Summary: Two or more hours of daily screen time is associated with increased inattention and other clinically significant behavioural problems in preschool-aged children.
Source: University of Alberta
Overview: A Canadian study of more than 2,400 families found that preschool children who spend two hours or more per day using screens are significantly more likely to show behavioural and attention problems by age five. The research, based on the CHILD Cohort Study, links higher screen exposure in early childhood with clinically meaningful increases in inattention and symptoms consistent with attention deficit hyperactivity disorder (ADHD).
Compared with children who had less than 30 minutes of screen time per day, those exposed to more than two hours daily were about five times more likely to display clinically significant externalizing problems—behaviours such as inattention—and more than seven times more likely to meet criteria consistent with ADHD symptoms. The study was led by Piush Mandhane, associate professor of pediatrics at the University of Alberta, and published in the journal PLOS ONE.
Mandhane emphasized that the results suggest current guidelines could be tightened. “We found that screen time had a significant impact at five years of age,” he said. “Current Canadian guidelines recommend no more than two hours a day at this age, but our findings indicate that even less screen time is preferable.”
The study used data from the CHILD (Canadian Healthy Infant Longitudinal Development) Cohort Study, a national birth cohort that follows families from pregnancy through childhood to track health, lifestyle, genetic, and environmental factors. Parents provided detailed reports of their child’s daily total screen time, including television, DVDs, computers, game consoles, smartphones, and tablets.
On average, three-year-olds in the sample had 1.5 hours of screen time per day; 42% exceeded the Canadian guideline of under one hour per day for that age. At age five, the average daily screen time was 1.4 hours, and 13% exceeded the recommended limit of under two hours per day.
Child behaviour and attention at age five were evaluated using the Child Behavior Checklist (CBCL), a widely used parent-report screening tool that measures problems such as anxiety, depression, emotional reactivity, inattention, aggression, and sleep disturbances. The researchers applied multiple linear and logistic regression models to examine associations between screen exposure and externalizing behaviours, inattention, and clinically significant symptom thresholds (CBCL T-score ≥ 65).
Sukhpreet Tamana, the study’s first author and a postdoctoral fellow in pediatrics at the University of Alberta, noted the practical implications. “Prior to this, there were limited data addressing questions like ‘How much is too much?’ and ‘Will limiting screen time in the preschool years benefit development?’ This analysis gives parents clearer, evidence-based guidance.”
Tamana highlighted two key findings: children exposed to greater screen time at either three or five years showed significantly more behavioural and attention problems at age five, and the strength of this association exceeded that of other measured risk factors, including sleep quality, parenting stress, and socioeconomic status.
The study also identified protective factors. Good-quality sleep was associated with a modest reduction in risk, while participation in organized sports showed a strong protective effect. Importantly, it was structured, organized activity—not just unstructured physical play—that most strongly lessened the likelihood of behavioural problems. “Many skills developed through organized activities—routine, social expectations, and structured interaction—appear to support healthy behavioral development,” Mandhane explained.
Although the research found clear links between total screen time and inattention, it did not determine whether the type of media content (educational programming, video games, social media) or the specific device used (television, computer, tablet) influenced outcomes. The research team plans to analyze content and device-specific effects in future studies.
Mandhane and colleagues do not call for a complete ban on screens. Rather, their data suggest an optimal range of zero to 30 minutes per day for preschoolers and reinforce that the preschool period is an important window to establish healthy habits around screens. “This is an ideal time to teach children healthy relationships with screens,” Mandhane said. “Our findings indicate it’s never too early to start.”
Institution: University of Alberta
Media contact: Ross Neitz – University of Alberta
Original research: Open access. Title: “Screen-time is associated with inattention problems in preschoolers: Results from the CHILD birth cohort study.” Authors include Sukhpreet K. Tamana, Victor Ezeugwu, Joyce Chikuma, Diana L. Lefebvre, Meghan B. Azad, Theo J. Moraes, Padmaja Subbarao, Allan B. Becker, Stuart E. Turvey, Malcolm R. Sears, Bruce D. Dick, Valerie Carson, Carmen Rasmussen, CHILD study Investigators, Jacqueline Pei, and Piush J. Mandhane. Published in PLOS ONE.
Abstract (summary): Preschool children average roughly two hours per day using screens. This analysis used parent-reported screen-time and CBCL results from the CHILD cohort to examine whether higher screen exposure is associated with worse behavioural outcomes. Screen-time data were available for over 95% of children with CBCL information (2,322 of 2,427). Mean daily screen-time was 1.4 hours (95% CI 1.4–1.5) at age five and 1.5 hours (95% CI 1.5–1.6) at age three. Compared with children with less than 30 minutes per day, those with more than two hours per day (13.7% of the sample) had a 2.2-point higher externalizing T-score (95% CI 0.9–3.5) and a five-fold increase in the odds of clinically significant externalizing problems. Children with more than two hours daily were 5.9 times more likely to show clinically significant inattention (95% CI 1.6–21.5) and had a 7.7-fold increased risk of meeting the clinical cutoff for ADHD-type symptoms (95% CI 1.6–38.1). There was no significant association between screen time and aggressive behaviours.
Conclusion: Higher screen time in the preschool years is associated primarily with increased inattention and related externalizing problems. Encouraging structured, non-screen activities—especially organized sports—and promoting healthy sleep patterns may help mitigate these risks.