These studies consistently support a unidimensional model, but their applicability to clinical populations cannot be assumed because the criteria are likely to be distributed differently in patient and non-patient populations. Earlier studies in clinical samples addressed earlier nosologies (Bryant et al., 1991; Hasin et al., 1988; Kosten et al., 1987; Rounsaville et al., 1993) did not include complete (or any) coverage of DSM-IV abuse (Feingold and Rounsaville, 1995a; Kosten et al., 1987; Morgenstern et al., 1994; Rounsaville et al., 1993) or measured dependence criteria with a diagnostic instrument and abuse in a different manner (Feingold and Rounsaville, 1995b). Several studies mixed patients and non-patients (Bryant et al., 1991; Feingold and Rounsaville, 1995a,b; Nelson et al., 1999; Rounsaville et al., 1993). Varying analytic strategies across these studies reflected the evolution in latent variable methodology during this period. These studies were inconsistent on the number and content of factors obtained, and do not directly answer the questions at hand for the proposed DSM-5 SUD changes.
