Adults who suffer from depression are twice as likely to smoke and also smoke more heavily than adults who are not depressed, a study released Wednesday shows.
Forty-three percent of all adults aged 20 and older who suffer from depression smoked cigarettes, compared with 22 percent of adults who were not depressed, data compiled by the US National Center for Health Statistics, which is part of the Centers for Disease Control and Prevention show.
The phenomenon was the most marked among men between the ages of 40 and 54 and women between the ages of 20 and 39.
More than half of men with depression, aged 40-54, were smokers compared to less than a quarter of men in the same age group who were not depressed, while half of women aged 20-39 who suffered depression smoked compared with 21 percent of women who were not depressed.
Nearly three in 10 adults with depression smoked more than a pack of cigarettes per day, which was almost twice the rate for adult smokers who were not depressed.
Even adults with mild depressive symptoms were more likely to smoke than adults with no symptoms at all of the chronic illness.
Symptoms of depression can be physical or psychological and include changes in sleeping and eating patterns, reduced sex drive, excessive fatigue or feelings of worthlessness or guilt.
Smokers who were depressed were more likely than non-depressed smokers to light up within five minutes of waking up: 51 percent of depressed smokers did so compared to three in 10 smokers who were not depressed.
Smokers with depression also had more difficulty kicking the habit.
Around seven percent of US adults aged 20 and over suffered from depression in 2005-2008, the study said.
The percentage of US adults who smoke cigarettes has fallen by half since the US Surgeon General issued the first report on smoking and health in 1964, but around one in five US adults still smoke, the study says.
Explore further: Dutch doctors withhold/withdraw treatment in many elderly patients