Aims: To examine comorbidity between tobacco use, substance-use disorders and mental health problems among Australian adults aged 18 years and over.
Method: Data from the 1997 Australian National Survey of Mental Health and Well-being were analyzed. This survey was a stratified, multistage probability sample of 10,641 adults, representative of the Australian population. Univariate associations between tobacco use, substance use and mental health were examined, and then multivariate analyses were conducted to control for demographic characteristics, neuroticism, and other drug use.
Measurements: Tobacco use status was defined as: never smoker, former smoker and current smoker. DSM-IV diagnoses of substance use, anxiety, and affective disorders were derived using the Composite International Diagnostic Interview (CIDI). Other measures included a screener for psychosis and measures of psychological distress and disability.
Findings: Current tobacco use was strongly associated with abuse/dependence upon alcohol, cannabis, and other substances, and with higher rates of anxiety and affective disorders. Current smokers were more likely to screen positively for psychosis and reported greater psychological distress and disability than non-smokers and never smokers. These higher rates of other problems were not explained by differences in demographic characteristics, neuroticism scores, or by other drug use. Former smokers did not have higher rates of affective or anxiety disorders; however, they had higher rates of alcohol-use disorders, and of cannabis-use disorders after adjusting for covariates.
Conclusions: Current tobacco use is associated with a range of other substance-use and mental health problems. These are likely to reduce the success of attempts to quit smoking. The presence of these other problems needs to be considered when considering smoking-cessation treatment, and further research may provide information on more effective treatment strategies for persons with co-existing substance-use and mental health problems.