A 2025 longitudinal study challenges the idea that greater discipline automatically creates happiness: across American and Asian samples, improvements in psychological well-being predicted stronger self-control months later, while greater self-control did not predict later well-being—suggesting that feeling better may make discipline easier, rather than discipline always making us feel better.

Two three-wave samples found that earlier well-being predicted later self-control, while self-control did not reliably forecast later well-being after stable personal differences were separated.