Treatment as a moderator and executive function as a mediator of the effect of a mindfulness ecological momentary intervention for generalized anxiety disorder

Background Theory and research indicated that executive functioning (EF) correlated with, preceded, and stemmed from worry in generalized anxiety disorder (GAD). The present secondary analysis (Zainal & Newman, 2023b) thus determined whether EF domains mediated the effect of a 14-day (5 prompts/day) mindfulness ecological momentary intervention (MEMI) against a self-monitoring control (SM) for GAD. Method Participants (N = 110) diagnosed with GAD completed self-reported (Attentional Control Scale, GAD Questionnaire, Perseverative Cognitions Questionnaire) and performance-based tests (Letter-Number Sequencing, Stroop, Trail Making Test-B, Verbal Fluency) at baseline, post-treatment, and one-month follow-up (1MFU). Causal mediation analyses determined if pre-post changes in EF domains preceded and mediated the effect of MEMI against SM on pre-1MFU changes in GAD severity and trait repetitive negative thinking (RNT). Results MEMI was more efficacious than SM in improving pre-post inhibition (β = -2.075, 95% [-3.388, -0.762], p =.002), working memory (β = 0.512, 95% [0.012, 1.011], p =.045), and set-shifting (β = -2.916, 95% [-5.142, -0.691], p =.010) but not verbal fluency and attentional control. Within groups, MEMI but not SM produced improvements in all examined pre-post EF outcomes except attentional control. Only pre-post improvements in inhibition mediated the effect of MEMI against SM on pre-1MFU reductions in GAD severity (β = -0.605, 95% [-1.357, -0.044], p =.030; proportion mediated = 7.1%) and trait RNT (β = -0.024, 95% [-0.054, -0.001], p =.040; proportion mediated = 7.4%). These patterns remained after conducting sensitivity analyses with non-linear mediator-outcome relations. Conclusions Optimizing MEMI for GAD might entail specifically boosting inhibition plausibly by augmenting it with dialectical behavioral therapy, encouraging high-intensity physical exercises, and targeting negative emotional contrast avoidance.