Change in Mental Health after Smoking Cessation

Summary

A Cochrane review [Abstract] 3 examining the association between smoking cessation and change in mental health included 102 studies with over 169 500 participants. Smoking cessation was associated with an improvement in mental health symptoms compared with continuing to smoke: anxiety symptoms (SMD −0.28, 95% CI −0.43 to −0.13; 15 studies, n=3141); depression symptoms: (SMD −0.30, 95% CI −0.39 to −0.21; 34 studies, n=7156); mixed anxiety and depression symptoms (SMD −0.31, 95% CI −0.40 to −0.22; 8 studies, n=2829); stress (SMD −0.19, 95% CI −0.34 to −0.04; 4 studies, n=1792), and psychological quality of life (SMD 0.11, 95% CI 0.06 to 0.16; 19 studies, n=18 034).

A systematic review1and meta-analysis included 26 observational studies (11 cohort studies, 14 secondary analyses of cessation interventions, 1 RCT) in healthy and clinical populations. The aim was to investigate change in mental health after smoking cessation compared with continuing to smoke assessing mental health with questionnaires designed to measure anxiety, depression, mixed anxiety and depression, psychological quality of life, positive affect, and stress. Follow-up mental health scores were measured between 7 weeks and 9 years after baseline. The median length of follow up was 6 months. In 18 studies abstinence was biologically verified. In 7 studies participants received a psychological intervention as part of the cessation intervention. Anxiety significantly decreased between baseline and follow-up in quitters compared with continuing smokers (the standardised mean difference (SMD) −0.37 ;95% CI −0.70 to −0.03; 4 trials; I²=71%; P<0.03), so did depression (SMD −0.25;−0.37 to −0.12; 10 trials; I²=30%; P<0.001), mixed anxiety and depression (−0.31; −0.47 to −0.14; 5 trials, I²=0%; P<0.001), and stress (-0.27; −0.40 to −0.13; 3 trials; I²=0%; P<0.001). Both psychological quality of life and positive affect significantly increased between baseline and follow-up in quitters compared with continuing smokers 0.22 (0.09 to 0.36; 8 trials; I²=63%; P<0.001) and 0.40 (0.09 to 0.71; 3 trials;, I²=49%; P<0.01), respectively. There was no evidence that the effect size differed between the general population and populations with physical or psychiatric disorders.

A meta-analysis 2 assessed smoking cessation interventions for smokers with current depression. 16 RCTs and 4 secondary studies were included. 3 types of intervention were examined: psychological (6/30%), pharmacological (6/30%) or combined (8/40%). Smoking cessation interventions appear to increase short-term (RR 1.26, 95% CI 1.12 to 1.41, p < .001, I²=64%) and long-term (RR 1.14, 95% CI 1.01 to 1.29, p = .048, I²=42%). Psychological treatments found a positive trend, although not significant, at both short and long-term follow-up. Smoking abstinence appears to be associated with an improvement in depressive symptoms.