The link between depression and smoking, long observed by health-care experts, is real and strong, a new government report shows.
People aged 20 and older with depression are twice as likely as others to be cigarette smokers, the researchers from the US Centres for Disease Control and Prevention found. And as the severity of depression increased, so did the number of smokers.
The magnitude of the link was surprising, said researcher Laura Pratt, an epidemiologist at the CDC's National Centre for Health Statistics, which published the findings April 14.
"The relationship between depression and smoking has been getting stronger over time," she said. Studies found only a small, insignificant link among Americans in 1952 and 1970, she said. But when Pratt and her co-researcher Debra Brody analysed information from 2005 to 2008 culled from the National Health and Nutrition Examination Survey, they found that:
About 43% of adults 20 and older who had depression smoked, compared with 22% of that age without depression.
Women with depression had similar smoking rates as men, although women without depression smoked less than men.
As depression worsened, the percentage of adults who were smokers increased.
Depressed smokers smoke more than smokers without depression.
Adults who are depressed and smoke are less likely to quit than are smokers who are not depressed.