Research shows a link between screen time and unhappiness in children.

Many parents are concerned about how much time their children spend on cellphones, Xboxes and other digital media. Some experts say they should be: There is a growing body of research showing an association between unhappiness and the time adolescents spend on digital media.

What is less clear is whether screen time is causing mental-health problems or if children with worse mental health spend more time with digital media.

To assess the research, we went to Jean Twenge, author of the book “iGen: Why Today’s Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy—and Completely Unprepared for Adulthood—and What That Means for the Rest of Us”; Michael Rich, founder and director of the Center on Media and Child Health in Boston and an associate professor at Harvard Medical School; and Cara Booker, research fellow and acting graduate director at the University of Essex in the U.K., who has studied the effects of social-media use on children and adolescents.

Edited excerpts follow:

WSJ: What does the evidence tell us about the links between screen time and children’s mental health?

DR. RICH: Perhaps the question should be whether screen use can be problematic for mental health. In an era when educational technology has deeply penetrated our schools—even preschoolers are handed tablets now—there are screens in all public places, and virtually everyone has interactive screen media at home and in their pockets, the concept of screen time as something that could be controlled is obsolete.

With one exception, screen time is less important to mental health than screen content and the context in which it is consumed and created. It is what children and adolescents are exposed to and encouraged to do with screens that helps or harms.

Where screen time becomes an issue is when it is displacing more productive or meaningful activities. For some young people, screen time can become compulsive, taking up more of their waking hours until they are functionally impaired. My colleagues and I describe this as Problematic Interactive Media Use, or PIMU, and over the past five years, we have seen a dramatic increase in young people whose gaming, social media, pornography or information-bingeing has resulted in sleep deprivation, school failure, relationship problems, anxiety and depression. As a result, we have founded a clinic at Boston Children’s Hospital for children and adolescents with PIMU and other media-related disorders.

DR. BOOKER: Most of the research that I focus on looks at social-media use and mental health, and unfortunately the findings are mixed. There are some studies that find either positive or no effects of social media. Others find negative effects. Much of this debate surrounds the question of time versus content. Some studies look at time and find negative effects, while others examine content and find lesser effects.

Jean Twenge
Jean Twenge Photo: Sandy Huffaker, Jr.

Jean Twenge Photo: Sandy Huffaker, Jr.

DR. TWENGE: Several large studies show that use of digital media beyond two hours a day of free time, and especially beyond four hours a day, is correlated with more depression and unhappiness in teens. Several longitudinal studies show this, as well, with children, teens, and young adults who spend more time on digital media later showing more mental-health issues. Sheer amount of time with screens, not just content, does matter, probably because those higher levels of use are enough to displace time spent on more beneficial experiences such as face-to-face interaction. It also is well-documented that digital media can displace or disrupt sleep; that alone could explain the link with compromised well-being.

Many of the mixed findings in the field are explained by two factors. First, some find links between positive experiences online and positive well-being, which isn’t surprising and isn’t the same thing as time spent online. Second, most studies don’t control for level of face-to-face social interaction. The same teens who spend more time with their friends in person are often those who are active on social media, so if that isn’t controlled for it can wash out the effect on well-being. We found, for example, that the most unhappy teens were those who spent more time than average with digital media and less time than average on face-to-face social interaction.

WSJ: What are the main weaknesses of the research so far?

DR. BOOKER: We haven’t fully explored the mechanisms through which screen use and children’s mental health are related. As has been mentioned, sleep is a large part of it. But there are other factors such as self-esteem, cyberbullying, body image, etc. that haven’t been fully addressed. I also don’t think that we have explored gender, cohort or ethnic differences enough and whether those exist. For example, in my research we found a relationship between social-media use and mental health among girls but not boys. [Ten-year old girls who used more social media were at higher risk of poorer well-being by age 15, according to Dr. Booker’s analysis of the Understanding Youth survey of 9,859 10- to 15-year-olds, 49% of whom were female.]

Is screen time just displacing any activity or specific ones that may lead to worse well-being? Also, if we are going on the broader topic of screen time, how do these interact with each other to affect mental health? Many young people multitask and use more than one screen to do different things. Is this substantially worse…

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Mayra Rodriguez

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Mayra Rodriguez
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