Between- and within-person relations between treatment modules and symptom improvements across six randomized controlled trials

Objective: Most youth psychotherapies contain multiple treatment elements; little is known about their relative effectiveness. We assessed symptom improvements associated with treatment elements, represented by modules within modular psychotherapy.Methods: Data from six clinical trials of the MATCH modular psychotherapy were combined (N=490; 5403 sessions; 6-15 years) to test effects of modules grouped into seven common treatment principles: Feeling Calm (e.g., relaxation strategies), Increasing Motivation (e.g., contingency management), Repairing Thoughts (e.g., cognitive restructuring), Solving Problems (e.g., problem solving), Trying the Opposite (e.g., exposure), Engagement/Psychoeducation (e.g., building rapport), and Future Planning (e.g., planning skill use). Multi-level models with autoregressive covariance controlled for previous symptoms, session number, and baseline symptoms; accounted for temporality with each session occurring prior to associated outcomes; importantly, we modeled associations between outcomes and between- and within-person use of treatment principles. Measures included weekly youth- and caregiver-reported internalizing, externalizing, and total symptoms, plus idiographic top problems.Results: A between-person effect linked Future Planning (B’s=-.369 — -.368; p’s<.05) to better outcomes. Better within-person effects were observed for Increasing Motivation (B’s=-0.087 — -0.057; p's<.05), Trying the Opposite (B’s=-.087 – -.056); p’s<.05), and Future Planning (B=-0.146; p<.001). Six outcomes showed worse within-person effects for Engagement/Psychoeducation (B’s=.036 — .099; p’s<.05); efforts to build engagement drove this finding; those efforts were associated with less use of skills-focused principles.Conclusions: Increasing Motivation, Trying the Opposite, and Future Planning were associated with especially good outcomes; therapists’ engagement attempts were associated with less focus on skill-building, and poorer immediate outcomes. Results may inform youth psychotherapy decision-making research and practice.