Relationship between screen time and mental health


Boys who regularly play video games at age 11 are less likely to develop depressive symptoms three years later, finds a new study led by a UCL researcher.

The study, published in Psychological Medicine, also found that girls who spend more time on social media appear to develop more depressive symptoms.

Taken together, the findings demonstrate how different types of screen time can positively or negatively influence young people’s mental health, and may also impact boys and girls differently.

Lead author, Ph.D. student Aaron Kandola (UCL Psychiatry) said: “Screens allow us to engage in a wide range of activities. Guidelines and recommendations about screen time should be based on our understanding of how these different activities might influence mental health and whether that influence is meaningful.

“While we cannot confirm whether playing video games actually improves mental health, it didn’t appear harmful in our study and may have some benefits. Particularly during the pandemic, video games have been an important social platform for young people.

“We need to reduce how much time children – and adults – spend sitting down, for their physical and mental health, but that doesn’t mean that screen use is inherently harmful.”

Kandola has previously led studies finding that sedentary behaviour (sitting still) appeared to increase the risk of depression and anxiety in adolescents. To gain more insight into what drives that relationship, he and colleagues chose to investigate screen time as it is responsible for much of sedentary behaviour in adolescents.

Other studies have found mixed results, and many did not differentiate between different types of screen time, compare between genders, or follow such a large group of young people over multiple years.

The research team from UCL, Karolinska Institutet (Sweden) and the Baker Heart and Diabetes Institute (Australia) reviewed data from 11,341 adolescents who are part of the Millennium Cohort Study, a nationally representative sample of young people who have been involved in research since they were born in the UK in 2000-2002.

The study participants had all answered questions about their time spent on social media, playing video games, or using the internet, at age 11, and also answered questions about depressive symptoms, such as low mood, loss of pleasure and poor concentration, at age 14. The clinical questionnaire measures depressive symptoms and their severity on a spectrum, rather than providing a clinical diagnosis.

In the analysis, the research team accounted for other factors that might have explained the results, such as socioeconomic status, physical activity levels, reports of bullying, and prior emotional symptoms.

The researchers found that boys who played video games most days had 24% fewer depressive symptoms, three years later, than boys who played video games less than once a month, although this effect was only significant among boys with low physical activity levels, and was not found among girls.

The researchers say this might suggest that less active boys could derive more enjoyment and social interaction from video games.

While their study cannot confirm if the relationship is causal, the researchers say there are some positive aspects of video games which could support mental health, such as problem-solving, and social, cooperative and engaging elements.

There may also be other explanations for the link between video games and depression, such as differences in social contact or parenting styles, which the researchers did not have data for. They also did not have data on hours of screen time per day, so they cannot confirm whether multiple hours of screen time each day could impact depression risks.

The researchers found that girls (but not boys) who used social media most days at age 11 had 13% more depressive symptoms three years later than those who used social media less than once a month, although they did not find an association for more moderate use of social media.

Other studies have previously found similar trends, and researchers have suggested that frequent social media use could increase feelings of social isolation.

Screen use patterns between boys and girls may have influenced the findings, as boys in the study played video games more often than girls and used social media less frequently.

The researchers did not find clear associations between general internet use and depressive symptoms in either gender.

Senior author Dr. Mats Hallgren (Karolinska Institutet) has conducted other studies in adults finding that mentally-active types of screen time, such as playing video games or working at a computer, might not affect depression risk in the way that more passive forms of screen time appear to do.

He said: “The relationship between screen time and mental health is complex, and we still need more research to help understand it. Any initiatives to reduce young people’s screen time should be targeted and nuanced. Our research points to possible benefits of screen time; however, we should still encourage young people to be physically active and to break up extended periods of sitting with light physical activity.”

The prevalence of mental illness among children and adolescents is increasing globally [1–3]. In particular, depression and anxiety are leading causes of reduced quality of life among children and adolescents [4–8]. Experiences of depressive and anxiety symptoms in childhood and adolescence are associated with an elevated risk of poor mental health in adulthood [8–12], suggesting enduring consequences of compromised mental health while young for well-being and functioning across the lifespan.

Given these lifelong impacts, there is a pressing need to identify and address upstream determinants of mental health, focussing on the prevention of mental illness alongside the promotion of mental well-being. This scoping review focuses on two emerging determinants of interest: time spent engaging with screen-based technologies, referred to as ‘screen time’ (ST), and exposure to or time spent in nature, referred to as ‘green time’ (GT).

