Kicking the habit: Study suggests that quitting smoking improves mood

Based on their results, the authors of the article published online Nov. 24 in the journal Nicotine & Tobacco Research recommend that smokers embrace quitting as a step toward improving mental as well as physical health, said Christopher Kahler, corresponding author and research professor of community health at the Warren Alpert Medical School of Brown University. Quitting is not, as some smokers may fear, a grim psychological sacrifice to be made for the sake of longevity.

"The assumption has often been that people might smoke because it has antidepressant properties and that if they quit it might unmask a depressive episode," said Kahler. "What's surprising is that at the time when you measure smokers' mood, even if they've only succeeded for a little while, they are already reporting less symptoms of depression."

Moving mood

Kahler and colleagues from Brown, The Miriam Hospital, and the University of Southern California studied a group of 236 men and women seeking to quit smoking, who also happened to be heavy social drinkers. They received nicotine patches and counseling on quitting and then agreed to a quit date; some also were given specific advice to reduce drinking. Participants took a standardized test of symptoms of depression a week before the quit date and then two, eight, 16, and 28 weeks after that date.

All but 29 participants exhibited one of four different quitting behaviors: 99 subjects never abstained; 44 were only abstinent at the two-week assessment; 33 managed to remain smoke-free at the two- and eight-week checkups; 33 managed to stay off cigarettes for the entire study length.

The most illustrative -- and somewhat tragic -- subjects were the ones who only quit temporarily. Their moods were clearly brightest at the checkups when they were abstinent. After going back to smoking, their mood darkened, in some cases to higher levels of sadness than before. The strong correlation in time between increased happiness and abstinence is a tell-tale sign that the two go hand-in-hand, said Kahler, who is based at Brown's Center for Alcohol and Addiction Studies (CAAS).

Subjects who never quit remained the unhappiest of all throughout the study. The ones who quit and stuck with abstinence were the happiest to begin with and remained at the same strong level of happiness throughout.

Kahler said he is confident that the results can be generalized to most people, even though the smokers in this study also drank at relatively high levels. One reason is that the results correlate well with a study he did in 2002 of smokers who all had had past episodes of depression but who did not necessarily drink. Another is that the changes in happiness measured in this study did not correlate in time with a reduction in drinking, only with a reduction -- and resumption -- of smoking.

Looking at the data, Kahler said, it is difficult to believe that smoking serves as an effective way to medicate negative feelings and depression, even if some people report using tobacco for that reason. In fact, he said, the opposite seems more likely -- that quitting smoking eases depressive symptoms.

"If they quit smoking their depressive symptoms go down and if they relapse, their mood goes back to where they were," he said. "An effective antidepressant should look like that."

In addition to Kahler, other authors on the study were Nichea Spillane of Brown's CAAS, Andrew Busch of the Centers for Behavioral and Preventive Medicine at The Miriam Hospital and Brown, and Adam Leventhal of the Keck School of Medicine at USC. The National Institute on Drug Abuse funded the study.