The health toll of physical and mental illness is more than the sum of its parts.

A study of more than five million Canadians has found that having both physical and mental illness increases emergency department visits beyond what would be expected from simply tallying the health burden of each.

“When both are present, the sum of their impacts is greater than its parts,” says the study’s lead author Marc Simard, a biostatistician at the Institut National de Santé Publique du Québec.

The researchers looked at hospital patient diagnoses between 2012 and 2016, taken from a disease surveillance database that covers 98% of adults in Quebec, which has free, universal-access healthcare.

Armed with the information, they set about building a picture of how a mounting toll of physical and mental illness affects the likelihood people will make frequent visits to the emergency department, defined as three or more trips per year.

Read the full article in Cosmos magazine here