Technological devices play a central role in adolescents life. Despite concerns about negative effects of excessive screen time on mental health and development, there is little knowledge of fundamental features of screen behaviours and underlying genetic architecture. Using self reports from adolescents (14-16 years old) in the Norwegian Mother, Father, and Child Cohort Study (MoBa, n = 18 490), we performed genome-wide association analysis for four screen behaviors: time spent 1) watching movies/series/TV; 2) gaming; 3) sitting/lying down with PC, mobile or tablet; and 4) communicating with friends on social media. The resulting summary statistics were analysed using the conditional false discovery rate (condFDR) approach to increase genetic discovery. We also estimated SNP-based heritabilities of the screen behaviours and the genetic correlations with six major psychiatric disorders (schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorder, attention deficit hyperactivity disorder, alcohol use disorder), and educational attainment. The screen-based phenotypes displayed significant SNP-based heritabilities (0.048-0.12). We also observed significant genetic correlations between screen behaviours and psychiatric disorders (rg range: 0.21-0.42). Educational attainment demonstrated significant negative genetic correlation with screen behaviours, most strongly with social media use (rg = -0.69). CondFDR analysis identified three novel loci associated with social media use. Thus, we show that screen behaviors are heritable, polygenic traits that partly share genetic signal with mental disorders and educational attainment. Future studies and larger samples are required to clarify causal relationships between these traits and disorders, and to validate the identified genetic loci associated with social media use.

Professor Ole A. Andreassen has received speaker fees from Lundbeck, Janssen, Otsuka, and Sunovion, and is a consultant to Cortechs.ai, and Precision Health AS. Dr. Oleksandr Frei is a consultant to Precision Health AS. No potential conflict of interest was reported by other authors.

This work was supported by the Research Council of Norway (Grant No. 324499, 326813, 271555/F21, 274611, 324620), the South-Eastern Norway Regional Health Authority (Grant No. 2022073), the European Economic Area and Norway Grants (EEA-RO-NO-2018-0535, EEA-RO-NO-2018-0573), and the European Unions Horizon 2020 Research and Innovation Programme (Grant No. 847776, 964874).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The establishment of MoBa and initial data collection was based on a license from the Norwegian Data Protection Agency and approval from The Regional Committees for Medical and Health Research Ethics (REK). The MoBa cohort is currently regulated by the Norwegian Health Registry Act, and the current study was approved by REK (2016/1226/REK).

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The datasets supporting the conclusions of this article are available from the Norwegian Institute of Public Health, but restrictions apply to the availability of these data. The study website provides details on how to access data and information on the available variables (https://www.fhi.no/en/ch/studies/moba/for-forskere-artikler/research-and-data-access/).