Introduction: We examine a suspected causal association between tobacco smoking and depression. Using data from the National Household Survey on Drug Abuse (NHSDA), we explore variation in depression severity among current and former smokers compared to nonsmokers. We focus on the association between time since last smoke in former smokers and depression severity, to examine whether the level of tobacco-depression relationship might vary in a time-dependent fashion.
Methods: Our cross-sectional data come from three public use files of the U.S. National Household Survey on Drug Abuse (NHSDA), collected with different respondents each year from 1994 to 1996, for participants 12-17 years old (N = 13,827). Ordinal logistic regression is used to assess the association between severity of depression and cigarette smoking among former and current smokers.
Results: Current smokers had the highest odds for depression, followed by former smokers, then nonsmokers. Females had higher odds of depression compared to males. The odds of depression varied in subgroups of former smokers. Odds of depression were lower with more elapsed time since last smoke.
Discussion: We add new evidence on depression in association with tobacco smoking. Teens who quit smoking may reduce their odds of depressed mood, but more research is needed before a definite causal path can be established.