We developed a lifetime severity index for cocaine use disorder and examined its predictive validity of posttreatment outcome using data from the national Drug Abuse Treatment Outcome Study. The index, based on 28 items, considered frequency of use, recency, dependency, and attempt to quit. A higher value of the index, indicating greater severity, predicted a greater likelihood of relapse (the odds ratios were 5.7 for high severity and 4.4 for medium severity, relative to low severity) and shorter time to relapse. Similarly, the polytomous logistic analysis indicated that the index predicted levels of posttreatment cocaine use (odds ratios of daily use were 47.8 for the high severity and 18.8 for medium severity; the corresponding odds ratios of weekly use were 6.75 and 5.10 and for less-than-weekly use were 3.35 and 3.57). The index can be a useful measure for both clinical and research purposes.
1 Drug Abuse Research Center, University of California, Los Angeles, 1640 Sepulveda Blvd., Suite 200, Los Angeles, California 90025. Send reprint requests to Dr. Hser.
This work was supported by grant U01-DA10378 from the National Institute on Drug Abuse (NIDA). This grant is part of the Drug Abuse Treatment Outcome Studies (DATOS), a NIDA-funded collaborative effort involving the National Development and Research Institutes, the Institute of Behavioral Research at Texas Christian University, the UCLA Drug Abuse Research Center, and NIDA scientists. Drs. Hser and Anglin are also supported by NIDA Research Scientist Development Awards (K02-DA00139 and DA00146, respectively). Interpretations of the results and conclusions in this paper, however, do not necessarily represent the position of other collaborating DATOS Research Centers, NIDA, or the Department of Health and Human Services. The authors wish to thank staff at the UCLA Drug Abuse Research Center for assisting in the data analyses and manuscript preparation.