 This study examined the relationship between WeChat usage and depression among middle-aged and elderly people in China. It found that WeChat usage was associated with lower levels of depression, and that social participation partially mediated this relationship. Recreational activities were found to have the strongest mediation effect, while the effects of voluntary activities, cultural activities, and other activities were not significant. This suggests that encouraging more active social participation and other types of social activities may help reduce depression among middle-aged and elderly people in China. This article was offered by Gailing Wang, Jing Duan, Chen Xiangkang, and others.