Mental disorders are estimated to cost the global community nearly $2.5 trillion each year — and those costs are increasing.

Unlike costly physical illnesses like cancer, where expenses are largely hospital-based, mental health costs are often indirect, such as not being able to work.

Only 40 percent of adults who have a mental illness reported receiving any sort of service for their mental illness in the prior 12 months, according to Judith Bass, a professor at Johns Hopkins Bloomberg School of Public Health. This number drops to below 15 percent in low- and middle-income countries.

“With mental and behavioral health, the lack of services means the future cost implications are even higher because people aren’t even getting treatment,” Bass said.

Treatment options may be limited due to a shortage of trained mental health workers or the stigma mental illness often carries.

“The stigma of mental illness is probably as big a problem as mental illness itself,” said Patrick Corrigan, a professor of psychology at the Illinois Institute of Technology. “And despite how educated we are, there’s pretty good evidence it’s getting worse.”

Corrigan said another reason why mental illness can be so costly is because it often affects younger people in their prime working years.