"Everyone knows people with depression are more likely to smoke," Pratt said, but what surprised her, she said, was the extent to which that was found true in the study.
For instance, among women aged 20 to 39 they found that 50 percent of those with depression smoke, whereas just 21 percent of those without depression do.
Even adults with mild depressive symptoms -- those who wouldn't qualify for a diagnosis of clinical depression -- were more likely to smoke than were people with no symptoms of depression, the researchers found.
Exactly why depressed people tend to smoke more was beyond the scope of the study, Pratt said, but some research has suggested they might be self-medicating, with the cigarettes somehow acting as a calming or relaxing mechanism.
Stanton A. Glantz, director of the Center for Tobacco Control Research and Education at the University of California, San Francisco, said the findings were not surprising.
And he agrees that depressed people who smoke may be self-medicating. Part of the problem, he said, is that mental health professionals have been slow to deal with the tobacco issue.
"There's a myth that somehow if you deal with it, [by encouraging them to quit smoking,] it makes it harder to deal with underlying mental illness," Glantz said. "Just the opposite is true."
The U.S. National Institute of Mental Health has more on depression.
SOURCES: Laura A. Pratt, Ph.D., epidemiologist, Office of Analysis and Epidemiology, National Center for Health Statistics, U.S. Centers for Disease Control and Prevention, Hyattsville, Md.; Stanton A. Glantz, Ph.D., pr
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