The purpose of this study was to investigate the underlying mechanism between social network sites addiction and depression in adolescents. Based on the Diathesis-stress theory,a questionnaire,including Social Network Sites Addiction Scale,Cognitive Overload Scale,Core Self-Evaluations Scale,and Center for Epidemiologic Studies Depression Scale( CES-D),was used to investigate 886 junior school students from three full-time middle schools in Wuhan. The results indicated that:( 1) There were significant correlations among social network site...