are phone-obsessed teens at greater risk of ADHD?

This week, news outlets across the world reported a study from the Journal of the American Medical Association (JAMA) linking digital media exposure to reduced attention spans and attention deficit/hyperactivity disorder (ADHD):

But while the study found a link between high rates of digital media use and inattention and hyperactivity, it didn’t find that one caused the other.

Read more: Clearing up confusion between correlation and causation

Nor did it look specifically at clinically diagnosed ADHD – it used a survey to ask students about ADHD-related symptoms.

What is ADHD?

ADHD is a neurodevelopmental disorder, which means it originates in early childhood and affects the brain’s development. Around 7.2% of children worldwide have a diagnosis of ADHD.

Symptoms include inattentive, hyperactive and impulsive behaviour. Although characteristic of ADHD, these behaviours exist on a continuum. So attention difficulties can be experienced, though at a lesser degree, by children and adolescents who don’t have ADHD.

These behaviours may fluctuate due to factors such as age (they’re more common in childhood) and levels of stress.

Read more: Imaging study confirms differences in ADHD brains

How was the study conducted?

The new JAMA study, from researchers at the University of Southern California, investigated the link between digital media use and the development of ADHD-related behaviours among 15- and 16-year-olds.

Just over 2,500 Californian high school students without ADHD completed a survey about their frequency of digital media use: many times a day, 1-2 times a day, 1-2 times a week, never.

The survey asked about 14 different types of use, including texting, checking social media sites, chatting online and streaming television on computers, smartphones and consoles. Participants rated their use for each type of media over the past week.

Every six months over the following two years, from 2014 to 2016, the students rated how frequently they experienced ADHD-related behaviours.

The researchers used an 18-question self-report scale, based on the criteria for diagnosing ADHD from the Diagnostic and Statistical Manual of Mental Disorders – 4th Edition (DSM-IV). Questions covered a range of difficulties, such as making careless mistakes, having difficulty sustaining attention, feeling restless, and interrupting others.

What did they find?

Most students (80.9%) reported high-frequency use (three or more times a day) of at least one type of digital media. Checking social media sites was the most common, with 54% of the teens checking in many times a day.

Over the first six months of the study, 6.9% of students reported they had experienced ADHD symptoms. This rate dropped to 5.9% over the last six months of the study.

Teens who reported no high-use digital media activity had lower rates of experiencing ADHD-related behaviour over the 24-month study period, at a rate of 4.6%.

High-frequency engagement with more digital activities was associated with higher odds of experiencing ADHD-related behaviour. Among those who reported high use of seven activities, 9.5% experienced ADHD-type behaviours. Those reporting high use of all 14 digital media activities had the highest rates, at 10.5%.

Not all high-frequency digital media activities were associated with ADHD symptoms. Texting, chatting online, playing games with friends or family on a console, computer or smartphone, and posting photos or blogs had no association.

Activities that had the strongest association with ADHD symptoms include a high frequency of checking of social media sites, liking or commenting on other statuses, playing games alone on a console, computer or smartphone, and video chatting.

Two other factors – delinquent behaviour and depressive symptoms – were associated with higher rates of ADHD-related behaviours. But the link between high frequency of use of digital media and higher odds of ADHD symptoms held, even when taking these other factors into account.

What does it all mean?

This study highlights a potential association between digital media and behavioural symptoms typically associated with ADHD. But this work is unable to show causation.

Read more: How parents and teens can reduce the impact of social media on youth well-being

It’s not possible to determine whether digital media use exacerbates ADHD-related behaviour, or whether those with ADHD-related behaviours find digital media more attractive, and use it more frequently.

Despite a link between digital media use and behaviours that are common in ADHD, ADHD is a complex neurodevelopmental disorder, and these findings in no way suggest digital media can cause ADHD.

There is a strong genetic basis for ADHD. In other words, people with the disorder are more likely than their peers to have parents and siblings with ADHD.

It’s also important to note an increase in inattention and hyperactivity in adolescence does not mean the young person would be diagnosed with ADHD.

What else do we need to take into account?

More research is needed to fully understand the potential long-term negative and positive impacts digital media has on the way we think and behave.

For people who may be more likely to engage with digital media, such as those with ADHD, it’s important to assess whether this type of technology exacerbates existing clinical attention difficulties.

As is the case with most longitudinal studies (tracking large groups of participants over time), it’s difficult to control for all potential confounding factors. Significant life changes such as moving house, starting a new school, or bereavement can influence our behaviours and cognition.

The JAMA study did highlight two factors that impacted on the prevalence of ADHD symptoms – depression and delinquency – but it’s difficult to rule out other things that may be responsible.

Read more: How teens use fake Instagram accounts to relieve the pressure of perfection

It’s also possible digital media itself may not be directly causing negative effects but, rather, the time spent using entertainment-based digital media detracts from time spent on learning or leisure activities.

The current study only examined social and entertainment-based digital media. We need further investigations that examine the effect of a wider range of digital media on our health. – Hannah Kirk

Blind peer review

This Research Check is a fair and accurate assessment of the research demonstrating a link between digital media use and ADHD, highlighting the need for future research that identifies the direction and mechanism of causality. – Lisa Williams

Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one academic not involved with the study, and reviewed by another, to make sure it’s accurate.