THE TOPOGRAPHY OF RELAPSE IN CLINICAL-SAMPLES

In two clinical samples, alcohol consumption, other drug use, and toba cco use were measured at approximately 6 months following admission of individuals into treatment. Using only the alcohol consumption variab les, cluster analyses with several different solutions consistently id entified abstinent, moderate, and unremitted groups. With the addition of tobacco and other drug use, analyses identified a largely abstinen t group, a drug use group that did not drink, a heavy drinking group t hat did not use other drugs, and a group using both alcohol and other drugs, indicating the need for broad definitions of relapse. All solut ions distinguished clusters of tobacco users and nonusers in remission from alcohol and other drug use, and tobacco users and nonusers tende d to be differentiated among those continuing to drink or use other dr ugs, suggesting that the presence or absence of tobacco use marks diff erent outcome groups. Generally speaking, clustering methods using com plete and average linkage as agglomeration measures with cosine simila rity as a proximity measure produced the most consistent clusters and the most clinically interpretable results. (C) 1998 Elsevier Science L td.