The impact of loneliness on depression during the COVID-19 pandemic in China: a two-wave follow-up study

During the COVID-19 pandemic, many regions and countries implemented lockdowns and isolation to curb the virus's spread, which might increase loneliness and lead to a series of psychological distress. This study aims to investigate the association between loneliness and depression during the COVID-19 pandemic and examine whether perceived social support and perceived internal control mediate the loneliness-depression relationship in China. Self-report questionnaires were distributed online in two waves during the pandemic in 2020. At Wave 1, demographics and loneliness were reported when the lockdown was initially implemented in China, and at Wave 2, as the pandemic came under control and the epicenter lifted its lockdown. Depression, perceived social support, and perceived internal control were measured at both two waves. Higher levels of loneliness at Wave 1 were associated with more depression at Wave 2 after controlling for baseline depression and demographic variables. Simple mediation models showed that both perceived social support and internal control at two waves independently mediated the relationship between Wave 1 loneliness and Wave 2 depression. Additionally, the serial multiple mediation model indicated that perceived social support and perceived internal control sequentially mediated the path from loneliness to subsequent depression. A higher level of loneliness during the initial lockdown was linked with more severe depression with the development of the COVID-19 pandemic. Both perceived social support and perceived internal control acted as essential protective factors against depression from loneliness. Meanwhile, social support might protect mental health by enhancing the sense of self-control when facing loneliness.