Time-varying mediation effects of health warning labels on smoking cessation-related cognition and behavior: Evidence from a randomized trial using ecological momentary assessment.

INTRODUCTION: Health warning labels (HWLs) on cigarette packs influence risk perceptions and cessation behaviors, but their effects diminish over time. Time-varying mediation modeling can uncover when and how HWLs affect cessation-related cognitions and behaviors. METHODS: As part of a two-week randomized trial, US adult daily smokers (N = 179) received cigarette packs with either control HWLs or HWLs plus inserts containing rotating efficacy messages about quitting benefits and cessation tips. Using time-varying mediation models with ecological momentary assessment data, we examined how inserts (vs control) influenced daily cognitive elaboration of cessation benefits and subsequent forgoing of cigarettes (i.e., next day) and whether those effects changed over time. RESULTS: Over two weeks, inserts progressively increased cognitive elaboration, reaching statistical significance around day 6. The association between cognitive elaboration and forgoing a cigarette the next day was significant across the study period, peaking mid-study. Direct effects of inserts on forgoing behavior emerged in the first week and stabilized after day 7. The indirect (mediated) effect of inserts on forgoing via cognitive elaboration increased during the first week and declined slightly in the second week. CONCLUSIONS: Inserts gradually increased both cognitive elaboration of quitting benefits and forgoing cigarettes, with mediation of insert effects by cognitive elaboration peaking after one week, then declining. These findings suggest that additional communication strategies, perhaps using different channels, may be necessary to boost HWL effects on cessation-related behaviors that are mediated through the pathway of cognitive elaboration of cessation benefits.