Study Raises Questions About Link Between Chantix and Depression, Suicide

For individuals with a history of depression treatment, the smoking cessation drug Chantix does not appear to make things any worse, with new research indicating that such users may not face an increased risk of worsened depression or suicidal thoughts, which have been potential side effects of Chantix reported by many former users.  

In a study published this week in the Annals of Internal Medicine, researchers from the Department of Veteran Affairs and the University of California found that smokers suffering from depression were able to take Chantix and quit smoking without increasing their depression. The study sought to answer questions which critics say Pfizer ignored during Chantix clinical trial by not testing the drug on people with depression before it hit the market.

The study looked at 525 smokers who had suffered major depression recently or in the past. They found that smokers who used Chantix quit at a higher rate than those given a placebo and had no worsening of depression or anxiety problems. The study did not look at those being treated with antidepressants and did not measure the Chantix side effects on smokers with no history of suicidal tendencies or depression.

Chantix (varenicline) is a Pfizer drug designed to help smokers quit. The drug works by reducing the positive feelings that come from cigarettes, blocking the receptors in the brain commonly stimulated by nicotine. However, a few years after the drug was introduced and heralded as a potential blockbuster medication in 2006, reports began to surface of users committing suicide or engaging in sudden, unusual behavior.

In June 2009, the FDA added a “black box” warning about the risk of psychological problems with Chantix, and Pfizer was ordered to conduct additional clinical trials to provide more data on how often neuropsychiatric symptoms and suicide with Chantix occur and what conditions cause them.

Thousands of users sued Pfizer, saying they had suffered violent behavior, aggression, suicidal tendencies or had even attempted suicide. A number of murders, deaths and suicides were blamed on the drug, which allegedly can cause nightmares so vivid and horrifying that the phrase “Chantix nightmare” has become a cultural reference.

In the federal court system, the Chantix litigation was consolidated as part of an MDL, or multidistrict litigation, which was centralized before U.S. District Judge Inge Johnson in the Northern District of Alabama. While a total of more than 3,000 lawsuits have been part of the Chantix MDL at one time, no case ever reached trial.

In March 2013, Pfizer announced that Chantix settlement agreements had been reached in a vast majority of the more than 2,500 cases filed nationwide on behalf of users who committed suicide, attempted suicide or suffered other unusually aggressive behavior after using the prescription medication to help them stop smoking.