Perceived self-control mediates momentary mindfulness and affective states in daily life: A dynamic structural equation modeling approach

Momentary positive affect (PA) and negative affect (NA) are dynamic, modifiable indicators of mental health in daily life that are associated with psychological well-being and psychopathology. Although mindfulness is consistently associated with better affective well-being, the momentary mechanisms linking state mindfulness to affect remain unclear. This study tested whether momentary perceived self-control mediates this association in college students’ daily life at the within-person level. Undergraduate students (N = 282) completed up to six ecological momentary assessments (EMA) per day for seven days (7,622 observations). Momentary mindfulness, perceived self-control, PA, and NA were assessed at each prompt. Two contemporaneous 1-1-1 dynamic structural equation models tested within-person mediation in Mplus 8.9, separately for PA and NA. Models adjusted for first-order autoregressive effects and relevant temporal and person-level covariates. Moments of higher-than-usual mindfulness were associated with higher-than-usual perceived self-control, which in turn was associated with higher PA and lower NA. The 95% credible intervals for the within-person indirect effects excluded zero for both outcomes (PA: ab = 0.077, 95% credible interval (CrI) [0.062, 0.091]; NA: ab = − 0.080, 95% CrI [− 0.096, − 0.064]), as did those for the direct effects, indicating partial mediation. Notably, perceived self-control accounted for a larger proportion of the mindfulness–NA association than the mindfulness–PA association, 46.0% versus 25.4%. Findings suggest that momentary perceived self-control could be a promising tailoring variable for just-in-time adaptive interventions delivering brief mindfulness-based micro-prompts for affect regulation, particularly for managing NA, in college students’ daily life.