Exploring genetic confounding of the associations between screen time and depressive symptoms in adolescence and early adulthood

Jiayao Xu; Jessie Baldwin; Amanda M. Hughes; Annie Herbert; Hannah J. Jones; Marcus R. Munafo; Laura D. Howe

doi:10.1093/ije/dyag079

Exploring genetic confounding of the associations between screen time and depressive symptoms in adolescence and early adulthood

Jiayao Xu
, Jessie Baldwin
, Amanda M. Hughes
, Annie Herbert
, Hannah J. Jones
, Marcus R. Munafo
, Laura D. Howe

University of Bristol
University College London
King's College London
NIHR Bristol Biomedical Research Centre

Research output: Contribution to journal › Article › peer-review

Abstract

Background: Digital devices have become a major aspect of children’s lives. Associations between screen time and mental health have been observed, but the causality remains unclear. This study aimed to investigate the associations between screen time and later depressive symptoms, and to test the robustness of these associations when accounting for genetic confounding. Methods: This study used data from the Avon Longitudinal Study of Parents and Children—a prospective cohort of children born between 1991 and 1992 in the UK. Different forms of screen time and depressive symptoms at ages 16, 22, and 26 years were assessed through self-completion questionnaires. The average daily screen time was calculated. Depressive symptoms were measured by using the Short Mood and Feelings Questionnaire (SMFQ). Polygenic scores (PGSs) for depression were calculated. Linear regression models were used to examine the associations between standardized screen time at ages 16, 22, and 26 years, and standardized depressive symptoms at age 26 years, adjusting for sociodemographic confounders and PGSs. Genetic sensitivity analysis (Gsens) was used to test for genetic confounding in these associations. Results: A total of 3003 participants were included in the analysis. Some, but not all, forms of screen time were associated with higher SMFQ scores, e.g. time spent using a phone, tablet, or e-book at age 22 years [β: 0.10, 95% confidence interval (CI) 0.07, 0.14 for weekdays; β: 0.08, 95% CI 0.04, 0.11 for weekends] and television time at age 26 years (β: 0.10, 95% CI 0.06, 0.14 for weekdays; β: 0.09, 95% CI 0.06, 0.13 for weekends). These associations persisted after adjustment for sociodemographic confounders and PGSs, but were attenuated in the Gsens (β = 0.03, 95% CI −0.01, 0.07 for the association with time spent using a phone, tablet, or e-book at age 22 years on weekends; β = 0.06, 95% CI 0.01, 0.10 for television time at age 26 years on weekends). Conclusion: For some measures of screen time, there were no associations with depressive symptoms. Where associations were seen, they were attenuated in the Gsens, implying that genetic confounding is present in the relationship between screen time and depressive symptoms in adolescents and young adults.

Original language	English
Article number	dyag079
Number of pages	10
Journal	International Journal of Epidemiology
Volume	55
Issue number	3
Early online date	11 Jun 2026
DOIs	https://doi.org/10.1093/ije/dyag079
Publication status	Published - 11 Jun 2026

Data Availability Statement

The informed consent obtained from ALSPAC participants does not allow the data to be made available through any thirdparty-maintained public repository. Supporting data are available from ALSPAC upon request under the approved proposal number B4380. Full instructions for applying for data access can be found at http://www.bristol.ac.uk/alspac/researchers/ac cess/. The ALSPAC study website contains details of all available data (http://www.bristol.ac.uk/alspac/researchers/our-data/).

Acknowledgements

We are extremely grateful to all the families who took part in this study, the midwives for their help in recruiting them, and the whole ALSPAC team, which includes data-collection staff, data and administration staff, technical managers, and the technical staff with the Bristol Bioresource Laboratory, based within the University of Bristol.

