New scales to assess change in the addiction severity index for the opioid, cocaine, and alcohol dependent

Analyses were performed to construct and confirm the validity of new conjoi nt intake and 6-month follow-up scales for the Addiction Severity index (A. T. McLellan, L. Luborsky, G. E. Woody, & C. P. O'Brien, 1980) applied to a diverse sample of substance dependence patients (N = 1,008). A multistage scaling strategy identified 5 psychometrically integral addiction problem s cales. Exploratory item and factor analyses, confirmatory oblique item clus tering, and variance partitioning verified that the scales comprised relati vely little common variance and that each retained a substantial amount of unique and reliable variance. Resulting scales (Psychiatric, Drug, Alcohol, Family, and Legal Problems, respectively) were highly internally consisten t and structurally stable overall, at intake and follow-up and across gende r, age, ethnicity, and substance abuse categories. Concurrent and predictiv e validity over 2 years were supported for clinical subsamples based on com orbid psychopathology and mood, HIV risk behaviors, personality indices, ur ine toxicology, and criminal records.