With rapid technological developments making access to electronic devices and their presence in our lives pervasive, concern is mounting about the psychological impact of prolonged ST, particularly in children and adolescents [13–18]. A decade ago in a U.S. sample of 8-to-18 year olds, the average ‘total screen time’ was reported at 7.5 hours a day [19] and was highest in 11-to-14 year old adolescents (9 hours). This greatly exceeds recreational ST guidelines of 2 hours or less per day [20]. With widespread integration of digital technologies in school curricula [21], ST is no longer confined to recreational use, making it an inevitable part of young peoples’ lives.

Moderate ST can be beneficial for young people in a connected world [22] as it may afford them with opportunities to enhance existing relationships, forge new connections, engage in safe identity exploration, aid in academic pursuits, and provide access to information about the world beyond their immediate surroundings [23].

However, from a developmental neurobiology perspective, excessive ST may be detrimental to young people as ST stimulates neurobiological systems such as the hypothalamic-pituitary-adrenal (HPA) axis [24] and dopaminergic circuitries [25]. Childhood and adolescence are sensitive periods in which these systems develop and change [26–29], making them particularly vulnerable to insult.

From a lifestyle and social perspective, it has been argued that excessive ST also displaces important protective behaviours for mental health such as physical activity [30, 31], getting adequate sleep [32], in-person social interactions [33], and academic activities [34].

As ST has increased, regular engagement with natural environments has concurrently decreased among young people. Children in high-income countries are now experiencing significantly lower levels of contact with nature, or GT, than previous generations [35, 36].

For example, twelve-year-old children in the U.S. report spending an average of less than 6 hours per week outdoors [37], which is less than the average daily screen time for young people. Similarly, in England fewer than a quarter of children reported regularly visiting their local ‘patch of nature’ and less than one in ten children reported regularly playing in wild places, compared to half of all children in the previous generation [38].

Likewise, in a survey of Australian adults, 73% reported playing outdoors more often than indoors when they were children, compared to only 13% of their own children today [39]. Young people’s time spent in nature has been strongly influenced by rapid urbanisation which in many nations has reduced access to both urban greenspaces and private gardens [40].

Benefits of natural environments could be gained through increased physical activity [41, 42] and social connections experienced in greenspaces like parks [41, 43]. Natural areas also tend to be less crowded, with reduced air and noise pollution, which is beneficial for overall health [41].

Furthermore, time spent exposed to natural sunlight helps to regulate circadian rhythms, encouraging healthy sleep-wake cycles and improved sleep [44], which is key for psychological well-being. Several theories within evolutionary and environmental psychology propose that engagement with natural environments is directly beneficial for human health and well-being [45, 46]. Notably, Kaplan’s Attention Restoration Theory postulates that nature has specific restorative effects on cognitive functioning [46, 47] and Ulrich’s Stress Reduction Theory contends that nature induces positive affect through reduced stress [45].

Experiences of ST and GT appear to influence psychological well-being in contrasting ways. Screen-based technologies are stimulating and extensive use can potentially displace important protective behaviours, thus they may be detrimental to psychological well-being. Conversely, natural environments may facilitate attention restoration and stress reduction, and support a range of behaviours that promote psychological well-being.

As such, it may be argued that the combination of increased ST and decreased GT may be harmful for young people’s mental well-being, and increasing GT may serve as an important ameliorator of ST, to promote mental well-being in an inevitably high-tech era. This may be particularly important for children and adolescents from low socioeconomic backgrounds, who typically engage in greater amounts of ST [48–51] and are also less likely to live in green neighbourhoods [52].

However, research investigating the psychological impacts of ST or GT typically considers ST and GT in isolation and fails to delineate the reciprocal effects of high technology use and low contact with nature on mental health and cognitive outcomes [53].

Such research could give us a greater understanding of 21st century drivers of youth well-being and guide recommendations regarding ST and GT for optimal psychological functioning. We are not aware of any previous review that has attempted to collate evidence about the effects of both of these exposures on child and adolescent psychological outcomes.

