Motivation to Change, Therapeutic Alliance and Outcome-A Complex Interaction in Patients With Anorexia Nervosa.

OBJECTIVE: The role of the therapeutic alliance (TA) in treatment outcomes of anorexia nervosa (AN) appears to be less substantial than in other disorders. However, the therapeutic process is a complex trajectory with many variables influencing each other. Hence, investigating motivation to change in the bidirectional interplay between TA and outcome among patients with AN may enhance the understanding of these processes. METHOD: In an exploratory analysis of longitudinal data from 173 inpatients with AN assessed at four time points in a specialized in-patient clinic, the interplay of TA and its subscales with motivation was investigated using cross-lagged panel models. Additionally, motivation was tested as a possible moderator and mediator of previously examined relationships between outcome and TA. RESULTS: Autoregressive paths of TA and motivation were highly stable over the course of treatment, while residual covariances varied. Motivation showed moderate but significant cross-lagged effects on subsequent TA, while TA had no effect on subsequent motivation. These associations were observed only when motivation was assessed with an exploratory measure of motivation. No mediation and moderation effect of motivation on relationships between TA and outcome was found. DISCUSSION: Cross-lagged analyses suggested that motivation preceded subsequent levels of TA, whereas TA did not predict subsequent motivation. Given the exploratory nature of the study, these findings should be considered hypothesis-generating and require replication. Future research using more fine-grained methodologies may help to further elucidate the longitudinal interplay between motivation and TA in patients with AN.