Funding

The UK Medical Research Council and Wellcome (grant ref: MR/Z505924/1) and the University of Bristol provide core support for ALSPAC. Genome-wide genotyping data were generated by Sample Logistics and Genotyping Facilities at Wellcome Sanger Institute and LabCorp (Laboratory Corporation of America) using support from 23andMe. This publication is the work of the authors and they will serve as guarantors for the contents of this paper. This study was supported by the Medical Research Council Integrative Epidemiology Unit (MC_UU_00032/7). A.H. was supported by the Wellcome Trust (grant ref: 224114/Z/21/Z).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

ALSPAC
depression
genetic confounding
screen time

ASJC Scopus subject areas

Epidemiology

Access to Document

10.1093/ije/dyag079Licence: CC BY

Cite this

@article{dd1777851ca740fcba0b650a4489dfc3,

title = "Exploring genetic confounding of the associations between screen time and depressive symptoms in adolescence and early adulthood",

abstract = "Background: Digital devices have become a major aspect of children{\textquoteright}s lives. Associations between screen time and mental health have been observed, but the causality remains unclear. This study aimed to investigate the associations between screen time and later depressive symptoms, and to test the robustness of these associations when accounting for genetic confounding. Methods: This study used data from the Avon Longitudinal Study of Parents and Children—a prospective cohort of children born between 1991 and 1992 in the UK. Different forms of screen time and depressive symptoms at ages 16, 22, and 26 years were assessed through self-completion questionnaires. The average daily screen time was calculated. Depressive symptoms were measured by using the Short Mood and Feelings Questionnaire (SMFQ). Polygenic scores (PGSs) for depression were calculated. Linear regression models were used to examine the associations between standardized screen time at ages 16, 22, and 26 years, and standardized depressive symptoms at age 26 years, adjusting for sociodemographic confounders and PGSs. Genetic sensitivity analysis (Gsens) was used to test for genetic confounding in these associations. Results: A total of 3003 participants were included in the analysis. Some, but not all, forms of screen time were associated with higher SMFQ scores, e.g. time spent using a phone, tablet, or e-book at age 22 years [β: 0.10, 95\% confidence interval (CI) 0.07, 0.14 for weekdays; β: 0.08, 95\% CI 0.04, 0.11 for weekends] and television time at age 26 years (β: 0.10, 95\% CI 0.06, 0.14 for weekdays; β: 0.09, 95\% CI 0.06, 0.13 for weekends). These associations persisted after adjustment for sociodemographic confounders and PGSs, but were attenuated in the Gsens (β = 0.03, 95\% CI −0.01, 0.07 for the association with time spent using a phone, tablet, or e-book at age 22 years on weekends; β = 0.06, 95\% CI 0.01, 0.10 for television time at age 26 years on weekends). Conclusion: For some measures of screen time, there were no associations with depressive symptoms. Where associations were seen, they were attenuated in the Gsens, implying that genetic confounding is present in the relationship between screen time and depressive symptoms in adolescents and young adults.",

keywords = "ALSPAC, depression, genetic confounding, screen time",

author = "Jiayao Xu and Jessie Baldwin and Hughes, \{Amanda M.\} and Annie Herbert and Jones, \{Hannah J.\} and Munafo, \{Marcus R.\} and Howe, \{Laura D.\}",

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doi = "10.1093/ije/dyag079",

language = "English",

volume = "55",

journal = "International Journal of Epidemiology",

issn = "0300-5771",

publisher = "Oxford University Press",

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T1 - Exploring genetic confounding of the associations between screen time and depressive symptoms in adolescence and early adulthood

AU - Xu, Jiayao

AU - Baldwin, Jessie

AU - Hughes, Amanda M.

AU - Herbert, Annie

AU - Jones, Hannah J.

AU - Munafo, Marcus R.

AU - Howe, Laura D.

