Emotion regulation as a mechanism of change in transdiagnostic low-intensity cognitive behavioral therapy for internalizing distress: Disaggregating within vs. between individual

Objective: In recent years, emotion regulation strategies such as cognitive reappraisal (CR) and expressive suppression (ES) have emerged as potential transdiagnostic mechanisms of change. Functional models of emotion dysregulation hypothesize that avoidance strategies like ES maintain internalizing distress symptoms, but these models have not received close empirical scrutiny in treatment studies. The objective of this study was to test whether week-to-week within-person changes in CR and ES predicted changes in negative affect (NA) and positive affect (PA) in a guided self-help intervention. Methods: N = 141 participants were recruited for a six-week remote trial of a guided self-help transdiagnostic CBT (NCT04870099). NA was measured with the Kessler Scale Psychological Distress Scale (K6) and PA with the World Health Organization-5 Well-being Index (WHO-5). We used the Emotion Regulation Questionnaire (ERQ) to measure CR and ES and disaggregated within- versus between-person variability using a random intercept cross-lagged panel model. Results: Participants (Mage = 40.36, SDage = 13.95, nfemale = 120, nnon-Hispanic white = 110) improved in NA, PA, CR, and ES across the trial, with the smallest improvements in ES. At the between-person level, CR was associated with both NA (r = -0.22, p = .022) and PA (r = 0.40, p < .001). At the within-person level, week-to-week changes in CR were associated with subsequent week-to-week decreases in NA (ranging from β = -0.28 to β = -0.55). Conclusions: Our findings support the role of cognitive restructuring as a mechanism of change in transdiagnostic CBT.