Background Owing to the widespread use of smartphones, researchers have an increasing interest in smartphone addiction. The purpose of this study is to look into the outcomes of smartphone addiction while answering when and how smartphone addiction may predict university students’ depression and anxiety. Methods Primary data were collected from 355 students studying in different universities in China. Participants completed Smartphone Addiction Scale-Short Version (SAS-SV), Bedtime Procrastination Scale (BPS), Self-control Scale (SCS) and Depression-Anxiety-Stress Scale (DASS). PROCESS macros in SPSS24.0 were used to examine the moderated mediating effects. Results Smartphone addiction Scale scores were positively correlated with depression, anxiety among university students through bedtime procrastination. Self-control was found to play the moderating role such that the mediated relationships were weak for students with high self-control. Limitations This study is a cross sectional study, so we cannot make causal inferences. Conclusions Individuals with smartphone addiction are inclined to postpone their bedtime and further experience more depression and anxiety. Self-control serves as a protective factor for bedtime procrastination, depression and anxiety.
