Does emotional distress tolerance negatively predict problematic smartphone use or vice versa? Evidence from a longitudinal study and a daily diary study.

Low emotional distress tolerance (EDT) is a risk factor for problematic smartphone use (PSU). While theoretical and preliminary empirical considerations suggest that PSU may impair EDT, no studies have directly examined their bidirectional relationship. To address this gap, in this research, the bidirectional relationship between PSU and EDT is investigated through two studies among young adults. Study 1 employed a two-wave longitudinal design. A total of 901 young adults (61.7 % women) completed questionnaires three months apart. A cross-lagged regression analysis revealed a significant bidirectional predictive relationship between EDT and PSU. Study 2 used a daily diary design (N = 77; 39.0 % women) to examine the day-to-day directional relationship between EDT and PSU. Participants completed daily assessments over 14 consecutive days. Multilevel linear models with time lag analyses indicated that PSU predicted next-day EDT, whereas EDT did not predict next-day PSU. Study 1 revealed a reciprocal negative association between EDT and PSU, offering empirical support for Compensatory Internet Use Theory (CIUT) and the reinforcing cycle of the Interaction of Person-Affect-Cognition-Execution (I-PACE) model. Moreover, on a daily timescale, only PSU was found to predict next-day EDT. These findings have implications for interventions aiming to break the cycle between PSU and low EDT.