Smokers who kick the habit appear to benefit from an improved mood, according to a new review of past studies.
On average, quitting smoking was associated with improvements in mental health similar to taking an antidepressant drug, a team of UK researchers found.
"The main message is that when people stop smoking, they feel better than they did when they were smoking," Dr. Paul Aveyard, one of the review's authors, told Reuters Health.
"People who quit smoking may feel grumpy, irritable and bad - those feelings are similar to feelings of stress and people conflate the two," Aveyard, from the University of Oxford, said.
"For clinicians like myself, when we see people who smoke who also have mental health difficulties, there's often a feeling that we are depriving them of a way to deal with the stress," he said. "But in fact we are helping these people to get better."
It is widely known that quitting smoking has saved lives. But it's nearly impossible to prove that smoking causes specific health problems, or that quitting prevents them, because of other differences that exist between smokers and non-smokers that could impact health and well-being.
With that in mind, "the claim of this paper that quitting is as good as drugs needs more research," Dr. Prabhat Jha, of the University of Toronto Centre for Global Health Research in Canada, wrote in an email to Reuters Health. Jha was not part of the new analysis.
For their review, the researchers examined data from 26 studies of smoking cessation. Some studies included smokers in the general public and others focused on people in psychiatric hospitals. Participants smoked an average of 20 cigarettes per day initially.
All of the studies assessed participants' mental health before quitting smoking and about six months later, on average.
Compared to people who continued to smoke, the studies showed drops in anxiety, depression and stress and improvements in psychological quality of life among quitters.
Other explanations related to mood improvements among quitters need to be considered, the researchers write in the British medical journal BMJ. For example, it's possible that life events improved people's mood, leading them to quit smoking.
Still, there is "an entrenched belief in our culture that smoking ‘calms the nerves' and can help alleviate stressful situations," psychiatry researcher Benjamin Le Cook of the Cambridge Health Alliance in Somerville, Massachusetts told Reuters Health in an email. He said this message has met little resistance from public health, mental health and medical communities so far.
The current review serves as a reminder that tobacco withdrawal symptoms like anxiety can easily be confused with mental health problems, said Brian Hitsman of the Northwestern University Feinberg School of Medicine in Chicago. Both he and Le Cook were not involved in the review.
"It's possible that the emotional withdrawal symptoms are interpreted as an acute worsening of psychiatric symptoms," Hitsman wrote in an email to Reuters Health.
Aveyard and his colleagues conclude that people who smoke "can be reassured" that quitting is tied to improved mental health.
"It's getting harder and harder to find any real benefits of smoking," Jha said.