Grit, as an important positive psychological quality, has rarely been studied for its role involved in the mechanism between stress and psychological security. This article explores the moderating and mediating role of grit in the relationship between interpersonal stress and psychological security of freshmen through two studies. In study 1, freshmen from several Chinese universities (N = 1,224) were recruited to complete a battery of questionnaire, including assessments about interpersonal stress, grit, and psychological security. The moderating effect analysis showed that grit moderated the relationship between interpersonal stress and psychological security. Specifically, grit buffered the negative effects of interpersonal stress on freshmen’s psychological security, but this effect was obvious only when the level of interpersonal stress was relatively low, and decreased when the level of interpersonal stress was high. In study 2, college freshmen from another university apart from above ones (N = 604) were recruited, and we verified the results of study 1 and further explored the mediating role of grit in the relationship between interpersonal stress and security. The moderating effect analysis of study 2 also verified that of study 1. The mediating effect analysis showed that interpersonal stress not only negatively predicted psychological security, but also affected psychological security through the mediation of grit. In general, grit played a mediating and moderating role in the relationship between interpersonal stress and psychological security. This study provides first-hand evidence to explain the multiple roles of grit in the relationship between interpersonal stress and psychological security.

Although excessive smartphone use has been confirmed as being associated with specific representations of mental health (e. g., anxiety, depression, wellbeing, etc.) throughout the COVID-19 pandemic, the relationship between excessive smartphone use and cognitive representations of mental health (i.e., psychological safety) is not yet fully understood. This study aimed to identify the association between excessive smartphone use and psychological safety among university freshmen during the COVID-19 pandemic; in addition, we examined the mediation effects of hardiness and interpersonal distress in this relationship. In this study, 1,224 university freshmen were selected at random from several universities in Guizhou Province of China. The Psychological Safety Scale was used to evaluate the mental health of university freshmen; the Mobile Phone Dependence Scale was used to evaluate excessive smartphone use; the Hardiness Questionnaire was used to evaluate hardiness; and the Interpersonal Relation Synthetic Diagnose Test was used to evaluate interpersonal distress. The findings showed that: (1) the greater the degree of excessive smartphone use, the more serious respondents' interpersonal distress and the lower their hardiness; (2) excessive smartphone use was not only directly related to the psychological safety of university freshmen but also indirectly related to their psychological safety through the independent mediation of hardiness and interpersonal distress, as well as through the chain mediation of hardiness and interpersonal distress. In general, excessive smartphone use in university freshmen could lead to a decline in their psychological safety. Also, hardiness and interpersonal distress play a complex role in this relationship. During the COVID-19 pandemic, interventions on the mental health of college freshmen should not only provide guidance on how to use their smartphone responsibly but also to provide them with support and guidance for the enhancement of their hardiness and improvement of their interpersonal relationships.