, 2004) and in enriched/clinic samples (Moolchan et al., antagonist Bicalutamide 2002; Strong, Brown, Ramsey, & Myers, 2003), this low concordance is reflected by kappas of .3 and lower. Furthermore, studies show that DSM-based assessments of nicotine dependence more frequently correlate with psychopathology, such as major depression (Breslau & Johnson, 2000), while the FTND is more closely related to tobacco liking (Moolchan, Aung, & Henningfield, 2003; Strong et al., 2003). Despite the limited overlap across these two popular assessments, few studies have attempted to simultaneously analyze DSM-IV and FTND criteria to examine whether they characterize smokers in a similar or different manner. As noted, individuals with DSM-IV nicotine dependence do not systematically meet criteria for FTND-based nicotine dependence (and vice versa).

By examining both sets of criteria simultaneously we can better understand endorsement of criteria across these two constructs. Importantly, this can demonstrate the synergy across the two assessments in providing comprehensive information on how common and specific aspects of the two assessments work in tandem to produce vulnerability to nicotine dependence. Thus, the goals of this study are (a) to utilize self-reported DSM-IV and FTND criteria to classify individuals using latent class analysis; (b) to examine sociodemographic, smoking-related, and other psychiatric correlates of each class; and (c) to contrast the latent classes in terms of latent genetic and environmental vulnerability.

Materials and Methods Sample Data for this study come from 624 adolescent/young adult offspring of Vietnam Era Twins who were regular cigarette smokers. Fathers were members of the Vietnam Era Twin Registry (VETR; Eisen, True, Goldberg, Henderson, & Robinette, 1987; Goldberg, True, Eisen, Henderson, & Robinette, 1987; Henderson et al., 1990), which is a national registry of male like�Csex twin pairs in which both cotwins served in the military during the Vietnam Era (1965�C1975). Construction of the registry and method of determining zygosity have been previously reported (Eisen et al., 1987). In 1987, twins were first surveyed about their general health including number of offspring fathered by them. In 1992, twins were interviewed by telephone with the Diagnostic Interview Schedule (Robins, Helzer, Cottler, & Goldring, 1988).

In 2001 and 2004, respectively, data collection was initiated for two offspring of twins (OOT) studies, which aimed to examine outcomes in the children of VETR twin fathers who (a) Dacomitinib were concordant or discordant for alcohol dependence (AD, Project 1) or (b) were concordant or discordant for illicit drug dependence (DD, Project 2), along with (c) unaffected control twin pairs. Both OOT projects used an adaptation of the Semi-Structured Assessment for the Genetics of Alcoholism (Bucholz et al., 1994) to collect data from mothers and offspring.