This study aimed to examine the impact of online social support on mental health during the COVID-19 pandemic and to investigate the mediating role of problematic social media use and the moderating role of social isolation experiences. We collected data from 461 online questionnaires nationwide and built structural models of depression, anxiety, and sleep using structural equation modeling. Results showed that online companionship support had an indirect negative effect on depression, anxiety, and sleep through problematic social media use. Notably, this effect was significant only when indiv...
