Adolescents average 50 minutes of smartphone use during school nights

A cross-sectional study of US adolescents found that smartphone use during school nights was common, with social media accounting for most nighttime activity, and more than half of participants using devices during overnight hours.

The study, published in JAMA Pediatrics, analyzed smartphone app use data from 657 adolescents enrolled in the Adolescent Brain Cognitive Development (ABCD) Study. Investigators used passive sensing data collected through the Effortless Assessment Research System (EARS) mobile app, which logs foreground app activity on Android smartphones.¹

Researchers evaluated smartphone use during school nights, defined as Sunday through Thursday between 10 PM and 6 AM. The analytic sample had a mean age of 15.3 years, and participants represented diverse racial, ethnic, and socioeconomic backgrounds.

Overall, adolescents spent a mean of 50.1 minutes using smartphones during school nights. Social media apps, including YouTube, Instagram, and TikTok, accounted for the largest share of use, with participants averaging 32.7 minutes nightly on these platforms. Entertainment apps such as Netflix and Disney+ averaged 8.5 minutes of use, followed by gaming apps at 7.6 minutes.

Investigators reported that “adolescents used a smartphone for an average of 50 minutes during school nights, with more than 65% of that spent on social media apps.”

Which apps were used most during school nights?

The findings also showed that nighttime smartphone use frequently extended into overnight hours. A total of 342 adolescents, representing 52.1% of the sample, used their smartphones between midnight and 4 AM at least once during the study period. Among these adolescents, the mean overnight use was 23.7 minutes.

The authors noted that “roughly half of the adolescents using smartphones during the shorter middle-of-the-night assessment window (12:00 AM to 4:00 AM) indicates a possible disruption to their sleep on school nights or symptoms of sleep problems.”

Researchers also identified sociodemographic differences in nighttime smartphone use. In adjusted analyses, Black adolescents had significantly higher total smartphone and social media use during school nights compared with White adolescents. Lower household income was also associated with greater nighttime smartphone use. Female participants, however, had lower social media use than male participants during school-night hours.

What are the sleep implications of nighttime smartphone use?

The study builds on prior research suggesting that screen use near bedtime may delay or disrupt sleep. The authors referenced evidence showing that even modest increases in sleep duration may improve cognitive and mental health outcomes in adolescents. According to the investigators, “Prior studies have shown that incremental extensions in sleep, as low as 10 to 15 minutes, are associated with better cognitive and mental health outcomes, suggesting that these findings have significant public health implications.”²

The authors said the findings complement previous ABCD-EARS research demonstrating that social media is among the most commonly used app categories during school hours as well. They added that disparities in nighttime screen use could contribute to observed differences in adolescent sleep duration and bedtime patterns across demographic groups.

Study limitations included the cross-sectional design, inability to establish causality, reliance on Android smartphone users, and lack of direct sleep assessment. Still, the investigators said the study provides objective data on adolescent smartphone behavior during hours typically reserved for sleep.

“To fully understand the risks of nighttime smartphone usage, future smartphone research should link smartphone usage (ie, timing of usage or app types) to adolescent sleep, well-being, and academic outcomes,” the authors concluded.

Reference

1. Nagata JM, Kim KE, Leong AW, et al. Smartphone use on school nights in the Adolescent Brain Cognitive Development Study. JAMA Pediatr. Published online May 18, 2026. doi:10.1001/jamapediatrics.2026.1707
2. Nagata JM, Kim KE, Huang OH, et al. Smartphone use during school hours by US youth in the Adolescent Brain Cognitive Development Study. JAMA. 2026;335(5):453-456. doi:10.1001/jama.2025.23235