Giving up the death sticks is linked to mental health improvements such as reduced anxiety, depression and stress, according to a systematic review of 26 studies. The effect of quitting seems to equal or exceed that of antidepressants used to treat mood and anxiety disorders.
Smokers smoke for all sorts of reasons—posturing, peer pressure, lessening stress, alleviating anxiety and calming their mood. Some evolutionary biologists even think people smoke as a risky, costly way to signal their quality as potential mates—laughing in the face of barriers to survival and reproduction such as cancer or impotence. (Though others found that these health risks are, as expected, unattractive.)
The review study, published last week in the BMJ, challenges the idea that smoking benefits your mental health. By analysing the results across studies, the researchers found that stubbing out the cigarettes is associated with lowered depression, anxiety and stress as well as improvements in psychological quality of life and positive affect (this is, emotions and moods).
These results could have very real consequences. Doctors might not encourage smokers to quit if they believe it will be bad for the patient’s mental health. But if people with mental health problems light up more often, they may experience more physical problems and earlier death.
“Patients often say to me ‘doctor I’m too stressed to stop smoking now’. I hope doctors will now reassure those patients that there’s a good chance that stopping smoking will make you less stressed,” said Paul Aveyard, professor of behavioural medicine at Oxford University and the senior author of the study.
“In fact, for people with chronic mental health problems, stopping smoking might be an effective treatment.”
The researchers combed databases of published studies looking for high-quality research that assessed mental health before and after participants stopped smoking. The follow-up assessments took place anywhere between seven weeks and nine years after quitting. Participants in the 26 analysed studies include people living with chronic physical and/or psychiatric conditions, pregnant women, post-op patients, as well as people from the general population.
For a systematic review, researchers decide on a protocol for searching the literature with the aim of answering a hypothesis. Done well, it’s a thorough and enlightening way of analysing the results of many studies at once, reaching more solid conclusions than any single experiment. (To learn more, go read the wonderful book Bad Science by Ben Goldacre and check out the Cochrane Collaboration.)
The team suggested three possible explanations for their findings:
- Giving up tabs causes improvements in mental health
- Improvements in mental health lead people to renounce the snouts
- Something separate (a wonderful, positive event in your life, perhaps) explains both the quitting and the improved mental health
Most of the studies in this systematic review are observational (as opposed to being experiments), which means the researchers cannot tell whether stopping smoking causes improvements in mental health—just that there is an association (or, correlation).
“The rates of smoking in people with mental health problems have barely changed [over the last 40 years]. Part of this disparity is due to the myth that stopping smoking will worsen mental health”, said lead author Gemma Taylor, who is a doctoral researcher at the University of Birmingham.
“I believe this research debunks this myth and I hope that these findings motivate people with and without mental health problems to stop smoking.”
Reference: Taylor, McNeill, Girling, Farley, Lindson-Hawley & Aveyard – 2014. Change in mental health after smoking cessation: systematic review and meta-analysis. BMJ. PMID: 24524926