Association between smoking and mental disorders: Results from an Australian National Prevalence Survey

Objective: To assess the prevalence of mental disorders according to smoking status. Method: Data were taken from the National Survey of Mental Health and Wellbeing of Adults which was conducted by the Australian Bureau of Statistics in 1997. This survey involved a household sample of 10,641 adults aged 18+. The Composite International Diagnostic Interview was used to assess affective, anxiety and substance use disorders over the previous 12 months. Results: Smoking was found to be strongly associated with all categories of mental disorders, but the association varied by age. In people aged 18-39, current smokers had the highest prevalence of mental disorders, never smokers the lowest, and former smokers were in between. In the 40-59 age group, the results were similar, except that former smokers were more similar to never smokers. However, in the 60+ age group, smoking status was not associated with affective or anxiety disorders, and it was associated with substance use disorders only in males. Conclusions: The study confirmed that there is a strong relationship between mental disorders and smoking. However, the effect is age specific, being much stronger in younger adults than in the elderly. This age group effect could be due to a cohort difference in motivation for taking up smoking. Implications: Public health efforts to reduce the prevalence of smoking need to take account of the strong relationship between smoking and mental disorders.