Nonlinear Association Between Age and Social Media Use with the Interaction of Anxiety and Depression: A National Cross-Sectional Study Among15–34-year-old Chinese Youth
1
The Affiliated Brain Hospital, Guangzhou Medical University, Guangzhou, China
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
BACKGROUND:
Social media (SM) use among youth is influenced by both age and mental health factors such as anxiety and depression. However, previous studies mostly relied on linear assumptions. This study aims to examine the nonlinear effects of age on daily SM use time, quantify changes across different age groups, and validate the interaction with anxiety/depression .
METHODS:
A total of 2011 active SM users aged 15-34 from 30 provinces were recruited from major Chinese platforms (Douyin, Rednote, etc.) between June and August 2025. Data on demographics, SM use characteristics and mental health status (anxiety, depression, sleep quality, social support, stress coping) were collected. The generalized additive model (GAM) was applied to examine the nonlinear effect of age and its interaction with anxiety and depression. General linear models was used to estimate changes in daily SM use across age.
RESULTS:
Participants (mean age of 23.7±4.1 years ,42.3% female) reported 3.12±2.82 hours of daily SM. Short-video platforms were most frequently used (69.7%), and spent 11.8% more time daily on SM, and 10.7% with SM addiction spent 20.5% more time.Age showed a significant nonlinear association with daily SM use time (P<0.001). Each additional year increased use by 10.3% below 18 (P=0.002) and decreased by 2.5% above 25 (P=0.004). The significant interaction effect between depression and age (P=0.009) showed positive for those aged <20.7, with the most SM use among 18-year-olds with severe depression. The effect turned negative for those above 20.7, while people aged ≥29.0 with severe depression had significantly longer daily SM use. No significant interaction was found with anxiety.
CONCLUSIONS:
Daily SM use rises with age among minors but declines after 25, except among those with severe depression over 29. Age- and mental health–specific interventions are needed to promote balanced SM engagement and prevent excessive or addictive use among youths.
Social media (SM) use among youth is influenced by both age and mental health factors such as anxiety and depression. However, previous studies mostly relied on linear assumptions. This study aims to examine the nonlinear effects of age on daily SM use time, quantify changes across different age groups, and validate the interaction with anxiety/depression .
METHODS:
A total of 2011 active SM users aged 15-34 from 30 provinces were recruited from major Chinese platforms (Douyin, Rednote, etc.) between June and August 2025. Data on demographics, SM use characteristics and mental health status (anxiety, depression, sleep quality, social support, stress coping) were collected. The generalized additive model (GAM) was applied to examine the nonlinear effect of age and its interaction with anxiety and depression. General linear models was used to estimate changes in daily SM use across age.
RESULTS:
Participants (mean age of 23.7±4.1 years ,42.3% female) reported 3.12±2.82 hours of daily SM. Short-video platforms were most frequently used (69.7%), and spent 11.8% more time daily on SM, and 10.7% with SM addiction spent 20.5% more time.Age showed a significant nonlinear association with daily SM use time (P<0.001). Each additional year increased use by 10.3% below 18 (P=0.002) and decreased by 2.5% above 25 (P=0.004). The significant interaction effect between depression and age (P=0.009) showed positive for those aged <20.7, with the most SM use among 18-year-olds with severe depression. The effect turned negative for those above 20.7, while people aged ≥29.0 with severe depression had significantly longer daily SM use. No significant interaction was found with anxiety.
CONCLUSIONS:
Daily SM use rises with age among minors but declines after 25, except among those with severe depression over 29. Age- and mental health–specific interventions are needed to promote balanced SM engagement and prevent excessive or addictive use among youths.
| eISSN: | 2654-1459 |
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