Screen time and green time are linked to psychological well-being in contrasting ways

Oswald, T. K., Rumbold, A. R., Kedzior, S. G. E., & Moore, V. M. (2020). Psychological impacts of "screen time" and "green time" for children and adolescents: A systematic scoping review. PLOS ONE, 15, 1-52. https://doi.org/http://dx.doi.org/10.1371/journal.pone.0237725

This systematic scoping review of the literature investigated association between screen time, green time, and psychological outcomes in children and adolescents. Screen time (ST) was defined as time spent engaging with visual screen-based technologies (including televisions, computers/laptops, videogames, smart phones, tablets/iPads, and handheld electronic or gaming devices); green time (GT), as exposure to or time spent in nature (including surrounding greenery, access to and use of green spaces like parks, nature-based activities such as gardening, and nature-based educational contexts such as greened schoolyards). Only studies using quantitative data and published in English peer-reviewed publications were included. Study participants were aged 18 years or younger and were not diagnosed with a mental, cognitive, or developmental disorder requiring clinical intervention.

A total of 186 studies met the inclusion criteria. Most of the studies were published in the last 10 years, and most were conducted in high-income countries. Over 60% of the studies were cross-sectional. Sample sizes ranged from 11 to more than 350,000 participants, with a median of 969. Of the different child-span age groups, adolescents were studied the most often.

Generally, high levels of ST were associated with unfavorable psychological outcomes, while GT tended to be associated with favorable psychological outcomes. Unfavorable psychological outcomes include such indicators of poor mental health as depression, anxiety, stress, psychological distress, poor self-regulation, emotional problems, and negative affect or mood. Favorable psychological outcomes include (a) indicators of positive mental health (happiness, resilience, hope, prosocial behaviors, positive affect, and self-esteem), (b) cognitive functioning (attention, working memory, and executive function), and (c) academic achievement (high grades, test scores, and grade point average). Different developmental stages were associated with different ST and GT exposures and outcomes. For example: for children under the age of 5, ST was most commonly explored in relation to cognitive and language development. For adolescents, ST was more often explored in relation to self-image. For GT, natural environments at home seemed to be more important for pre-school and school-aged children, while broader environments may be more important to early adolescents.

While few studies considered ST and GT together, and possible reciprocal psychological effects, some evidence indicates that GT could buffer negative consequences of high screen time. Nature may thus be “an under-utilised public health resource for youth psychological well-being in a high-tech era”. This may be especially important for young people living in low socioeconomic neighborhoods where ST tends to be higher and GT less accessible.

The need for further research is highlighted and suggestions for conducting such research are offered. “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”.

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