Changes in smartphone dependence and depressive and anxiety symptoms among Chinese adolescents

Previous studies have examined the associations of baseline smartphone dependence (SPD) with depressive symptoms and anxiety symptoms, ignoring changes in SPD over time. Especially, it is unclear whether individuals quitting SPD remain at high risk for depressive symptoms and anxiety symptoms. This study aimed to investigate the longitudinal associations of changes in SPD with depressive symptoms and anxiety symptoms among adolescents.

From September to December 2021 (wave 1), we recruited adolescents in grades 4 and 7 in five public primary schools and nine public junior high schools in Shenzhen, China, and collected information on SPD using the Smartphone Addiction Scale-Short Version. The cut-off values of ≥ 31 and ≥ 33 were used in boys and girls, respectively, to identify adolescents with SPD. From September to December 2022 (wave 2), in addition to SPD, we collected the information on depressive symptoms and anxiety symptoms using the 9-item version of Patient Health Questionnaire and the 7-item version of General Anxiety Disorder Scale, respectively. The cut-off values for clinically significant symptoms were both ≥ 10. Four patterns of changes in SPD during waves 1-2 were defined: none, quitting, new-onset, and persistent. From September to December 2023 (wave 3), we assessed depressive symptoms and anxiety symptoms again.

Of the 3088 adolescents included, the mean age was 12.5 (standard deviation [SD], 1.4) years and 54.3% were boys. Compared with adolescents without SPD, those with new-onset SPD (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.06 to 2.31) or persistent SPD (OR, 2.37; 95% CI, 1.56 to 3.61) showed a higher risk of depressive symptoms, but those quitting SPD did not (OR, 1.33; 95% CI, 0.83 to 2.12). We have observed a similar association between changes in SPD and anxiety symptoms. Several sensitivity analyses confirmed the robustness of the results.

Our findings suggest that adolescents with SPD might be a high-risk group for depressive symptoms and anxiety symptoms, and quitting SPD might help prevent them from developing depressive symptoms and anxiety symptoms.