Ever take a day off from work and tell your boss you needed a sick day, when what you really needed was a mental health day?

Deborah Jacobs, an HR professional who sits on the advisory council of the Disability Management Employer Coalition, says you’re not alone.

“We had a lot of employees that have physical disabilities, but we find out as we’re looking into their cases that they also have a mental behavioral health issue going on at the same time,” she says.

“Behavioral health” – essentially a mash-up of mental and physical health – is getting more attention in the workplace, Jacobs says.

A report from Employers Health says that workers miss more days of work and are less productive due to mental illness than chronic conditions such as high blood pressure and even back pain.

Pamela Warren is doctor of psychology and a University of Illinois faculty member. She says depression, for instance, may cause physical ailments that can result in disability or employee absence.

“Over time and actually pretty early in my practice, what I started seeing were individuals who they focused on the reported work issues, but found they couldn’t or wouldn’t go to work,” she says.

According to some estimates, this is costing employers upwards of $100 billion dollars.