MEASUREMENT PROPERTIES OF QUANTITATIVE URINE BENZOYLECGONINE IN CLINICAL-TRIALS RESEARCH

Psychometric data are presented which examine the validity of using th e concentration of benzoylecgonine in urine, a. major metabolite of co caine, as a measure of drug use, in studies of drug abuse treatments. In such research the standard biological indicator of drug use is usua lly a qualitative urine drug test, which merely indicates the presence or absence of a drug or its metabolite. A quantitative (i.e. continuo us) outcome measure, such as the concentration of a drug or its metabo lite in a biological fluid, has substantially more statistical power t han a dichotomous measure and should, therefore, prove a more sensitiv e measure of drug use when viewed from a measurement perspective. Data from two placebo-controlled clinical trials of fluoxetine as an adjun ct to treatment for cocaine abuse are analyzed to address this issue. Results indicate that urine benzoylecgonine level is closely related t o self-reports of drug use and is independent of levels of anxiety, de pression and hopelessness.