Varenicline may be a helpful smoking-cessation aid to stable depressed patients already receiving antidepressants or anti-anxiety medications, and its use does not appear to worsen moods, thoughts, or emotional states.
About half of smokers seeking treatment for smoking cessation have a history of depression. According to a study published September 17 in the Annals of Internal Medicine, it is harder for smokers who suffer from major depressive disorder (MDD) to quit smoking than it is for smokers who are not depressed.
The Pfizer-sponsored clinical trial assessed the effect of varenicline (Chantix, Pfizer) on smoking cessation, as well as on mood and anxiety levels in smokers with present or past depression or anxiety.
“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 study leader Robert Anthenelli, MD, associate chief of staff for mental health at the Veterans Affairs San Diego Healthcare System and professor of psychiatry at the University of California San Diego School of Medicine, where he directs the Pacific Treatment and Research Center.
The study looked at 525 adult smokers, with stable current or past major depression, from 38 centers in eight countries. 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, close to 36% of those treated with varenicline quit smoking, compared with 16% of the placebo group. At the end of the 40-week follow-up, 20% of the varenicline group continued to abstain from smoking, compared to 10% of the placebo group. No differences were reported between the groups in mood, anxiety, or thoughts of suicide, the researchers reported.
“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.
He noted three study conclusions. “The first is that the study demonstrates that varenicline helps smokers with stable depression quit smoking, and since nearly one out of two smokers seeking cessation treatment have current or past major depression, this represents a large segment of smokers who might derive benefit,” he said.
Second, he continued, “Our results are reassuring from a neuropsychiatric safety perspective, because varenicline did not worsen overall measures of depression, anxiety, or suicidal thinking or behavior."
And third, "To our knowledge, this is the first randomized controlled trial conducted in smokers with stable depression where roughly three-fourths of the subjects were being treated with commonly prescribed antidepressant and anti-anxiety medications. Thus, we think our findings are relevant to a clinical population that physicians are likely to encounter in their practice.”
Anthenelli is a scientific advisor to Pfizer, Inc. He receives no personal income and his services have been contracted by The Regents to Pfizer. As a result of this contractual arrangement, Dr. Anthenelli receives funding to support research and other university activities