This scoping review has four aims:

  1. To describe the international literature and evidence regarding the impact of ST and/or GT on psychological outcomes in children and adolescents;
  2. To explore the basis for inference about causal links between ST, GT, and psychological outcomes for children and adolescents;
  3. To explore the extent to which findings hold, or vary, across the spectrum of socioeconomic status;
  4. To investigate the extent to which studies have attempted to delineate the reciprocal effects of ST and GT on psychological outcomes in children and adolescents.

Key definitions
The literature exploring the effects of ST and GT on psychological outcomes in children and adolescents is plagued with inconsistent terminology and calls for clarification and consistency. Therefore, this review will operationalise the following constructs as defined below:

Screen time

Screen time (ST) refers to time spent engaging with visual screen-based technologies such as televisions, computers/laptops, videogames, smart phones, tablets/iPads, and handheld electronic or gaming devices. Using the Internet, social media, or communicating via text message are all activities which are included in the definition of ST. Solely auditory activities, such as talking on a phone and listening to music, are not included.

Green time

For the purposes of this review, green time (GT) is broadly defined as time spent in, or exposure to, natural environments, elements, or content. This can be further specified as

  • (a) incidental exposure to green space and/or natural elements, as measured by residential greenness or level of greenness surrounding schools and commuting environments;
  • (b) accessibility to green spaces, public parks, open public spaces, private gardens, or green infrastructure;
  • (c) purposive use of green spaces, public parks, private gardens, or green infrastructure;
  • (d) activities centred around nature such as wilderness expeditions, gardening, horticultural activities, surfing, or outdoor play; and
  • (e) educational contexts such as education outside the classroom or forest schools and kindergartens.

Both the quantity and quality of GT may be considered, which includes attending to the size of green spaces or duration of time spent in green spaces, along with the level of naturalness or specific features of the environments under investigation. A definition of this breadth is necessary given the heterogeneity of existing definitions and lack of consistency when considering GT in the literature.

Psychological outcomes
For the purpose of this review, psychological outcomes is a summary term which encapsulates four constructs, measuring a range of psychological variables, including

  • (a) indicators of poor mental health,
  • (b) indicators of positive mental health,
  • (c) cognitive functioning, and
  • (d) academic achievement (Table 1).

We have included academic achievement in our scoping review given it can be an indicator of positive psychological functioning [54], integrating aspects of cognitive control such as self-regulation [55], attention [56], executive functions, and working memory [57].

Table 1

Psychological outcomes included in the review.

Indicators of Poor Mental HealthCommon internalising or externalising disorders2 or their symptoms, such as:
• Depression
• Anxiety
• Stress
• Psychological distress
• Poor self-regulation
• Emotional problems
• Psychological difficulties
• Psychosomatic symptoms
• Negative affect or mood
Indicators of Positive Mental HealthRefers to elements of positive psychology or overall well-being, such as:
• Happiness
• Resilience
• Satisfaction with life
• Quality of life
• Health-related quality of life
• Self-esteem
• Optimism
• Positive affect or mood
• Hope
• Prosocial behaviour
Cognitive FunctioningRefers to mental processes, such as:
• Attention
• Working memory
• Executive function
• Visual, spatial, verbal, language, and cognitive development
Academic AchievementRefers to school measures, such as:
• Subject grades
• Grade point averages (GPA)
• Test or examination results


While moderate ST can be beneficial for young people in a connected world, it is widely speculated that the concomitant trends of increasing ST and decreasing GT among children and adolescents may be social determinants of trends in youth mental health problems. However, research rarely considers the reciprocal effects of extensive ST (which is arguably detrimental) and GT (which is arguably protective) on children and adolescents’ psychological well-being.

Researchers should move beyond cross-sectional studies, to longitudinal and intervention studies which are designed to investigate the psychological effects of both ST and GT, with careful specification of the extent and type of exposure. Research should consider specific developmental ages of children and adolescents, young people from low SES backgrounds, and consider the specific contribution of other lifestyle variables. GT presents as a potentially novel strategy to ameliorate high levels of ST; however, robust evidence is needed to guide policies and recommendations for exposure at critical life stages in childhood and adolescence. Nature may currently be an under-utilised public health resource, and it could potentially function as an upstream preventative and psychological well-being promotion intervention for children and adolescents in a high-tech era.

reference link:

More information: Psychological Medicine (2021). DOI: 10.1017/S0033291721000258


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