People with serious mental illness – such as schizophrenia, bipolar disorder and disabling depression – are 2.6 times more likely to develop cancer than the general population, a new study by Johns Hopkins suggests. The study’s findings raise questions about whether patients with serious mental illness are receiving appropriate cancer screenings and preventive care related to risk factors, such as smoking.
The increased risk is definitely there, but we’re not entirely sure why, says the study leader, an associate professor of medicine and psychiatry at the Johns Hopkins University School of Medicine. “Are these people getting screened? Are they being treated? Something’s going on.”
In a separate study, published online last month in the journal Injury Prevention, it was found that people with serious mental illness were nearly twice as likely to end up in a hospital’s emergency room or inpatient department suffering from an injury than the general population and about 4.5 times more likely to die from their injuries.
Roughly 5 percent of Americans have a serious mental illness, and this group is known to be two to three times more likely to die prematurely than those without disabling psychiatric problems. A small proportion of the higher risk, she says, can be attributed to the higher risks of suicide and homicide victimization in this population, but those factors do not account for most of the disparity. The top causes of death are cardiovascular disease and cancer, the same top causes of death for those without serious mental illness. Speculation is that this population is “falling through the cracks.”
In the first study, data from 3,317 people with schizophrenia and bipolar disorder were evaluated, determining whether they developed cancer between 1994 and 2004 and what type of cancer they had. It was found that patients with schizophrenia, when compared to the general population, were more than 4.5 times more likely to develop lung cancer, 3.5 times more likely to develop colorectal cancer and nearly three times more likely to develop breast cancer. People with bipolar disorder experienced similarly high risk for lung, colorectal and breast cancer.
One reason for the elevated risk of lung cancer could be smoking, which is more prevalent in people with serious mental illnesses. The professor also speculates that the breast cancer risk could be related to the fact that women with schizophrenia and bipolar disorder are less likely to have children, and childbearing is believed to reduce breast cancer risk. The colorectal cancer risk, she says, could be related to lifestyle issues, such as smoking, lack of physical activity and a diet lacking fruits and vegetables.
More study is needed on extent to which this population receives appropriate cancer screening and treatment. Mental health providers and primary care physicians must work together to promote screening as well as to reduce risk factors such as smoking among this group.