Scientists trace a neurodevelopmental link between infant screen time and teenage anxiety

An analysis of the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) data found that higher infant screen time was associated with higher deliberation time needed in a neuropsychological task at 8.5 years of age. Individuals with higher deliberation time in this task tended to show greater anxiety symptoms at age 13. The paper was published in eBioMedicine.

In modern society, devices using screens are present everywhere. Globally, the amount of time young children spend on screens is increasing. Studies indicate that infants generally engage in 2 to 3 hours of daily screen time. This is much more than health authorities, such as the World Health Organization, recommend.

The time spent using screens is particularly concerning in the first two years of life when critical brain development processes occur. Brain volume doubles in the first year, and it increases by an additional 15% to 80% in the second year of life. Many studies so far have linked longer times spent using screens with less desirable outcomes in cognitive development, such as lower integration between the cognitive control and emotion processing networks, or a worse condition of the white matter tracts in the brain that support language and reading abilities.

Lead study author Pei Huang and his colleagues wanted to assess the directional association between infant screen time, the development of brain network topology, decision-making behavior, and anxiety symptoms in adolescence. They hypothesized that infant screen time would predict alterations in the developmental trajectory of network integration between some brain regions. They then hypothesized that these neural changes would relate to decision-making behavior later in life, and that changes to decision-making behavior would subsequently predict anxiety symptoms in adolescence.

The study authors analyzed data from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) study. GUSTO is an ongoing longitudinal birth cohort in Singapore that aims to investigate developmental influences on later life health outcomes. This study used data from 168 children enrolled in GUSTO for whom both screen time data and magnetic resonance imaging (MRI) data were available. Roughly 54% of these children were boys.

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Data on children’s screen time were collected using questionnaires from their parents when the children were 1 and 2 years old. At 4.5, 6, and 7.5 years of age, the children underwent MRI scans of their brains. At 8.5 years of age, the children completed the Cambridge Gambling Task, a sub-test of the Cambridge Neuropsychological Test Automated Battery (CANTAB).

The Cambridge Gambling Task is a computerized neuropsychological task in which participants choose between colored options with known probabilities and wager points on their choice. This allows for the assessment of quality of decision-making, impulsivity (delay aversion), risk-taking, risk adjustment, and overall betting proportion. One of the key measures provided by this test is deliberation time, which is the latency between the start of a trial and the child making a decision. Later, when the participating children were 13 years old, they completed a self-reported assessment of anxiety (the Multidimensional Anxiety Scale for Children).

Results showed that screen time in infancy was associated with the developmental trajectory of visual-cognitive network integration between 4.5 and 7.5 years of age. More specifically, children who spent more time using screens as infants tended to have a steeper decrease in visual-cognitive control network integration during this developmental window. Interestingly, screen time at ages 3 to 4 was not significantly associated with the integration level of these networks, highlighting infancy as a uniquely sensitive period.

Visual-cognitive control network integration reflects the structural connectivity between regions of the brain that process vision and brain networks responsible for higher-order cognitive control. As development proceeds, neural systems naturally tend to become more specialized, with stronger within-network connectivity and relatively weaker integration between different networks. Because of this, a steeper, faster decline in integration is interpreted as accelerated maturation of the brain.

The study authors next tested a statistical model proposing a “domino effect”: a steeper decline in the integration of the visual and cognitive control networks between 4.5 and 7.5 years of age leads to more deliberation time needed on the Cambridge Gambling Task at 8.5 years of age, which, in turn, leads to higher anxiety at 13 years of age. Results confirmed this full serial mediation pathway.

“Higher infant screen time is linked to accelerated topological maturation of the visual and cognitive control networks, leading to prolonged decision latency and increased adolescent anxiety. Sensory processing impairment may underlie this novel neurodevelopmental pathway, highlighting a potential target for early intervention,” the study authors concluded.

The study contributes heavily to the scientific understanding of the neural and developmental correlates of anxiety. However, it should be noted that the design of this observational study does not allow for definitive causal inferences.

Additionally, the researchers point out that they only measured total screen time, without differentiating the content of the media consumed or the context (such as whether a parent was watching and interacting with the child). Therefore, it remains possible that some of the negative effects of screen time are indirectly caused by a displacement of crucial parent-child interactions.

The paper, “Neurobehavioural links from infant screen time to anxiety,” was authored by Pei Huang, Shi Yu Chan, Kathy Xinzhuo Zhou, Jasmine Chuah, Aisleen Mariz Arellano Manahan, Evelyn Chung Ning Law, Shefaly Shorey, Helen Juan Zhou, Marielle Valerie Fortier, Yap-Seng Chong, Michael Joseph Meaney, and Ai Peng Tan.