Context: Although several risk factors for tobacco use have been implicated in the development of depression, smoking progression has typically been viewed as a consequence of depression. The results of limited longitudinal studies are controversial.
Objective: To assess the nature and direction of the relationship between cigarette smoking and depression among teens.
Design: Prospective analysis of baseline and 1-year follow-up data from the National Longitudinal Study of Adolescent Health.
Setting: In-home teen and parent interviews.
Participants: Two samples were identified. For the first sample, 8704 adolescents who were not depressed at baseline based on CES-D scores were identified for analyses of the effects of cigarette smoking on development of high depressive symptomatology. Baseline smoking status, which could vary in this group, was the predictor of interest in these analyses. For the second sample, 6947 teens who had not smoked cigarettes in the 30 days before the baseline survey (noncurrent smokers) were identified for analyses on the effect of high depressive symptoms on subsequent moderate to heavy cigarette use at 1 year of follow-up. Baseline high depressive symptomatology based on CES-D score was the predictor of interest in this sample.
Main outcome measures: Among the nondepressed, developing high depressive symptoms at 1 year of follow-up. Among noncurrent smokers, smoking at least 1 pack per week at 1 year of follow-up.
Results: For the nondepressed, multivariate modeling revealed that current cigarette smoking was the strongest predictor of developing high depressive symptoms in all models (final model odds ratio [OR]: 3.90; 95% confidence interval [CI]: 1.85,8.20). For noncurrent smokers, although in bivariate analyses, baseline high depressive symptoms increased the risk of heavy smoking nearly threefold, multivariate modeling revealed that baseline high depressive symptoms were not predictive of heavy smoking when controlling for other determinants of smoking in teens. Previous experimentation with smoking was the strongest predictor of becoming a heavy smoker (OR: 3.04; 95% CI: 1.93,4.88).
Conclusions: In contrast to common dictum, depression does not seem to be an antecedent to heavy cigarette use among teens. However, current cigarette use is a powerful determinant of developing high depressive symptoms.