Researchers at University of California San Diego School of Medicine have identified a clear group of characteristics that predict heightened risk for experiencing increased anxiety or worsening of mood that interferes with daily activities when using a smoking cessation drug. Results are published in the February 27, 2019 online edition of the Journal of General Internal Medicine.

"This is the first time that a large scale multinational study has carefully examined psychiatric events among smokers with and without , comparing risks across all three frontline medications," said first author Robert Anthenelli, MD, professor of psychiatry and director of the Pacific Treatment and Research Center at UC San Diego School of Medicine. "By identifying the baseline characteristics that predict moderate-to-severe adverse events, we can better treat all patients."

"We learned that there are three predictors of clinically significant psychiatric adverse events in both smokers with and without : existing anxiety, a of suicidal ideation or behavior and being of white race," said Anthenelli. "In participants with histories of mental health issues, predictors included being young, female, a long-term smoker and a history of co-occurring psychiatric and substance abuse disorders."

The findings represent a secondary analysis of the 2016 EAGLES study, which found that 2 percent of participants with no prior history of mental experienced a moderate-to-severe psychiatric event while using a cessation aid. In patients with a prior history of mental illness, 6 percent had such adverse events.

"The good news is that the vast majority of people do not have adverse psychiatric events when taking the most prescribed smoking cessation drugs," said Anthenelli. "These medicines are effective aids to quit smoking. However, like all drugs, these medications should be monitored, especially in patients who have a diagnosis of mental illness."

Eligible participants for the original placebo-controlled study were men and women aged 18 to 75 years who smoked an average of more than 10 cigarettes per day and who were motivated to stop smoking. Tested therapies included a nicotine patch, bupropion and varenicline.

"People with mental illness are a neglected subpopulation of smokers," said Anthenelli. "They smoke at rates two to four times higher than the general population and consume nearly one out of every two to three cigarettes sold in the U.S. and U.K.

"These individuals have a harder time quitting smoking and are disproportionately affected by tobacco-related diseases and premature death. Just because they have mental illness, however, does not mean they should not consider a as the risk of disease from long-term smoking is much greater."