Too little, too much: a 4-year longitudinal study of within-person deviations in propensity for overinvolvement and student well-being.

University students face mounting pressure to seize every opportunity, yet the long-term costs of this tendency remain poorly understood. This 4-year longitudinal study examined how the propensity for overinvolvement relates to sleep quality and well-being, and whether resilience buffers its effects. A sample of 370 university students (55% White, 68% female) completed annual Fall assessments of propensity for overinvolvement, resilience, sleep quality, and psychological well-being at orientation and across their four undergraduate years. Using a random intercept cross-lagged panel model with latent interactions, our preregistered analyses yielded no evidence of linear effects: propensity for overinvolvement was not associated with poorer sleep or well-being, nor did resilience moderate these relations. In contrast, exploratory analyses of nonlinear within-person effects revealed a consistent pattern: when students deviated from their own typical level of overinvolvement-becoming either more or less overinvolved than usual-they reported poorer sleep quality and lower well-being, and lower resilience, at the subsequent time point. Because these nonlinear effects were exploratory and the preregistered linear and moderation hypotheses were not supported, we interpret them as hypothesis-generating and in need of replication. Consistent with prior work on overinvolvement, these findings suggest that helping students recognize and maintain a stable, personally sustainable level of engagement, rather than continually maximizing involvement, may be a useful focus for student self-monitoring, academic advising, and campus counseling services.