About half of smokers seeking treatment for smoking cessation have a history of depression. Compared with smokers who are not depressed, those who suffer from a major depressive disorder (MDD) have greater difficulty quitting.
In a Pfizer-sponsored clinical trial to assess the effect of varenicline (Chantix) on smoking cessation, as well as mood and anxiety levels in smokers with current or a history of depression, researchers concluded that the drug does help some of these patients to quit smoking without worsening symptoms of depression or anxiety.
The study was led by Robert Anthenelli, MD, associate chief of staff for mental health at VA San Diego Healthcare System and professor of psychiatry at UC San Diego School of Medicine, where he directs the Pacific Treatment and Research Center. It will be published September 17 in the journal Annals of Internal Medicine.
"Depression and smoking are among the leading causes of disability and death in the world, yet studies testing smoking cessation drugs generally exclude participants who are taking antidepressants, and relapse rates are high among those who do manage to quit," said Anthenelli. "To our knowledge, this was the first randomized, controlled study of the prescription smoking-cessation drug, varenicline, which we found to help patients with depression quit smoking, without worsening their depressive symptoms."
The study looked at 525 adult smokers with stable current or past major depression, from 38 centers in eight countries. The study participants smoked at least 10 cigarettes a day, and were motivated to quit smoking. They took either varenicline or a placebo twice daily for 12 weeks; after treatment ended, researchers followed them for an additional 40 weeks.
During the last four weeks of treatment, 36 percent of those treated with varenicline quit smoking, compared with 16 percent of the placebo group. At the end of the 40-week follow up, 20 percent of the varenicline group continued to abstain from smoking, compared to10 percent of the placebo group. No differences were reported between the groups in mood, anxiety or thoughts about suicide, according to the researchers.
"While this study didn't look at smokers with untreated depression, this drug may improve efforts by depressed smokers to quit and to maintain abstinence from tobacco use," Anthenelli said.