People with mental health disorders have a death rate that is more than twice as high as those without mental illness, according to a study published this morning.

Researchers found that those with mental health disorders died a median of 10 years sooner, according to the study, published online in JAMA Psychiatry.

“We estimate that 14.3 percent of deaths worldwide, or approximately 8 million deaths each year, are attributable to mental disorders,” the scientists wrote.

The link between mental illness and death is complicated because most people with those disorders do not die of them. People with mental health disorders are, however, more likely to have other risk factors that can affect mortality, such as other health problems or a history of substance abuse.

The researchers hope that understanding that those with mental illness have increased risk of death will lead to better treatment approaches.

The Emory University researchers reviewed medical literature to examine mortality among people with mental health disorders.

The public health scientists analyzed 148 studies and found that people with mental illness have a risk of dying that is 2.22 times higher than those without such conditions. Among people with mental health disorders, 67.3 percent died of natural causes and 17.5 percent of unnatural causes. Other or unknown causes accounted for the remainder of the deaths.

“People with mental disorders experience a high burden of mortality at the individual and population levels,” the study concludes. “Reduction of this burden will require a focus on less prevalent but more severe diagnoses and more common mental disorders. Likewise, efforts must be made to prevent and manage co-morbid medical conditions and reduce the occurrence of unnatural deaths in this vulnerable population.”