Although both the subtyping approaches of Babor et al. (1992) and Cloninger (1987) are of theoretical interest, neither can be applied easily to patient care, as the cluster analytic approach demands a moderately large sample and is applied post hoc and Cloninger’s approach does not categorize all patients (Lamparski et al. 1991). However, age of onset alone may be a clinically meaningful approach to categorizing alcoholic subtypes (Irwin et al. 1990; Johnson et al. 2000b). Roache et al. (2008) used a similar approach in a sample of patients participating in a placebo-controlled trial of ondansetron (Johnson et al. 2000a) and obtained a 2-cluster solution similar to that obtained by Babor et al. (2002). The same patients were grouped into EOAs (onset at ≤ 25 years of age) or LOAs (onset at > 25 years of age) using a single question about the age at which drinking problems began. Seventy-two percent of high-risk/vulnerability (Type B) patients were EOAs and 67% of low-risk/vulnerability (Type A) patients were LOAs. Although Type B alcoholics had a better response to treatment with ondansetron than placebo, age of onset was a substantially better moderator of this response than the cluster-derived subtypes.
