The role of mental illness on cigarette dependence and successful quitting in a nationally representative, household-based sample of U.S. adults

Abstract

Purpose

To begin to explore whether the association between mental illness (MI), cigarette dependence, and unsuccessful quit attempts differs across particular demographic subgroups.

Methods

This study examines data from adults aged 18 years or older participating in the 2008–2012 National Surveys on Drug Use and Health. Analyses explored the moderating effects of age, gender, and race and/or ethnicity on associations between three levels of MI: (serious mental illness [SMI], any mental illness but no SMI, and no MI) and two smoking-related outcomes (cigarette dependence among current smokers and successful quitting among ever daily smokers).

Results

After confirming that adults with MI were more likely to be dependent on cigarettes and less likely to successfully quit smoking, particularly among those with SMI, adjusted analyses indicated that age (but not gender or race/ethnicity) moderated the associations between MI and cigarette dependence and between MI.

Conclusions

The magnitude of the association between MI and cigarette dependence and between MI and successful quitting appears to be stronger among older adults than among younger adults. Identifying subgroups at particular high risk of cigarette dependence is paramount to targeting smoking prevention, cessation, and treatment services appropriately.

Introduction

Cigarette smoking continues to be one of the world's largest public health problems despite significant advances in the recognition of its adverse effects on health and well-being [1]. People with mental illness (MI) are at particular risk for cigarette-related negative health outcomes because they have higher rates of having ever-smoked cigarettes [2], [3], [4], smoke more cigarettes per day [5], [6], have higher rates of nicotine dependence [7], [8], [9], and suffer more smoking-related morbidity and mortality [10] than people without MI. These problems have made smoking prevention and cessation among those with MI—particularly serious MI (SMI)—a national priority [11]. Although the prevalence of smoking appears to be decreasing in the population overall [12], the prevalence is not decreasing as much among those with MI [13], and individuals with MI are less likely to successfully quit smoking than those without MI [2], [4], [6], [14], [15].

Research indicates that a substantial proportion of people with MI has a desire to quit smoking [16], [17] and that smoking cessation interventions can be effective among those with MI [18], [19]. This suggests that targeted interventions for cessation may be useful for reducing the smoking burden among those with MI. However, identifying where prevention and cessation programs may be optimally implemented is important, given limited resources.

Some evidence suggests that the relationship between smoking status and MI may not be the same across all subpopulations. For example, data from the 2007 Health Information National Trends Survey found that general psychological distress was related to current smoking for white but not for black or Hispanic respondents [20]. Whether these differences by race and/or ethnicity extend to the association between MI and cigarette dependence, however, is unknown. To our knowledge, no published studies have formally assessed the moderation of MI and cigarette dependence by other demographic characteristics such as gender or age that might influence the association between mental illness and cigarette dependence. Likewise, it is important to adjust for other sociodemographic covariates such as employment, education, and income which have been indicated as having significant associations with both mental illness and smoking outcomes [21].

Additionally, there is a paucity of research examining the interaction between MI and demographic characteristics on successful quitting. One prospective study of >4000 adults in the United States found that the relationship between depression symptoms and smoking cessation was not significantly moderated by gender or race. However, that study only included white and black respondents, and it did not examine age [22]. Moreover, the study focused only on depression symptoms and did not evaluate other mental illnesses.

This study builds on past work by using recent, nationally representative data from the National Survey on Drug Use and Health (NSDUH) to begin to explore whether the associations between MI and cigarette dependence, and MI and successful quitting are moderated by age, gender, and race and/or ethnicity in covariate adjusted models. This investigation is paramount because there is only limited evidence regarding the moderation of the association between MI and cigarette dependence and quitting, especially in population-based samples. Age, gender, and race and/or ethnicity were selected as the first three potential moderators for investigation because these characteristics are easily identified during a clinical encounter thereby making them potentially useful markers for targeting prevention and treatment efforts. Moreover, prior research has shown that rates of MI differ by age, gender, and race/ethnicity, as do rates of cigarette dependence and successful quitting [11], [23], [24], and there may be a differential relationship between MI and cigarette dependence or quitting, and age, gender, and race/ethnicity. NSDUH allows for a refined investigation of this moderation (e.g., examining six racial/ethnic groups and three levels of MI) because of its large sample size and national representativeness. Better understanding of these associations in specific subpopulations may help treatment and service providers identify those most at need for additional prevention and cessation services and may help future researchers identify etiological mechanisms.