The cost of mental illness to New Zealand's economy is 5 percent of gross domestic product, and skyrockets if drug abuse is included, a new report reveals.
Mentally-ill people have a mortality rate which is twice as high as the general population, with increased risk of death from cancer, cardiovascular disease and external causes such as suicide.
Those with psychotic disorders like schizophrenia have a mortality rate that is three times higher.
While the Te Pou - Equally Well coalition is addressing the issue, encouraging more services to bridge the gap between physical and mental health care could aid sufferers as well as the economy.
"It is well recognised that to win a war one must know the enemy," the Royal Australian & New Zealand College of Psychiatrists president Malcolm Hopwood wrote in the report.
"Recognising that people with serious mental illness almost always live with comorbid physical illnesses and their risk factors, and improving their care, is a complex challenge.
"But it cannot be more difficult than other issues once thought to be insurmountable," says Professor Hopwood.
The overall cost of the burden of disease to New Zealand adds up to $17 billion (7.2 percent of GDP) if opioid dependence is included within the scope, or $12b (5 percent of GDP) without.
Substance abuse and premature deaths are major contributors, with drug abuse doubling the economic impact of early mortality from $3.1b to $6.2b when included.
The situation is also concerning for Maori -- who already have reduced life expectancy when compared with non-Maori New Zealanders, Tu Te Akaaka Roa chair Dr Mark Lawrence says.
"The ugly truth is that it seems to be quietly accepted that there is a higher risk of premature death for people with mental illness due to physical illness or suicide," he says.
"This evidence demonstrates that there is a financial windfall waiting for the Government brave enough to make saving people's lives the priority."
Mental illness affects one in four people across New Zealand.
An estimated 105,350 people were suffering from a serious mental illness in 2014.