JACKSONVILLE, Fla. -

As kids head back to school we're learning there's a possible connection between what happens in the classroom and childhood mental health disabilities.

Those disabilities like ADHD and autism are on the rise in the United States.

Researchers said the increase may be because people are more aware of the issues. They also said stress may be a big factor, and that underprivileged kids may be more likely to have those disabilities.

A study published in this week's online issue of Pediatrics said the number of children with disabilities rose 16-percent over a 10-year period.

David Chesire is an assistant professor of licensed psychology at UF Health.

"Part of it has to do with, we do a better part of recognizing child illness, where it used to be ignored... Part of it is there's probably an overall actual increase in stress out there," said Chesire.

Chesire said more homework and kids getting overwhelmed could be to blame.

"The more stress you're under, the more likely you're to lose the ability to cope with that stress that causes mental health issues," said Chesire.

Researchers found that physical disability health issues were down 12-percent and that disabilities with mental and neurological health went up 21-percent.

Underprivileged kids had the highest rates of disabilities overall, but researchers found children living in more affluent homes reported the largest increase in disabilities; an increase of more than 28-percent.

"I think it goes back to stress. Poorer families are more likely to have external stress. They may not be able to make ends meet or they may not be able to go out and have as much fun. More affluent families are going to have stressers too. They just may be able to go out and get outside influences to combat what the stress the child is dealing with," said Chesire.

Researchers said the increase among more affluent families could be because those families are more likely to seek help from a doctor.

Another report from the CDC this year reports 1 in 68 children in the United States has an autism spectrum disorder.

Chesire said it's important to catch the warning signs early and to get help as soon as possible.

Those signs include a child who is struggling or who simply can't get out of bed.