Objectives: The disproportionately high smoking prevalence among persons with mental health problems has raised a concern that this population is at increased risk for smoking-related illness. We investigated the effect of smoking on mental health among US adults aged 18 and older using the 2000-2010 Behavioral Risk Factor Surveillance System (BRFSS).
Methods: Whereas previous literature has reported a significant association between smoking and mental health, identifying the causal pathway is difficult. To address the plausible reverse causality from mental health to smoking and omitted unobserved factors, we employ the method of instrumental variables (IV) by using state cigarette excise tax as an instrument for smoking.
Results: Our findings show that smoking increases the number of days with poor mental health especially among individuals with more severe illness (more than 14 days in the past month).
Conclusions: Our estimates suggest that smoking causes poor mental health and its effects are concentrated for measures that indicate more severe problems. Public health policies that aim to reduce smoking also may reduce poor mental health.