More than 40 percent of U.S. adults who have depression are also smokers, meaning people need help with both if they want to quit, according to a U.S. government survey published on Wednesday.
The survey found more than half of middle-aged men with depression were also smokers, while half of women under age 40 who were depressed also smoked.
Patients with depression who want to kick the habit can be helped, but it is difficult, said Laura Pratt and Debra Brody of the National Center for Health Statistics, who conducted the study.
"The few studies that have examined ability to quit smoking in persons with depression have shown that with intensive treatment, persons with depression can quit smoking and remain abstinent," they wrote.
"These intensive cessation services often use treatments that are also used for depression, including cognitive-behavioral therapy or antidepressant medications."
Pratt and Brody used a national survey of 5,000 people to break out the percentage of smokers among people with depression.
They found 43 percent of adults over 20 with depression smoked, versus 22 percent without.
"Over one-half of men with depression aged 40-54 were current smokers compared with 26 percent of men without depression of the same age," they wrote.
"Among women aged 40-54, of those with depression, 43 percent were smokers compared with 22 percent of those without depression," they added. Fifty percent of depressed women aged 20 to 39 smoked.
Some antidepressants help smokers quit
Antidepressants used to help smokers quit include GlaxoSmithKline's Zyban, known generically as bupropion, and Pfizer's Chantix or varenicline.
Pfizer is fighting off lawsuits that allege the company did not warn quickly enough about the risks of attempted suicide with its drug, which now carries a strong "black box" warning, as do many other antidepressants.
Pratt and Brody also found that patients with depression are more likely to be heavy smokers, and the worse the depression, the more likely they are to smoke.
About 7 percent of U.S. adults had depression in the years 2005 through 2008, the researchers said.
Globally, tobacco kills about 5 million people a year, according to the World Health Organization and the U.S. Centers for Disease Control and Prevention.
"On average, smokers die 13 to 14 years earlier than nonsmokers," the CDC says. "Cigarette smoking is responsible for about one in five deaths annually, or about 443,000 deaths per year."