Background: Evidence shows considerable comorbidity between nicotine dependence and depression. However, little is known from the population about specific factors involved. The goal was to analyze smoking, nicotine dependence, and depression cross-sectionally and to analyze whether or not depression predicts the sustenance of smoking after 3 years.
Method: A population-based random sample, representative for the adult population aged 18 to 64 years in a German region, was interviewed face to face (N = 4075). Among these were 2458 daily smokers, of whom 320 (13.0%) had a lifetime diagnosis of depression. Current smokers at baseline were followed up 36 months later. Measurements included DSM-IV diagnoses of depression and nicotine dependence by the Composite International Diagnostic Interview. Smoking cessation was defined as the abstinence from smoking for at least 4 consecutive weeks.
Results: The rate of subjects with a depressive disorder among female never nicotine dependents was 13.7% and among female current nicotine dependents 31.6% (chi(2) = 49.9, df = 2, p <.001); the respective rate among male never nicotine dependents was 5.6% and among male current nicotine dependents 13.4% (chi(2) = 20.2, df = 2, p <.001). Subjects with a lifetime history of depressive disorder revealed the same rate of smoking cessation after 3 years as those without a depressive disorder (chi(2) = 0.7, df = 1, not significant). The use of nicotine replacement therapy was equally distributed among subjects with a depressive disorder and those without a depressive disorder (chi(2) = 0.03, df = 1, not significant).
Conclusion: The risk for depression increases as the number of nicotine dependence symptoms increases or dependence criteria are fulfilled. Despite this association, depressed subjects may show the same prospect for smoking cessation as nondepressed subjects.