Depression is on the upswing — and America’s youth is feeling it the hardest.

The mental disorder’s prevalence rose significantly in the United States from 2005 to 2015, with a jump from 6.6% to 7.3%, according to a recent study published in the journal Psychological Medicine. Depression among youths aged 12 to 17 increased at a significantly higher rate (8.7% to 12.7%) than it did for any other age group.

“Depression appears to be increasing among Americans overall, and especially among youth,” lead study author Renee Goodwin, a professor at Columbia University’s Mailman School of Public Health, said in a statement. “Because depression impacts a significant percentage of the U.S. population and has serious individual and societal consequences, it is important to understand whether and how the prevalence of depression has changed over time so that trends can inform public health and outreach efforts.”

Also read: People are afraid to talk about mental health at work, but here’s how to do it

The study found significant increases in depression for both the youngest (12 to 17 and 18 to 25 years old) and oldest (50 and up) groups, as well as among men, women, non-Hispanic white people, the highest education and income groups, and the lowest income group. Though depression prevalence for both men and women rose over the timespan studied, there were no significant gender-based differences in the rate of increase.

The researchers drew data from the annual National Survey on Drug Use and Health, analyzing a total sample of 607,520 people aged 12 and up. These findings, the study authors suggest, can help steer public health initiatives and resources toward the groups whose depression prevalence increased most over time.

“Despite this trend, recent data suggest that treatment for depression has not increased, and a growing number of Americans, especially socioeconomically vulnerable individuals and young persons, are suffering from untreated depression,” Goodwin added. “Depression that goes untreated is the strongest risk factor for suicide behavior and recent studies show that suicide attempts have increased in recent years, especially among young women.”

Also read: Hey, new dads — this may be why you’re suffering from postpartum depression

Depression isn’t just emotionally, mentally and physically taxing: The economic cost of U.S. adults with major depressive disorder was $210.5 billion in 2010, according to a 2015 study, with 50% coming from workplace costs like productivity dips and absenteeism, 45% from direct medical and prescription drug costs and 5% from suicide-related costs.