Last updated: Sep 19, 2016

Young adults who spend excessive amounts of time online may have higher rates of depression, anxiety, and attention deficit hyperactivity disorder (ADHD), according to a new Canadian study. The research also suggests that Internet addiction may be widely under-reported, and that commonly accepted diagnostic criteria may need to be revised to keep up with the changing role of the Internet in our lives.

The study, presented at the European College of Neuropsychopharmacology (ECNP) conference in Vienna, used two scales to evaluate Internet use: the commonly used and globally accepted Internet Addiction Test (IAT), and a newer scale designed by the authors.

The IAT was developed in 1998, before smartphones and tablets were such a prevalent part of society. “In addition, Internet use has changed radically over the last 18 years, through more people working online, media streaming, social media, etc.,” said lead author Michael Van Ameringen, MD, in a press release. Dr. Van Ameringen is a professor of psychiatry and behavioral neurosciences at McMaster University.

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“We were concerned that the IAT questionnaire may not have been picking up on problematic modern internet use,” he added, “or showing up false positives for people who were simply using the Internet rather than being over-reliant on it.”

So Dr. Van Ameringen and his colleagues recruited 254 college students and tested them for Internet addiction using both scales. They also asked the participants about their overall mental health and well-being.

According to the IAT, only 33 students met the criteria for Internet addiction. Based on the authors’ new questionnaire, however, 107 students—more than 40 percent—were considered to have problematic or addictive Internet use. (The latter number is closer to the results of another recent study, in which half of teens said they felt “addicted” to technology.) 

And when the researchers looked at how the Internet addicts by either set of criteria compared to the “normal” web users in several areas of mental health, they made some strong connections.

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“We found that those screening positive, on the IAT as well as on our scale, had significantly more trouble dealing with their day-to-day activities, including life at home, at work/school and in social settings,” Dr. Van Ameringen said. People with Internet addiction also had higher rates of depression and anxiety symptoms, problems with planning and time management, and higher levels of attentional impulsivity and ADHD symptoms.

“This leads us to a couple of questions,” said Dr. Van Ameringen: “Firstly, are we grossly underestimating the prevalence of Internet addiction and, secondly, are these other mental health issues a cause or consequence of this excessive reliance on the Internet?”

Larger clinical trials are needed to answer these questions, said Jan Buitelaar, MD, PhD, a member of an ECNP advisory panel on child and adolescent disorders, in the press release. But what’s clear, he added, is that large amounts of time spent online may disguise mild or severe mental health problems.

"Excessive use of the internet is an understudied phenomenon,” said Dr. Buitelaar, who is a professor of psychiatry at Radboud University in the Netherlands but was not involved in the study, adding that it “may be strongly linked to compulsive behaviour and addiction.”

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The researchers hope that their research one day helps mental health professionals diagnose and treat patients more accurately and effectively. For example, therapists may need to keep in mind that unhealthy Internet behavior may be triggered by another condition, or vice versa.

“If you are trying to treat someone for an addiction when in fact they are anxious and depressed, then you may be going down the wrong route,” says Dr. Van Ameringen.

Of course, this isn’t the first time that excessive use of technology has been linked to emotional problems. Another recent study on college students—a group that’s known for its near-constant digital connectedness—found that problematic cell-phone use was associated with lower levels of trust, and higher levels of alienation, within students’ family and social networks. In fact, the researcher suggested that using phones to surf the Web and use social media—rather than text or talk directly with personal connections—could be, at least partially, to blame.

This article originally appeared on RealSimple.com.