The study, published in the British Journal of Psychiatry, found that after successfully quitting smoking for six months, former smokers experience a significant decrease in anxiety levels.
The effect was greater among people with mood and anxiety disorders than those that smoked for pleasure.
The researchers said it seemed that smokers were more likely to have a cigarette soon after waking up to stave off withdrawal symptoms, which include anxiety. By quitting, they removed these repeated episodes of anxiety and felt less anxious as a result.
The study also suggests that a failed attempt seemed to increase anxiety levels somewhat among those who had mood disorders.
The researchers followed nearly 500 smokers attending National Health Service (NHS) stop smoking clinics in England. They suggest the findings should be used to reassure smokers attempting to quit that concerns about increased anxiety levels were unfounded.
Source: BBC News