FRIDAY, April 22, 2016 (HealthDay News) -- The anti-smoking drugs Chantix (varenicline) and Wellbutrin (bupropion) don't appear to raise the risk of serious mental health disorders such as depression, anxiety and suicidal thoughts, a new study suggests.
"Clinical guidelines recommend that the most effective way to give up smoking is smoking cessation medication and counseling. However, smokers do not use these services enough, in part due to concerns that the medications may not be safe," said lead author Dr. Robert Anthenelli, professor of psychiatry at University of California, San Diego.
The new study, published April 22 in The Lancet, should help ease those concerns for patients, the researchers said.
The study was requested by the U.S. Food and Drug Administration due to concerns about the safety of the drugs used to help people quit smoking. Funding was provided by drug makers Pfizer (which makes Chantix) and GlaxoSmithKline (maker of Wellbutrin).
The research included more than 8,000 people between the ages of 18 and 75. They smoked an average of more than 10 cigarettes a day and wanted to quit smoking. Half had a previous or current psychiatric condition, such as a mood, anxiety, psychotic or borderline personality disorder, while about half of those participants were taking medications for their conditions.
The participants were randomly assigned to one of four possible groups: to take either Chantix or Wellbutrin, to use nicotine patches or to take a placebo.
They were assessed for moderate-to-severe mental health problems such as agitation, aggression, panic, anxiety, depression and suicidal thoughts during up to three months of treatment and at follow-up (up to six months).
Among those with no psychiatric disorders, there was no significant increase in the incidence of mental health problems in the four groups. While more mental health problems occurred among participants with psychiatric disorders, the rates were similar for all four groups, the study found.
The researchers also examined quit rates and found that varenicline was the most effective. At follow-up, overall quit rates were: 22 percent, Chantix; 16 percent, Wellbutrin; 16 percent, nicotine patches; and 9 percent, placebo.
Quit rates were slightly lower for those with a psychiatric disorder, the study said.
Anthenelli said the findings from this study and previous ones make it unlikely that these drugs increase the risk of moderate-to-severe mental health side effects in smokers without psychiatric disorders.
The study results "show that neuropsychiatric adverse events occurring during smoking cessation are independent of the medication used," addiction expert Laurie Zawertailo wrote in an accompanying editorial.
"Clinicians should be comfortable prescribing the smoking cessation medication they feel would be most effective for their patient and should not worry about a specific medication increasing the risk of neuropsychiatric side effects," said Zawertailo, an assistant professor in the department of Pharmacology and Toxicology at the University of Toronto.
She added that patients who are trying to quit need to know that severe changes in their mood can occur.
"Clinicians should monitor all of their patients, especially those with a current or past psychiatric illness, for these changes," Zawertailo said. "This monitoring could be added to the behavioral counseling that clinicians should be providing to patients who are trying to quit smoking."
Two experts in helping smokers quit said the findings are valuable for patients.
"In my experience there has been reluctance among many practitioners to prescribe varenicline and/or bupropion for their tobacco-dependent patients, due to concerns about potential neuropsychiatric adverse events," said Patricia Folan. She directs the Center for Tobacco Control at Northwell Health in Great Neck, N.Y.
She said many smokers also look for information on quit-smoking aids on the internet, and "frequently decide to avoid these medications because of the reported side effects -- resulting in their continued smoking.
"Demonstrating the safety and efficacy of these cessation treatment options for tobacco users will most likely lead to additional quit attempts and quit success," Folan believes.
Dr. Len Horovitz is a pulmonary specialist at Lenox Hill Hospital in New York City. He agreed that, based on the new findings, "medication-assisted smoking cessation is safe and freer from side effects than patients -- and doctors -- may fear."
The American Cancer Society offers a guide to quitting smoking.