Short-form video apps, such as TikTok, have become popular worldwide. Compared to traditional social media, they have powerful push algorithms and are more entertaining, which might lead to some negative effects. Research has attempted to identify the relationship between short-form video use and depression, but the processes mechanism underly the relationship was few in number. The present study explored the association between short-form video use and depression among Chinese adolescents and analyzed the mediating roles of need gratification and short-form video addiction. The participants included 1302 senior high school students (M_age = 16.03, SD = 0.76, 42.6 % boys). And a structure equation model with chain mediating was established using Mplus. The results showed (1) a direct association between short-form video use and adolescent depression, (2) that entertainment need gratification, social-related need gratification, and short-form video addiction acted as chain mediating factors, and (3) no gender difference in the model. The present study's findings revealed the important mediating role of addictive behavior between normal use behavior and depression and suggested that preventative and interventional plans based on need gratification should be developed to reduce short-form video addiction and improve mental health.

Family income is an important factor that affects depression in children and can indirectly be associated with children’s development through family and individual factors. However, few studies have examined the mechanism of multiple risk factors. Therefore, this study focused on the relationship between family income and child depression, as well as the chain mediating the roles of parental involvement and children’s self-esteem both in single-parent families and intact families. A total of 1355 primary school students completed questionnaires that assessed family income, parental involvement, children’s self-esteem, and depression. The results showed that family income influenced child depression through both the mediating roles of parental involvement and children’s self-esteem and the chain mediating role of parental involvement and children’s self-esteem. Meanwhile, family income only influenced child depression through chain mediation in single-parent families. The group differences in the mechanism of depression provide a reference for empirical research on depression intervention in children from different family structures.