An Exploration of Heterogeneity in an Inpatient Male Alcoholic Population*

This study investigated whether the 11 personality scales of the Millón Clinical Multiaxial Inventory (MCMI) would reveal meaningful heterogeneity in an inpatient male alcoholic sample. A cluster analysis of the MCMI personality scale scores of 126 inpatients yielded four psychometrically distinct subgroups that met the criteria for selection of clusters. Differences between the clusters were tested for on a range of member characteristics and on questionnaire items relevant to a comprehensive view of the etiology and treatment of alcoholism. Significant differences between clusters were found for age, religion, type of substance use problem, and treatment completion. Tests on questionnaire items yielded significant differences on the subjects' reports of their ages when drinking became a problem, whether they had ever experienced alcohol–related seizures, and whether their current treatment was mandated by the criminal justice system. The largest number of significant differences between clusters were found on items relating to psychological functioning. Post hoc analyses suggested a coherence between the meaning, including level of dysfunction, implied by the cluster profiles and the pattern of differences between clusters on nontest variables. Implications of the results include the importance of recognizing the heterogeneity of the inpatient male alcoholic population and the potential value of using measures of the more enduring modes of functioning to better understand and treat this population, as well as the need for replication and further research in this area.