One-in-five American college students report suffering from anxiety disorders in what researchers are calling an “anxiety epidemic”.

Preliminary findings presented by the Berkeley Institute for the Future of Young Americans suggest that the rate of students with anxiety disorders has doubled since 2008 and can be linked to increased time on digital devices, social media in particular, and financial stress.

“This is a big, complicated societal problem,” lead researcher Richard Scheffler told IFLScience in an interview. “We do know that when rates double over an eight-year period, from 10 percent to 20 percent, that can be called an epidemic.”

Even so, that number is likely an underestimate given the researchers only looked at those diagnosed or in treatment for anxiety. Many others may not have the means to seek help or opt out of doing so because of the stigmas associated with mental health disorders.

To look at the levels of anxiety amongst college students, researchers inspected nine years of data from the National College Health Assessment survey and the National Longitudinal Survey of Youth – both surveys that look at students’ well-being. The team also interviewed 30 UC Berkeley students who reported having anxiety. They found that students who come from families that have difficulty paying their bills were almost three times more likely to have anxiety. Perhaps more alarming, those who spent 20 hours of leisure time on digital devices for social media purposes were 53 percent more likely to have anxiety than those who spent less than five hours each week.

“College students, in particular, look at their peers [online] and see what they’re doing,” said Scheffler. “People tend to post things on social media that makes them look good, so whoever is looking gets a biased view of what others are doing and think they’re doing less well when the reality is that these people are maybe exaggerating and, for the most part, we don’t hear from people who are not doing well because of the stigma attached.”

Scheffler notes that there are a lot of factors and while correlation doesn’t mean causation, his research suggests that screen time use is strongly correlated with the diagnoses or treatment of anxiety disorders. Either way, the effects of these levels of anxiety extend beyond the college years.

While most college students suffer from “normal” levels of anxiety associated with transitioning to adulthood and the pressures of success, Scheffler notes that his team is seeing “another level” of anxiety that is costing an estimated $3 billion a year in associated medical costs. A long-term analysis suggests that those who reported anxiety in college earn around 11 percent less than their peers, are three times as likely to abuse drugs and alcohol, and are resulting in an rising number of emergency room visits – and that trend is increasing.

“What we’re seeing each year is that the level [of anxiety] these students start off at is higher than it was the year before,” explained Scheffler, adding that awareness campaigns should be addressed at campuses around the world in order to help those who may be suffering from anxiety and panic disorders.

Full results from the study are set to be published later this summer.