Whether mood can have lasting effects on human health is one of the most controversial questions in modern medicine. In a article in the November issue of the American Journal of Epidemiology, Johns Hopkins University researchers present evidence that depressed people who smoke run a substantially higher risk of cancer than non-depressed smokers.
In a 12-year study of 2,264 people in Washington County, Md., researchers led by Hopkins epidemiologist George Comstock found that depressed smokers had between 2.6 and 4.5 times the risk of cancer found in nonsmokers who were not depressed. Smokers who did not suffer from depression had cancer rates that were only 1.25 to 1.6 times as high as those found in the nonsmokers.
The study did not find depression alone heightened cancer risk, but that it seemed to become dangerous only in combination with smoking.
"The principal purpose of this study is not to convince depressed people to quit smoking," said Comstock. "There's enough evidence for that already. The important thing is to establish whether or not the mind can affect the body in ways that can lead to an increased risk of things like cancer. . . . This is tantalizing evidence that there is something to this."