The mean number ± standard deviation of dependence criteria endorsed (1.30±1.60 in the entire sample) increased in each successive class (class 1: 0.27±0.45, class 2: 2.29±0.83 and class 3: 5.03±1.27) and differed significantly by class, K (2, N = 361) = 282.24, p < .001. Endorsement of withdrawal was relatively low in all three classes. There were similarities and differences in criterion endorsement between classes 2 and 3. Similar class probabilities were observed for tolerance and drinking more than intended (Figure 1). However, in contrast to class 2, class 3 endorsed spending a great deal of time drinking and continued use despite problems at the same frequency as drinking more than intended. Although classes 2 and 3 tended to be heavy episodic drinkers, these classes did not contain a significantly higher percentage of males than class 1 (class 1=25.4%, class 2=28.1%, class 3=31.0%), nor did they differ significantly by age (class 1: M = 19.15 [SD = 2.57], class 2: M =18.79 [SD = 1.07], class 3: M =18.93 [SD = 0.94]) or likelihood of having a positive family history
