The number of people living with mental illness worldwide is underestimated by more than a third, according to researchers at Harvard University and King's College London, who say mental illness accounts for 32 percent of all disability worldwide.
Previously, mental illness was thought to be responsible for 21 percent of global disability.
Researchers say people with other health problems — such as heart disease, pain syndromes, neurological problems and HIV — often suffer from psychiatric disorders that go unrecognized by the medical profession.
Clinical depression often goes along with chronic illness but is rarely reported and treated, according to the authors, whose work is published in the journal The Lancet Psychiatry.
Cost of stigma
Those psychiatric disorders exact a high human cost, said Daniel Vigo, a psychiatrist and fellow at Harvard's School of Public Health in Boston.
“People with mental illness die before a heavy smoker, just to have a perspective on how serious this is," Vigo said.
Part of the problem, he said, is the stigma that accompanies mental illness. People with psychiatric disorders are more likely to avoid doctors and treatment than people who are physically ill.
He said the percentage of people who are being treated for mental disorders, about 8 percent of the U.S. population, is only the beginning.
Vigo and his colleagues are calling for greater recognition of the problem by the global community, and for treatment for psychiatric conditions to be offered at the primary care level where many people with other health problems are seen.
"Mental health services need to evolve and not be considered a separate issue anymore,” he said. “And there are a number of evidence-based interventions that are being piloted or applied on a much larger scale in both developed and developing countries that show the way this can be done."
Treatments that can be offered through primary care include medication and therapy, but recognizing a problem exists is the first step, according to Vigo.
In April, a mental health summit will take place in Washington in conjunction with the annual meeting of the World Bank.