Smoking and mental disorders: associations derived from longitudinal data over 20 years

Abstract

Background:

To examine the associations between tobacco use and a broad spectrum of mental disorders using longitudinal population based data over 20 years.

Methods:

The data were derived from the Zurich Study – a longitudinal community study which started in 1979 with a stratified sample of 591 participants aged 20/21 years. Follow-up interviews were conducted at age 23, 28, 30, 35 and 41. Statistical analysis relies on logistic regression and longitudinal data analysis. The analyses focussed on smokers (having ever regularly smoked) and on strong smokers (having ever smoked more than 22 cigarettes per day).

Results:

In general, a lifetime diagnosis of mental disorders yields a heightened risk for smoking (OR ~ 4) and being a strong smoker (OR ~ 6) up to age of 40. The risk is particularly high in substance use, but also in dysthymia and bipolar diagnoses (OR > 15). At the other end of the scale are obsessive-compulsive disorder and bulimia with ORs almost similar to the general population. Simple phobia, agoraphobia, panic disorder and neurasthenia do not differ in terms of ever smoking, however their ORs are astonishingly high in strong smokers.

Conclusions:

The risk of being (or having been) a smoker differs distinctly by mental disorder. This is most apparent in mood disorders. Moreover, in another group of disorders the amount of smoking interplays in a particular way. It seems unlikely that the causal linkage follows a consistent pattern.