Smoking cessation, anxiety, mood and quality of life: reassuring evidences.

A close and complex relationship between smoking and mental health problems was found. Different hypotheses have been proposed to explain these associations: 1) smoking and poor mental health may share common causes (genetic factors or environmental mechanisms); 2) for people with poor mental health smoking is a coping strategy to regulate psychiatric symptoms; 3) smokings worsen mental health. Moreover, smokers with psychiatric disorders may have more difficulty quitting and patients with mental diseases who received mental health treatment within the previous year were more likely to stop smoking than those not receiving treatment. Taylor et al. hypothesized that quitting smoking might improve rather than exacerbate mental health, because it allows to avoid multiple episodes of negative affect induced by withdrawal. With the aim to verify this hypothesis, they conducted a systematic review and meta-analysis on longitudinal studies (randomized controlled trials and cohort studies) in which the difference in change in mental health between subjects who stop smoking and subjects who continue to smoke has been explored. A total of 26 longitudinal studies evaluating anxiety, depression, mixed anxiety and depression, positive effect, psychological quality of life, and stress have been included. The study results provided enough evidence to assure that quitting smoking is associated with a reduction of depression, anxiety, and stress, with an improvement of psychological quality of life and positive affect compared with continuing to smoke. The strength of association was similar for both the general population and study enrolled populations, including those with mental health disorders. The results of this meta-analysis have direct clinical implications: the benefits for mental health could motivate physicians and patients to take into account the possibility of smoking cessation.