A man smoking a cigarette.
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Quitting smoking is known to have benefits for physical health, including a reduced risk of cancer and heart disease, but a new study suggests that giving up the habit may improve mental health as well.
In the study, researchers reviewed information from 26 previous studies, and found that people who quit smoking had a reduction in feelings of depression, anxiety and stress, and an increase in positive mood and quality of life, after they quit, compared with those who continued smoking. This finding was true for people in the general population as well as those with mental health disorders, the researchers said.
The findings contradict the widely held assumption that smoking is good for mental health: many smokers continue smoking because they feel that the habit alleviates feelings of depression, anxiety and stress, and helps them relax, the researchers said. [Kick the Habit: 10 Scientific Quit-Smoking Tips]
But the cigarettes may actually be alleviating withdrawal symptoms, including irritability, anxiety and depression, which smokers misperceive as improving mood, the researchers said. Some studies suggest that these withdrawal symptoms abate a few weeks after quitting.
"Smokers can be reassured that stopping smoking is associated with mental health benefits," the researchers wrote in today's (Feb. 13) issue of the journal BMJ. By challenging previous assumptions about smoking's effect on mental health, the findings may motivate some smokers to stop, the researchers said.
Still, the study cannot prove a cause-and-effect relationship between quitting and mental health improvements. For example, it's possible that people who experience improvements in mental health are those who attempt to quit smoking.
But the researchers noted that many of the studies in their review were smoking cessation trials in which all participants attempted to quit. So in these trials, the decision to quit was not based on mood, they said.
For their review, the researchers chose studies that assessed mental health before and at least six weeks after smoking cessation. On average, the participants had smoked 20 cigarettes per day, and were followed for six months.