A second interpretation is that nicotine and alcohol abuse may share common vulnerability pathways to addictions, Brefeldin A mechanism such that the comorbid abuse of these substances represents the more severe forms of the combined disorders. Morisano, Bacher, Audrain-McGovern, and George (2009) put forth this hypothesis and suggest that shared biological, genetic, and environmental vulnerabilities to each disorder may contribute to comorbidity. In either case, it appears clear that in this sample of alcoholics, smokers reported greater alcohol consequences and physical dependence relative to former smokers and in the presence of more frequent abstinent days. Interestingly, data exist, which suggest that the converse may be true as well��that smokers with alcohol dependence may exhibit more severe nicotine dependence than nonalcohol dependent individuals (Hughes, 1996; Kahler et al.

, 2010). At a minimum, our findings suggest that smoking status may be a marker for severity of alcohol dependence and symptoms in alcoholics. Interestingly, alcoholic smokers attended substantially fewer treatment sessions relative to both nonsmokers and former smokers. Greater problem severity among the alcoholic smokers may cause them to be more likely to drop out of outpatient treatment, or perhaps alcoholic smokers find the nonsmoking treatment environment too restrictive (even for the relatively short periods of enforced abstinence). Regardless of possible interpretations for this finding��that alcoholic smokers participated on average in less than one-half of the outpatient treatment sessions, whereas nonsmokers and former smokers participated on average in two-thirds of sessions or more��this treatment dropout is cause for concern.

It suggests that the most severe alcoholics, the alcoholics who smoke, typically avail themselves of the fewest outpatient treatment sessions. These findings should be viewed with several caveats. The sample is predominantly White, and treatment took place in an outpatient setting. Clients who were mandated to treatment were excluded from participation in the study. Caution should be used before generalizing to other populations of alcoholics or alcoholics who are not enrolled in treatment. Also, our assessment of Entinostat nicotine involvement was brief and relatively narrow. Categorization based on nicotine dependence, such as with the Fagerstr?m Test for Nicotine Dependence (Fagerstr?m, 1978), may have yielded a different pattern of results. Conclusions The rate of smoking was profoundly elevated in this sample of treatment-seeking alcoholics��45% were daily smokers. Alcoholic smokers scored similarly to nonsmokers and former smokers in terms of personality.