Smoking and common mental disorders: A population-based survey in Santiago, Chile

Background: Smoking and common mental disorders (CMD), anxiety and depression, tend to co-exist and are important public health challenges for countries at all levels of development. We aimed to study the association between smoking and common mental disorders after adjusting for alcohol, illicit drug use and other confounders. Methods: Cross-sectional household survey. CMD were assessed with a detailed psychiatric interview and smoking, alcohol, and illicit drug use with self-reported questionnaires. Results: About 3,870 randomly selected adults were interviewed of whom 12.9% (95% CI 12-15) met criteria for ICD-10 CMD diagnoses. 38% (36-40) of the respondents were current smokers and 11% (10-13) ex-smokers. There was a robust association between heavier smoking and the presence and severity of CMD. However there were no major differences between non-smokers, ex-smokers and light smokers. In the fully adjusted models those individuals with ICD-10 CMD were significantly more likely to be current smokers [OR 1.6 (1.1-2.2)]. Smoking was also strongly associated with drinking heavily [OR 5.4 (4.0-7.3)] and illicit drug use [(OR 2.1 (1.1-4.1)] but there were no significant interactions. Conclusions: Smoking is highly prevalent and associated with CMD and other addictive behaviours in Chile. These are major public health problems in need of urgent action.