examine mutual influence and shared environment processes among the alliance perceptions of youth, caregivers, and therapists. Method: The self-report version of the System for Observing Family Therapy Alliances (SOFTA-s) was administered after sessions 3, 6 and 9-156 Spanish maltreating families and 20 therapists. Results: Using a triadic version of the repeated measures actor-partner interdependence analysis, a random intercepts cross-lagged panel model, we found significant effects of the shared environment and mutual influence in caregivers' and therapists' alliance scores over time, reflecting emotional contagion. Additionally, (i) therapists' alliance scores at session 6 significantly predicted youth alliance scores at session 9, and (ii) therapist alliance at session 6 significantly mediated the relationship between caregiver alliance at session 3 and youth alliance at session 9, suggesting that therapists bridge the caregiver's and youth's perceptions of the alliance. In successful (compared to unsuccessful) cases, therapists' alliance perceptions at session 6 positively influenced caregivers' alliance perceptions at session 9. Conclusion: Therapist's perceptions of the alliance can bridge differences in alliance perceptions of caregivers and adolescents resulting in greater similarity in alliance perceptions over time.