Mediated effects of insomnia in the association between problematic social media use and subjective well-being among university students during COVID-19 pandemic

•Problematic social media use was positively and significantly associated with insomnia and negatively and significantly associated with well-being.•Insomnia was negatively and significantly associated with well-being.•Indirect effects of problematic social media use on subjective well-being (overall and its subscales) via insomnia were significant.•The direct effect of problematic social media use on subjective well-being (overall and its subscales) was insignificant in the presence of insomnia.•Clinicians need to assess sleep quality for people who have problematic use of the internet and social media and accurately treat it.