summarize the only parts where it is related to the following: Health Concerns
Claim: Prolonged screen time leads to physical and mental health issues.
make a short and simple written summary: Background
Children’s screen time activity has increased significantly during the pandemic. Extended school closures and heightened parent stress are associated with children’s behavioural difficulties and time spent watching screens. The primary aim of this study was to determine which school and household factors were associated with challenging behaviours in Canadian schoolchildren during the COVID-19 pandemic.

Methods
This longitudinal survey study examined the association amongst screen time, internalizing and externalizing behaviours in school-aged children at two time points over the 2020–2021 academic school year. Parents completed survey measures on their parental involvement, stress levels, and their child’s screen time use as well as their emotional and behavioural difficulties.

Results
Children’s average daily screen time was 4.40 h (SE = 18.45) at baseline and 3.89 h (SE = 16.70) at 1-year follow up, with no significant change across the school year (p = .316). Increased screen time use was associated with a greater incidence of internalizing behaviours in children (p = .03). Children who spent more time on screens and who were in households with parents reporting higher stress levels had increased internalizing behaviours (p < .001). No association between screen time use and externalizing behaviours was evident; however, parent stress was positively associated with children’s externalizing behaviours (p < .001).

Conclusions
Children’s screen time use has remained high during the pandemic and is associated with anxious and depressive symptoms. Children who spent more time on screens and who were in households with parents reporting higher stress levels had increased internalizing behaviours. Parent stress was positively associated with children’s externalizing behaviours. Targeted family intervention plans focused on reducing parent stress and screen time use may aid in improving children’s mental health during the ongoing pandemic.

Keywords: Parent stress, Parental involvement, Screen time, Behavioural outcomes, Education

Introduction
The COVID-19 pandemic generated unprecedented increases in children and adolescents’ time spent on devices, with some children spending over 6 h per day on screens [1–4]. A parallel epidemic emerged in parents with school-aged children, who reported stress levels in the moderate to high range [3, 5, 6]. While screen time and parent stress are known to have separate adverse implications on childhood development [7–9], little is known about the accumulated risks of prolonged screen time exposure on incidences of internalizing and externalizing behaviours in children, and the moderating influence of parent stress and parenting strategies on these relationships.

Screen time is the amount of time spent using a device with a digitized interface, such as computers, television, video games, and smartphones [10]. Health care professionals caution that excessive screen time may adversely impact childhood development, health, and mental health outcomes with screen time guideline recommending a maximum of 2 h of screen time per day for children over the age of five [11, 12].

The unparalleled impact of COVID-19 engendered nationwide increases in children’s time spent on devices [1, 4, 13, 14]. Based on early cross-sectional data in Ontario, children’s average screen time increased from 2.6 h before the pandemic, to 5.9 h a day during the initial school closures of the pandemic [3]. This daily average is more than double the recommended guidelines for Canadian children. Similar increases occurred in the United States, Turkey, China, Italy, and Spain [1, 2, 4], with concurrent decreases in physical activity also found in some of these samples [4, 13]. Factors such as socioeconomic status, race/ethnicity, school satisfaction (for both children and parents), and having a child with special needs, contributed to unregulated screen time in children [2, 3, 15, 16].

The most prevalent mental health concerns affecting school-aged children prior to the pandemic were anxiety, depression, and conduct problems [17]. Since March 2020, internalizing (i.e., anxiety and depression) and externalizing problems (i.e., aggression) have increased dramatically in school aged children [18], with an estimated 20–25% of children experiencing symptoms of depression and anxiety [19]. Lockdowns were associated with the most pervasive emotional problems, including anxiety, restlessness, worry, and depression [13, 19].

Early evidence indicates that internalizing and externalizing problems may be an enduring issue for children and youth during the pandemic. Increases in internalizing and externalizing symptoms from pre-pandemic to the initial lockdown period were found in Canada and the United Kingdom [18, 20]. In a cohort of Norwegian children, an overall increase in mental health issues were reported during the early stages of the pandemic to 9 months after the initial outbreak, with internalizing symptoms accounting for the most increases [21]. Factors such as parent stress, intra-family dysregulation, and screen time contributed to increases in children’s mental health problems [6, 18, 22].

Excessive screen time use appears to have an adverse influence on children’s mental health outcomes [23–25]. In a large longitudinal study of brain development and child wellbeing in the United States (ABCD study; https://abcdstudy.org) increased screen time was associated with impaired social skills [26, 27], depression and anxiety [28], behavioural and social issues [29], and reduced sleep duration, fatigue, and insomnia in children [30]. Screen time was associated with a dose-dependent increase in depression risk in children [31]. Youth reporting over 4 h of passive screen time per day were significantly more likely to meet the criteria for major depressive episode, social phobia, and generalized anxiety disorder [32]. By contrast, a systematic review (n = 159, 425) on children’s screen time behaviours found that screen time was weakly associated with externalizing and internalizing problems [33]. Age-related factors appear to influence the strength and direction of the association [34].

Adverse mental health outcomes associated with unregulated screen time is an emergent concern amid the ongoing pandemic. Cross sectional evidence from early stages of the pandemic demonstrates associations between excessive screen time and increased incidence of total mental health difficulties in children and youth, with sleep duration, physical activity and sedentary behaviour mediating these relationships [25, 35]. In a cohort of 2026 Ontario children, more digital media and TV consumption was associated with conduct and hyperactivity/inattention problems in children under the age of 4 and internalizing problems in older children [36].

Parent mental health, parenting strategies, and involvement with children’s academic and recreational activities may mediate the association between excessive screen time use and mental health problems in children [3, 10, 37–39]. For example, in an Israeli cohort of parent-adolescent dyads, negative parenting practices significantly increased the risk of digital media addiction in children, which in turn was associated with behavioural and emotional problems [40]. In a Brazilian cohort, negative parenting strategies were associated with both poorer mental health in children, as well as increased screen time [22].

The pandemic has contributed to heightened perceived stress among parents with school aged children [3, 5, 13, 41], which may put children at risk for greater screen time use and mental health problems in the future [6, 42]. For example, greater parent anxiety during the initial COVID-19 outbreak was a significant predictor of children’s internalizing and externalizing behaviours [6]. In addition, over-reactive, inconsistent, and authoritarian parenting practices contributed to higher screen time use in children [1, 22].

While studies point to the separate negative influences of screen time and parent stress on children’s mental health outcomes, few studies have addressed these concerns longitudinally. The influence of parental stress and parenting strategies has been identified as important mediating factors on both screen use behaviours in children as well as emotional and behavioural outcomes. It is essential to identify the factors that promote or impede childhood development, and to devise early intervention strategies to support parents and children during periods of school closures.

In the current longitudinal study, we examined the association between screen time, parental involvement, and parent stress on the incidences of externalizing and internalizing behaviours in a cohort of Canadian children from November 2020 to November 2021. These time points encompass different school and public responses to COVID-19. In late 2020 to early 2021, much of Canada was under lockdown measures, resulting in school closures for in-person learning, and the closure of community and recreational centres. In late 2021, all adults were eligible for vaccination, schools across the country were open for in-person learning, and community and recreational centres were resuming activities. Using data gathered from these diverse time points, two research questions were examined: 1) Is screen time associated with internalizing and externalizing behaviours in children over time? 2) Will changes in parent stress and parental involvement affect the relationship between screen time and children’s mental health outcomes? We hypothesize that protracted screen time exposure will contribute to increased externalizing and internalizing behaviours, and that parent stress and parental involvement will moderate the strength of this association.

Methods