Understanding the Role of Therapist Quality in Accounting for Heterogeneity of Patient Outcomes in Psychosocial Chronic Pain Treatments

A variety of evidence-based psychosocial treatments now exist for chronic pain. However, on average, effect sizes have tended to be modest and there is a high degree of heterogeneity in treatment response. In this focus article, we explore the potential role that therapist quality in delivering treatment may have in accounting for a degree of this variability in outcome. Therapist quality refers to the skillful delivery of treatment, harnessing both specific and common therapeutic factors during sessions. While recognized as important to assess and report in clinical trials by some reporting guidelines, few randomized controlled trials evaluating psychosocial treatments for chronic pain have reported on therapist factors. We reviewed the clinical trials included in three systematic reviews and meta-analyses of trials of cognitive-behavioral therapy (mainly), mindfulness-based interventions, and acceptance and commitment therapy. We found that of the 134 trials included, only nine assessed and reported therapist quality indicators, with a variety of procedures used. This is concerning as without knowledge of the quality in which treatments are delivered, the estimates of effect sizes reported may be misrepresented. We contextualize this finding by drawing on the broader psychotherapy literature which has shown that more skillful, effective therapists demonstrated ten times better patient response rates. Examination of the characteristics associated with these more effective therapists tends to indicate that skillful engagement of common factors in therapy sessions represents a distinguishing feature. We conclude by providing recommendations for assessing and reporting on therapist quality within clinical trials evaluating psychosocial treatments for chronic pain. PERSPECTIVE: Therapist quality in the delivery of psychosocial treatments for chronic pain has rarely been assessed in clinical trials. We propose that therapist quality indicators are an under-studied mechanism that potentially contributes to the heterogeneity of treatment outcomes. We provide recommendations for assessing and reporting on therapist quality in future trials.

Initial development and psychometric properties of the Therapist Quality Scale

PURPOSE/OBJECTIVE

This study sought to develop and evaluate the psychometric properties of a brief measure of the quality of therapist treatment delivery that would be applicable for use across different types of psychosocial chronic pain treatments: the Therapist Quality Scale (TQS).

RESEARCH METHOD/DESIGN

An initial pool of 14 items was adapted from existing measures, with items selected that are relevant across interventions tested in a parent trial comparing an 8-week, group, Zoom-delivered mindfulness meditation, cognitive therapy, and behavioral activation for chronic back pain from which data for this study were obtained. A random selection of 25% of video-recorded sessions from each cohort was coded for therapist quality (two randomly selected sessions per group), with 66 sessions included in the final analyses (n = 33 completed pairs). Items were coded on a 7-point Likert-type scale. Exploratory factor analysis (EFA) and reliability estimates were generated.

RESULTS

EFA showed a single-factor solution that provided a parsimonious explanation of the correlational structure for both sessions. Eight items with factor loadings of ≥ .60 in both sessions were selected to form the TQS. Reliability analyses demonstrated all items contributed to scale reliability, and internal consistency reliabilities were good (αs ≥ .86). Scores for the eight-item TQS from the two sessions were significantly correlated (r = .59, p < .001).

CONCLUSIONS/IMPLICATIONS

The TQS provides a brief measure with preliminary psychometric support that is applicable for use across different types of treatments to rate the quality of the therapist's delivery. The items assess quality in delivering specific techniques, maintaining session structure, and in developing and maintaining therapeutic rapport. (PsycInfo Database Record (c) 2024 APA, all rights reserved).