A survey found that people who use the internet more can also have more mental health problems. The findings were presented at the 29th European College of Neuropsychopharmacology (ECNP) conference in Vienna.

Researchers from the McMaster University in Canada used two scales to analyze internet usage among college students. The Internet Addiction Test (IAT) was developed in 1998 before the widespread use of smartphones. Researchers also developed a new scale based on current internet usage patterns.

“Internet use has changed radically over the last 18 years, through more people working online, media streaming, social media, etc. We were concerned that the IAT questionnaire may not have been picking up on problematic modern internet use, or showing up false positives for people who were simply using the internet rather than being over-reliant on it,” chief researcher Michael Van Ameringen said in a statement.

Researchers studied internet usage of 254 students and correlated the results with their general mental health. Based on their results in the IAT, 33 students suffered from internet addiction but based on the new scale, the number went up to 107. Scientists also administered self-reported tests to study how internet usage affects the students’ mental health. The tests focused on illnesses like depression and anxiety, impulsiveness, inattention and executive functioning, and Attention Deficit Hyperactivity Disorder (ADHD).

Researchers found that students who screened positive for internet addiction on both scales had more trouble in dealing with everyday activities. “Individuals with internet addiction also had significantly higher amounts of depression and anxiety symptoms, problems with planning and time management, greater levels of attentional impulsivity as well as ADHD symptoms,” Van Ameringen added.

He said the survey indicates that the prevalence of internet addiction might be grossly underestimated. The survey, however, does not prove if the mental health issues are a consequence of internet addiction.

“This may have practical medical implications. If you are trying to treat someone for an addiction when in fact they are anxious or depressed, then you may be going down the wrong route. We need to understand this more, so we need a bigger sample, drawn from a wider, more varied population,” Van Ameringen said.