Journal of Consulting and Clinical Psychology, Vol 93(11), Nov 2025, 735-748; doi:10.1037/ccp0000972
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. Method: Data from six clinical trials of the modular approach to therapy for children with anxiety, depression, trauma, or conduct problems modular psychotherapy were combined (N = 490; 5,403 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). Multilevel 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 (Bs = −.369 to −.368; ps