Varenicline may help some patients with depression quit smoking

AnthenelliAbout 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, according to a study published September 17 in the Annals of Internal Medicine.

A Pfizer-sponsored clinical trial assessed the effect of varenicline (Chantix, Pfizer) on smoking cessation, as well as mood and anxiety levels in smokers with current or a history of 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 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.

The study looked at 525 adult smokers with stable current or past major depression, from 38 centers in 8 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 4 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 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,” Dr Anthenelli said.

There are 3 take-away messages, according to Dr Anthenelli.

“The first is that the study demonstrates that varenicline helps smokers with stable depression quit smoking, and since nearly 1 out of 2 smokers seeking cessation treatment have current or past major depression, this represents a large segment of smokers who might derive benefit,” he told Formulary. “[Secondly] our results are reassuring from a neuropsychiatric safety perspective, because varenicline did not worsen overall measures of depression, anxiety, or suicidal thinking or behavior. [Finally] 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.”

Dr 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.