The impact of social isolation on smartphone addiction among college students: the multiple mediating effects of loneliness and COVID-19 anxiety

Background: The widespread use of smartphones has significantly increased smartphone addiction among college students, especially during the COVID-19 pandemic. Strict closed-campus management, social distancing, and prohibitions against gatherings in mainland China heightened loneliness and anxiety, increasing addiction risk. Although social isolation is a known predictor, the complex mechanisms linking social isolation and smartphone addiction in the COVID-19 context remain unclear. Objective: To jointly examine social isolation, loneliness, and COVID-19 anxiety and clarify mechanisms by building a multiple mediation model. Method: Quota proportional sampling across eight higher education institutions in Conghua District (Guangzhou) recruited students via WeChat groups (Dec 10–15, 2022). Of 900 questionnaires, 868 valid responses were retained (620 females, 248 males). Results: Social isolation had a significant direct effect on smartphone addiction. Loneliness and COVID-19 anxiety mediated the association in both parallel and sequential pathways. A reverse mediation model was also supported, with COVID-19 anxiety as the first mediator and loneliness as the second. Conclusion: Social isolation increases smartphone addiction risk among college students, primarily via subjective psychological states (loneliness, anxiety) triggered by campus isolation and social distancing. Interventions should target these psychological factors to reduce addiction.