Posttraumatic stress disorder and tobacco use: A systematic review and meta-analysis

Highlights

• This systematic review quantified the prevalence of comorbid PTSD and tobacco use.

• This study summarized factors associated with tobacco use in individuals with PTSD.

• Overall, high rates of comorbidity of PTSD and tobacco use were found.

• Negative affect was identified as a major contributing factor for tobacco use.

• Policies to reduce the burden of tobacco use among individuals with PTSD are proposed.

Abstract

Posttraumatic stress disorder (PTSD) and tobacco use are prevalent conditions that co-occur at striking rates in the US. Previous reviews examined prevalence and factors associated with cigarette smoking among individuals with PTSD but have not been summarized since 2007. Moreover, none explored rates and factors associated with the use of other tobacco products. This study aimed to systematically review the most recent literature examining the comorbidity of PTSD and tobacco use to provide prevalence rates, as well as summarize the literature exploring other factors associated with tobacco use among individuals with PTSD. Studies were identified using a systematic search of keywords related to tobacco use and PTSD within the following databases: PubMed, PsycINFO, Web of Knowledge, CINAHL, PsycARTICLES, and Cochrane Clinical Trials Library. The studies included in this review (N = 66) showed that the prevalence of current use of tobacco products in individuals with PTSD was 24.0% and the rate of PTSD among users of tobacco products was 20.2%. Additionally, results demonstrated that individuals with PTSD present with high levels of nicotine dependence and heavy use of tobacco products, as well as underscore the importance of negative emotional states as a contributing factor to tobacco use among individuals with PTSD. It is imperative that future studies continue monitoring tobacco use among individuals with PTSD while also assessing factors identified as having a prominent role in tobacco use among individuals with PTSD. These findings also demonstrate the need for more innovative approaches to reduce the pervasive tobacco use among individuals with PTSD.

Introduction

Posttraumatic stress disorder (PTSD) and cigarette smoking are prevalent conditions that co-occur at high rates in the US (Fu, McFall, Saxon, et al., 2007). The prevalence of cigarette smoking among individuals with PTSD has been estimated as high as 45% (Feldner, Babson, & Zvolensky, 2007; Fu et al., 2007; Kelly, Jensen, & Sofuoglu, 2015), approximately three times the rate of the general population (Jamal et al., 2016). PTSD can also further increase rates of cigarette smoking when co-occurring with other risk factors. For example, among veterans with PTSD, rates of cigarette smoking are as high as 66% (Fu et al., 2007). Although both PTSD and tobacco dependence are independently associated with high rates of mortality (Chesney, Goodwin, & Fazel, 2014; Walker, McGee, & Druss, 2015), there is evidence that smoking is a primary contributor to reduced life expectancy among individuals with PTSD (Boscarino, 2008; Tam, Warner, & Meza, 2016). Thus, it is critical to implement effective strategies to reduce the consumption of cigarettes among those with PTSD.

