From self-regulation to character: Digital well-being intervention effects on character strengths and subsequent distress.

Character strengths (CS) are theorized to be a core mechanism of human flourishing, yet causal evidence for their malleability and role in mental health remains limited. In a randomized controlled trial of a 13-week digital well-being intervention among 2,315 healthcare professionals in Mexico, we showed that the intervention increased a general CS factor relative to a waitlist control (β = 0.515, p < .001). Increases in CS mediated reductions in psychological distress at 37-week follow-up (indirect effect = -0.013, p = .032), accounting for 4.9% of the total effect. This mediation remained significant after controlling for social connection and insight into emotional processes, indicating that CS represent a distinct mechanism of change. CS did not mediate improvements in well-being, suggesting they primarily function as a resilience factor buffering distress. This study advances a causal science of character and identifies CS as a tractable target for intervention in high-stress occupational settings.