"A sad soul can kill you quicker, far quicker, than a germ," John Steinbeck once wrote. Now we are closer to understanding why.
A disease like cancer can be a mortal battle, often fraught with overwhelming stress. Given that stress management can be difficult even under ordinary circumstances, elevated feelings of anxiety and depression in cancer patients are certainly understandable.
Yet, several recent studies underscore how critically important it is for those fighting illness to learn how to combat stress.
A team of researchers led by Lorenzo Cohen, professor of general oncology and director of the Integrative Medicine Program at The University of Texas MD Anderson Cancer Center, found that symptoms of depression among a group of patients with late-stage renal cell carcinoma were associated with an increased risk of death. The study was published in the journal PLOS ONE in August.
The chief suspects in Cohen's study: cortisol -- also known as the "stress hormone" -- and inflammatory pathways.
"This study is the next step in the process of understanding that emotional factors have an impact on biology, which can, in turn, influence outcomes in cancer," says Cohen.
Cortisol is the hormone produced by the adrenal gland in response to stress. It helps regulate the inflammatory response in the body.
According to Cohen, under normal circumstances cortisol levels should be high in the morning and drop throughout the course of the day. But among patients experiencing chronic stress or depressive symptoms, cortisol levels can remain sustained throughout the day, with less of a decrease in the evening.
In the study, those patients with sustained cortisol levels throughout the day had an increased risk of mortality. Through gene profile analyses of patients, the researchers documented that the association between patient psychological condition and survival time may stem from a dysregulation in inflammatory biology.
Two other studies on how stress influences other illnesses shed further light on this process.