PY - 2026/6/11

Y1 - 2026/6/11

N2 - Background: Digital devices have become a major aspect of children’s lives. Associations between screen time and mental health have been observed, but the causality remains unclear. This study aimed to investigate the associations between screen time and later depressive symptoms, and to test the robustness of these associations when accounting for genetic confounding. Methods: This study used data from the Avon Longitudinal Study of Parents and Children—a prospective cohort of children born between 1991 and 1992 in the UK. Different forms of screen time and depressive symptoms at ages 16, 22, and 26 years were assessed through self-completion questionnaires. The average daily screen time was calculated. Depressive symptoms were measured by using the Short Mood and Feelings Questionnaire (SMFQ). Polygenic scores (PGSs) for depression were calculated. Linear regression models were used to examine the associations between standardized screen time at ages 16, 22, and 26 years, and standardized depressive symptoms at age 26 years, adjusting for sociodemographic confounders and PGSs. Genetic sensitivity analysis (Gsens) was used to test for genetic confounding in these associations. Results: A total of 3003 participants were included in the analysis. Some, but not all, forms of screen time were associated with higher SMFQ scores, e.g. time spent using a phone, tablet, or e-book at age 22 years [β: 0.10, 95% confidence interval (CI) 0.07, 0.14 for weekdays; β: 0.08, 95% CI 0.04, 0.11 for weekends] and television time at age 26 years (β: 0.10, 95% CI 0.06, 0.14 for weekdays; β: 0.09, 95% CI 0.06, 0.13 for weekends). These associations persisted after adjustment for sociodemographic confounders and PGSs, but were attenuated in the Gsens (β = 0.03, 95% CI −0.01, 0.07 for the association with time spent using a phone, tablet, or e-book at age 22 years on weekends; β = 0.06, 95% CI 0.01, 0.10 for television time at age 26 years on weekends). Conclusion: For some measures of screen time, there were no associations with depressive symptoms. Where associations were seen, they were attenuated in the Gsens, implying that genetic confounding is present in the relationship between screen time and depressive symptoms in adolescents and young adults.

AB - Background: Digital devices have become a major aspect of children’s lives. Associations between screen time and mental health have been observed, but the causality remains unclear. This study aimed to investigate the associations between screen time and later depressive symptoms, and to test the robustness of these associations when accounting for genetic confounding. Methods: This study used data from the Avon Longitudinal Study of Parents and Children—a prospective cohort of children born between 1991 and 1992 in the UK. Different forms of screen time and depressive symptoms at ages 16, 22, and 26 years were assessed through self-completion questionnaires. The average daily screen time was calculated. Depressive symptoms were measured by using the Short Mood and Feelings Questionnaire (SMFQ). Polygenic scores (PGSs) for depression were calculated. Linear regression models were used to examine the associations between standardized screen time at ages 16, 22, and 26 years, and standardized depressive symptoms at age 26 years, adjusting for sociodemographic confounders and PGSs. Genetic sensitivity analysis (Gsens) was used to test for genetic confounding in these associations. Results: A total of 3003 participants were included in the analysis. Some, but not all, forms of screen time were associated with higher SMFQ scores, e.g. time spent using a phone, tablet, or e-book at age 22 years [β: 0.10, 95% confidence interval (CI) 0.07, 0.14 for weekdays; β: 0.08, 95% CI 0.04, 0.11 for weekends] and television time at age 26 years (β: 0.10, 95% CI 0.06, 0.14 for weekdays; β: 0.09, 95% CI 0.06, 0.13 for weekends). These associations persisted after adjustment for sociodemographic confounders and PGSs, but were attenuated in the Gsens (β = 0.03, 95% CI −0.01, 0.07 for the association with time spent using a phone, tablet, or e-book at age 22 years on weekends; β = 0.06, 95% CI 0.01, 0.10 for television time at age 26 years on weekends). Conclusion: For some measures of screen time, there were no associations with depressive symptoms. Where associations were seen, they were attenuated in the Gsens, implying that genetic confounding is present in the relationship between screen time and depressive symptoms in adolescents and young adults.

KW - ALSPAC

KW - depression

KW - genetic confounding

KW - screen time

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JO - International Journal of Epidemiology

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Exploring genetic confounding of the associations between screen time and depressive symptoms in adolescence and early adulthood

Abstract

Data Availability Statement

Acknowledgements

Funding

UN SDGs

Keywords

ASJC Scopus subject areas

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