The frequency and quantity of cigarette smoking is highly related to nicotine dependence level, the severity of withdrawal during abstinence, and numerous other smoking-related variables. For example, heavy daily smokers have demonstrated greater nicotine dependence, withdrawal symptoms, cigarette craving, difficulty quitting smoking (Dale et al., 2001; Killen, Fortmann, Telch, & Newman, 1988; Nides et al., 1995), tolerance to nicotine’s subjective and cardiovascular effects (Perkins, 1995; Perkins, Epstein, Stiller, Marks, & Jacob, 1989), and more health-related problems than light daily smokers (Wilson, Parsons, & Wakefield, 1999). Non-daily smokers often do not display signs of nicotine dependence or report symptoms of withdrawal after prolonged abstinence (Shiffman, Dunbar, Scholl, & Tindle, 2012; Shiffman, Paty, Gnys, Kassel, & Elash, 1995); yet, their ad libitum smoking behavior, as measured by EMA, has been positively associated with NA (Shiffman et al., 2012; Shiffman & Paty, 2006), which is contrary to findings in heavy daily smokers (Chandra et al., 2011; Shiffman et al., 2002; Shiffman & Waters, 2004). In both daily and non-daily smokers, cigarette-related cues increase craving in the laboratory (Shiffman et al., 2013) and PA appears to be positively associated with smoking behavior in ad libitum conditions in the natural environment (Shiffman et al., 2014).
