The aim of this study was to understand the variation in response to alcohol use  by identifying classes of alcohol users based on alcohol-dependence symptoms and  to compare these classes across demographic characteristics, abuse symptoms, and  treatment usage. 
 Data from combined 2002-2005 National Survey on Drug  Use and Health identified 110,742 past-year alcohol users, age 18 years or  older. Latent class analysis defined classes based on observed clustering of  alcohol-dependence symptoms based on criteria from the Diagnostic and  Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Chi-square  statistics were used to test differences in sociodemographic and alcohol-abuse  characteristics across classes. Multivariable latent class regressions were used  to compare treatment usage across classes.
The four-class model had the  best overall fit and identified classes that differed quantitatively and  qualitatively, with 2.3% of the users in the most-severe class and 83.8% in the  least-severe/ not-affected class. These classes differed in a number of  demographic characteristics and alcohol-abuse symptoms. All individuals in the  most-severe class met DSM-IV criteria for alcohol dependence; 80% of this class  had alcohol-abuse symptoms. Twenty-six percent of the moderate and 50% of the  moderate-high class met dependence criteria. Approximately 19% of the  most-severe class and less than 5% of the moderate and moderate-high class  received treatment for alcohol in the past year.
 This study  demonstrates that meeting dependence criteria only partially captures variations  in responses to severity of alcohol problems. Although individuals in the  most-severe class were more likely to perceive need and receive treatment, the  percentage of individuals receiving treatment was low. 
 
