Depression, anxiety disorders and substance abuse, the three most common mental health conditions, cost Australia about $12.8 billion a year, according to a study funded by Medibank Better Health Foundation.

The sum, which includes $11.8 billion in lost productivity, underscores the urgent need for greater resources to support provision of mental health services, researchers say.

Additional costs to governments include $1.23 billion in forgone income taxes and $12.9 billion in welfare benefits.

“Mental health has been a key health focus in Australia in recent years, but to learn the impact is at least $12.8 billion is a call to do more,” Medibank Better Health Foundation Chairman Linda Swan said.

“The broad-ranging effects for those living with depression, anxiety and substance use can be devastating and we encourage more Australians to seek help from their GP if they don’t know where to start.”

Deakin University, which conducted the research, analysed data from the most recent National Survey of Mental Health and Wellbeing.

About 18.5% of Australians suffer the most common mental health conditions.