Objective:

To examine the association between time spent online, cognitive performance, and depressive symptoms in Chinese adolescents.

Approach:

• Data Analysis: Analyzed data from the 2018 wave of the China Family Panel Studies for 3,226 adolescents (aged 10–19 years) using linear regression models.
• Subgroup Analysis: Conducted subgroup and sensitivity analyses to check the robustness of the results.

Key Findings:

• Approximately 14.5% of Chinese adolescents had depressive symptoms.
• Increased mobile internet use was associated with better vocabulary performance (β = 0.31; 95% CI = 0.1, 0.52).
• No significant association was found between mobile internet use and mathematics performance.
• Adolescents with depressive symptoms had significantly lower vocabulary performance (β = −1.49; 95% CI = −2.03, −0.95) and mathematics performance (β = −1.16; 95% CI = −1.58, −0.74).
• A significant interaction between mobile internet use and depressive symptoms was observed for vocabulary performance (β = 0.41; 95% CI = 0.17, 0.65).

Interpretation:

Depressive symptoms were associated with lower cognitive performance in vocabulary and mathematics, while mobile internet use showed a positive association with vocabulary performance.

Limitations:

• The study is cross-sectional, limiting causal inferences.
• Potential unmeasured confounding factors such as home environment or baseline mental health may affect results.

Conclusion:

The findings indicate a relationship between mobile internet use, depressive symptoms, and cognitive performance in Chinese adolescents, warranting further investigation.