Prevalence of cigarette smoking in the general population has steadily reduced over the last decade, whereas rates of smoking have remained relatively stable among individuals with mental illness generally, as well as among individuals with PTSD specifically (Kelly, Jensen, & Sofuoglu, 2015; Stanton, Keith, Gaalema, et al., 2016). Various hypotheses have been proposed to explain the high co-occurrence of smoking and PTSD. The self-medication hypothesis, perhaps the most widely accepted explanation (Feldner, Babson, & Zvolensky, 2007), posits that individuals with PTSD smoke cigarettes as a way to lessen or cope with symptoms associated with their diagnosis (Khantzian, 1997). Another explanation is that there is a bidirectional relationship between PTSD and cigarette smoking (Fu et al., 2007), whereby individuals with PTSD symptoms initially smoke as a means to alleviate its symptomology, but as tobacco use increases it heightens PTSD symptoms (Leventhal & Zvolensky, 2015). The high co-occurrence of PTSD and smoking could also be due to shared vulnerabilities, such as genetic factors (Amstadter, Nugent, Koenen, et al., 2009), neurobiological structures (Enman, Zhang, & Unterwald, 2014), personality traits (Morisano, Bacher, Audrain-McGovern, & George, 2009), psychological mechanisms (Mathew, Cook, Japuntich, & Leventhal, 2015), or prior exposure to traumatic events (Feldner, Babson, & Zvolensky, 2007). Finally, other underlying factors that may explain continued smoking are the high levels of nicotine dependence or the severity of withdrawal symptoms that they experience (Fu et al., 2007; Jamal et al., 2016). In addition, individuals with mental illness have lower cessation rates in comparison with the general population (Prochaska, Das, & Young-Wolff, 2017). Many smokers with a mental illness report that they would like to quit, and in fact there is evidence that motivation to cease smoking among them is similar to those without a mental condition (Young-Wolff et al., 2014). Unfortunately, smokers with mental illness typically experience greater difficulty quitting smoking and poorer cessation outcomes due to their heavier smoking, greater nicotine dependence, and greater withdrawal symptoms (Lawrence, Mitrou, & Zubrick, 2009; Smith, Mazure, & McKee, 2014). Among individuals with PTSD in particular, the inability to tolerate elevated levels of negative emotional states, especially when confronted to trauma- and stress-related situations, has been suggested as one the leading factors for their lower quit rates (Cook, McFall, Calhoun, & Beckham, 2007). There is therefore an urgent need to understand the reasons for the high prevalence of cigarette smoking in smokers with PTSD and to identify the barriers that limit their capability to quitting smoking.

However, cigarette smoking is only one area of concern. The use of alternative tobacco products, such as combustible products (e.g., cigars) and non-combustible products (e.g., e-cigarettes) is rising, especially among smokers with mental illness (Cummins, Zhu, Tedeschi, Gamst, & Myers, 2014; Sawchuk, Roy-Byrne, Noonan, et al., 2012). For example, two recent epidemiological studies reported that e-cigarette use was twice as likely in individuals with a mental condition compared to those without (Cummins et al., 2014; Spears, Jones, Weaver, Pechacek, & Eriksen, 2016). Given the high unemployment rates among people with PTSD, (Spears et al., 2016) it is likely that the lower prices of little cigars and cigarillos may contribute to elevated rates of use of these products among people with PTSD (Miller, Tidey, Bunn, et al., n.d.). Given their low quit rates, people with PTSD may be particularly likely to use non-combusted tobacco products to reduce their smoking rate (Cummins et al., 2014; Hefner et al., 2016). However, actual rates and factors that underlie alternative tobacco product use in this population are unknown.

Prior reviews have examined co-ocurrence and factors associated with cigarette smoking among individuals with PTSD (Feldner, Babson, & Zvolensky, 2007; Fu et al., 2007; Kelly, Jensen, & Sofuoglu, 2015; Tidey & Miller, 2015). Two of these reviews provided a systematic summary, but included data from studies published before 2007. Also, none used a meta-analytic approach to summarize and statistically integrate results of independent studies. Instead, these reviews provided largely divergent prevalence estimates or combined prevalence estimates using simple pooling techniques which have limited utility as metrics of the actual rates of PTSD and cigarette smoking. Moreover, while these reviews focused on the rates of cigarette smoking among individuals with PTSD, they did not examine the prevalence of PTSD among smokers, mainly due to the lack of studies providing these estimates. It is also noteworthy that no review has explored rates and factors associated with the use of other tobacco products, despite existing evidence indicating that individuals with PTSD frequently use novel/alternative tobacco products (Hefner et al., 2016; Sawchuk et al., 2012). Thus, understanding the co-occurrence of tobacco use and PTSD is both necessary and timely since this information may guide policy making, identify research priorities, and show changes and trends over time. The overall purpose of this study was to conduct a systematic review of the most recent literature examining the comorbidity of PTSD and tobacco use. The specific aims were to quantify the co-occurrence of PTSD and tobacco use, and summarize the literature exploring factors associated with tobacco use among individuals with PTSD.