A Canadian study published in the Journal of the American Medical Association (JAMA) Pediatrics on July 15 reveals sound evidence that adolescents who spend more time engaged in certain screen activities suffer increased depression.

Depression is a serious concern for adolescents and those who live and interact with them. Across gender, socio-economic and race demographics, 7 in 10 U.S. teens recently reported depression and anxiety as major issues among their peers and within their community, according to a Pew survey released earlier this year.

Estimates from the National Institutes of Health show that during 2017 a staggering 2.3 million adolescents aged 12 to 17 had at least one major depressive episode with severe impairment. That translates to 9.4% of the United States population for that age group.

Teenage depression is an equally critical issue in Canada, where the study was conducted by lead author Elroy Boers, Ph.D., from the University of Montreal.

According to the Canadian Mental Health Association approximately 5% of males and 12% of females in the 12 to 19 age group have experienced a major depressive episode. Suicide rates among 15- to 19-year-olds are slightly higher in Canada, according to an OECD report based on 2014-15 statistics.

The study adds clarifying evidence to prior research linking increasing teenage depression with technology use.

Study provides wider scope than previous research on screen time

The study included 3,826 adolescents from 31 schools in the Montréal metropolitan area — a very large sample size when compared to prior studies. The students were selected as part of an unrelated randomized clinical trial assessing the efficacy of a personality-targeted drug and alcohol program.

Unlike other research, the study spanned four consecutive years and examined data from the same teenagers beginning when they were 12-13 years old. This allowed researchers to correlate the time spent on screens with degree of depression within the same individual as well as making comparisons with different people.

The study was also unique in that it distinguished between four types of screen use. Students answered questions about the amount of time they spent daily doing each of the following: viewing social media, watching television, playing video games, and being on the computer.

To gauge depression students filled out a version of the Brief Symptoms Inventory, selecting on a scale of 0 to 4 the extent they were experiencing different emotions or thoughts. Among the seven symptoms of depression found in the mix were having thoughts of ending your life; feeling lonely; feeling no interest in things; feeling hopeless about the future; and feeling worthless.

Surprising and not-so-surprising results of the study

Independent of media use, the adolescents’ level of depression increased over the course of the four years. Girls, along with individuals who reported lower socio-economic status, demonstrated more severe symptoms overall.

Results that compared the four different screen options showed that youth who spent more time on social media or computers initially reported a higher level of depressive symptoms than those spending more time playing computer games and watching television.

When responses for each individual were compared over the four years, researchers noted that with each hour per day of increased social media and television exposure students reported a significant increase in depressive symptoms.

Teens who used their computers more over the years didn’t report higher depression levels. The same was true for video game playing.

Of the four screen types, video game playing was the only one that showed no correlation with depression in the study.

Depression increases more when channel promotes comparison

To explain their findings, researchers examined the data with three hypotheses in mind.

First, they considered displacement theory, meaning the time spent on screens is taking the place of other healthier activities like exercise. Given that time spent playing video games showed no association with depression, the results of the study did not support this hypothesis, according to the researchers.

They also looked at reinforcing spirals theory, where the individual’s use of technology and their choices reflect the emotional state they are already in — then serves to reinforce it.

Researchers concluded that the results pointed most strongly to the third possible explanation, upward social comparison, which occurs when people compare themselves with others they believe are in a better position.

Both social media and television promote exposure to idealized images such as people enjoying perfect lives and having perfect bodies. Accordingly, the study data demonstrated that for every additional unit of time teens spent engaged in these two media, a similar increase in depression was registered.

To explain the mixed results for computer use, researchers write, "It seems that over time, adolescents gain more computer experience, which may positively affect their self-efficacy, in turn resulting in less severe symptoms of depression."

Study answers a few questions, but more need to be answered

The study allowed researchers to measure levels of depression associated with different types of screen time. However, they recommend further research, including the content the teens are interacting with in order to make more conclusive associations between screen time and depression.

Along with providing insight, the study exposes questions that warrant future investigation.

For example, why is depression increasing across the board as teens get older? What is happening for girls and students who have lower incomes? Although it isn’t associated with depression, is video game playing harmless for teens?

Just as critically, what role can educators, counselors, healthcare providers and parents play in addressing adolescent depression? And how can this information be used to guide teens in making choices that better support their emotional well-being?