Development of Therapist Adherence in Relation to Treatment Outcomes of Adolescents with Behavioral Problems.

Therapist adherence to the treatment manual is assumed to be crucial for adequate implementation and subsequent achievement of the intended, positive treatment outcomes. Although adherence has been mostly studied as a static factor, recent studies suggest that adherence might be dynamic and changes over time. We investigated how parent-perceived adherence to the multisystemic therapy (MST) model develops during treatment and how this development is related to treatment outcomes up to 18 months posttreatment, controlling for the effect of alliance. We used routinely collected data from 848 adolescents (66% male and 76% Western, M age = 15.25 years) and their caregivers participating in MST, a family- and community-based intervention for antisocial adolescents. Adherence and alliance were measured monthly through phone interviews with the caregivers using the Therapist Adherence Measure-Revised. Outcomes were assessed at the end of the treatment and at 18 months posttreatment using the scale Rule-Breaking Behavior of the Child Behavior Checklist and two MST Ultimate Outcomes (i.e., police contact and out-of-home placement). On average, adherence showed an increasing and then flattening slope. The initial level of adherence predicted treatment outcomes at the end of treatment but not at 18 months posttreatment. Change in adherence did not predict treatment outcomes after controlling for alliance. We advocate the need to consider the dynamic nature of adherence in research as well as clinical practice. Change in adherence during treatment, as well as its association with outcome, is likely to be dependent on the adherence measure being used.