Treatment benefit functions for a drug abuse rehabilitation treatment system.

While generally justifying the large amount of money invested in the treatment effort, evaluation studies of treatment centers for drug addiction do not offer a rational method of allocating scarce resources among the various available treatment programs. The problem is further confounded by different costs associated with the different programs and also because clients rarely complete the prescribed treatment. We developed functional relationships between treatment outcomes and time in treatment that allow the inclusion of probable length of stay of patients and cost per week for a particular treatment program in the evaluation considerations. The model evolved from a drug addiction treatment system operating in Newark, New Jersey consisting of six different treatment centres. Treatment outcome measures are derived from a psychosocial questionnaire which was administered to patients at appropriate time intervals. The questionnaire probed into the important facets of human behavior as related to the use or non-use of drugs for non-medical reasons. Gompertz curves reflecting treatment benefit are computed for each treatment center by least square fit of the collected data to appropriate differential equations and used together with cost of treatment and treatment retention rates to compute expected net benefit for each treatment center. These enable the researcher to find the treatment centers with the best treatment outcome or alternately with the best expected cost benefit ratio for any patient type.