NEW YORK - People with schizophrenia and other psychotic disorders are more likely to die of heart disease than mentally healthy individuals, a study in US veterans indicates.

While the fact that people with psychosis were more likely to smoke and be inactive accounted for much of the difference, it didn't explain all of it; it's likely that the isolating, debilitating nature of the mental illness itself is also a factor, Dr. Amy M. Kilbourne of the VA Ann Arbor Health System in Michigan, the lead author of the study, told Reuters Health.

People with serious mental illness die decades earlier than their mentally healthy peers, Kilbourne and her team note in their report. To understand the role of heart disease in shortening the lifespan of mentally ill individuals, they looked at nearly 150,000 vets who had completed a 1999 survey.

Just 11 percent had never been diagnosed with a mental disorder, while 15.5 percent had schizophrenia, 10 percent had bipolar disorder, 5 percent had psychotic symptoms but hadn't been diagnosed with schizophrenia, 24 percent had major depression, and 34.5 percent had other types of depression.

Within 8 years, 8 percent of the study participants had died of heart disease. Individuals with psychosis were nearly twice as likely to die of heart disease during follow-up compared to those who'd never been diagnosed with a mental disorder.

People with schizophrenia, depression and bipolar disorder also were at increased risk of dying from heart disease, but for individuals with depression or bipolar illness, behavioral factors such as smoking and lack of physical activity accounted for all of the excess risk.

But even after these factors were taken into account, people with schizophrenia were still 17 percent more likely to die of heart disease, while people with other psychotic disorders were at 30 percent greater risk.

The individuals who had psychotic symptoms -- indicating a loss of touch with reality -- but who didn't have schizophrenia may have been suffering from dementia or had experienced episodes of delusions or hallucinations for other reasons, Kilbourne noted.

"Just having an unstable life ... because of psychotic symptoms really gets in the way of people living a full life," the researcher said. "Having symptoms of psychosis really puts people in a vulnerable situation. It's really difficult for them to navigate a health care system, to talk to a health care provider about what their needs are, to take care of themselves."

To help people with serious mental illness, Kilbourne added, it's important to offer them a "medical home," a place where all their health care needs can be met. This care must address the whole person, she said, not just his or her mental problems, and should also include health behavior change education. The VA is currently implementing all of these approaches in caring for vets with mental illness, the researcher said.

In a Health Behavior News Service release accompanying the study, Dr. Eric Goplerud, director of the Center for Integrated Behavioral Health Policy in Washington, said the issue of cardiovascular disease in this population is "huge."

"As we look at national health reform, it is absolutely critical that people with mental illness and addictions be included -- they are dying of preventable medical conditions," Goplerud said.