UCLA

Treatment engagement challenges are among the most persistent barriers to effective youth mental health treatment, with a substantial proportion of youth and families terminating services before achieving expected clinical gains (Becker & Chorpita, 2023). Despite growing recognition of the multidimensional, dynamic, and transactional nature of treatment engagement, relatively little is known about the within-session therapist behaviors that may occur in the context of and inadvertently contribute to engagement challenges. This dissertation examined therapist “missteps,” or inadvertent, less optimal, or noncollaborative therapist behaviors, across two studies using observational data from the Reaching Families Study, a multisite cluster-randomized trial focused on improving use of evidence to target low treatment engagement in publicly funded youth mental health settings (Chorpita et al., 2025). Study 1 sought to first understand how therapists misstep by examining the occurrence of missteps across several key contextual factors, including session composition, the recipient of the misstep, and the surrounding in-session therapist behaviors. Therapist missteps were prevalent, occurring in over half of recorded therapy sessions with an average of approximately 2.5 missteps per session. In family sessions, missteps were most frequently directed at the youth. Advice-giving emerged as the most prevalent type of therapist misstep to occur across all session types. Descriptively, approximately 38.1% of observed missteps occurred following another misstep occurrence (10.6%) or in the absence of an identifiable evidence-based technique (27.5%). These findings suggest that missteps may be a common occurrence when delivering care, particularly in the context of engagement challenges, and may be more vulnerable to occur during unstructured or uncertain moments in a session. The first study also sought to examine when therapists may misstep by examining associations between misstep occurrences and factors related to therapist preparedness. Findings suggest that neither the timing of supervision relative to treatment nor the presence and quality of a treatment plan established for the session were credibly associated with total misstep frequency. These findings converge with later findings in Study 2, which indicated that the presence of a treatment plan did not appear to moderate the relationship between misstep frequency and average practice extensiveness, an aggregate indicator of the overall quality of treatment delivered in the session. Together, these findings suggest that identifying what to do in the next session alone may not be sufficient in supporting therapists from engaging in inadvertent missteps. However, provision of comprehensive, coordinated decision-making supports for the detection, identification, and targeted intervention of engagement challenges (i.e., the Coordinated Knowledge System, CKS) was associated with substantially lower expected misstep rates in Study 1. This robust effect remained in exploratory analyses even after accounting for the therapist’s optimal practice quality in the session (i.e., the maximum practice extensiveness across all practices delivered in the session). Study 2 extended these findings by examining what happens in the therapy session when missteps occur. Misstep frequency was credibly associated (i.e., in Bayesian estimation, displaying sufficient evidence that the effect is real and in a consistent direction given the posterior distribution of the parameter) with the therapist’s overall treatment quality for the session (i.e., average practice extensiveness) in the originally proposed analyses, however, the credible interval marginally excluded zero and should be interpreted with caution. Exploratory analyses using the therapist’s maximum practice extensiveness revealed a credible association with misstep occurrences, in which increases in the therapist’s practice quality were associated with decreases in misstep occurrences in the session. Misstep occurrences were also credibly associated with a modest decrease in session-level engagement for both youth and caregivers, after accounting for baseline engagement challenges, maximum practice extensiveness, site, and study condition. Variance decomposition of youth and caregiver session-level engagement also revealed that although the therapist level accounted for significant variance (23.0%) in youth session engagement, caregiver session engagement was more organized at the client level (22.3%). Together, these findings reinforce the conceptualization of engagement as a dynamic, state-like phenomenon that is co-constructed within the session rather than trait-like features of clients, and position therapist behaviors as an important component of session-to-session engagement. Overall, these studies found that therapist missteps occur routinely in youth publicly funded mental health settings and are associated with measurable changes in session-level engagement. Additionally, provision of coordinated clinical supports aimed at supporting therapists with navigating well-documented “blind curves” when delivering care in complex contexts, as well as extensive delivery of an evidence-based practice, were associated with expected decreases in misstep occurrences. These findings continue to support the theoretical framing of therapist missteps as predictable features of treatment delivery and center a locus of intervention that shifts away from the therapist’s intrinsic traits and qualities and towards scaffolding flexible, matched, and coordinated clinical decision-making supports to improve care for youth and families.