The first project objective is directed to developing a comprehensive computer interactive neuropsychologic test battery that is sensitive for detecting subtle disturbances of cerebral integrity. This task will be accomplished accessing a panel of neuropsychologists, an expert systems specialist and a software architect. Next, standardization will be conducted on 500 normal adolescents and adults. This sample will be stratified by age and gender and demographically representative of the population. Concurrent to these activities, an expert system will be created. This latter task will enable dissemination of the final protocol to the widest possible user audience. Finally, the interactive test battery will be used to ascertain the prevalence, types and severity of neuropsychologic deficit in samples of adolescent and adult drug abusers. The ultimate goal of this research program is to devise a standardized, quantitative and comprehensive method for characterizing the cognitive and psychomotor capacities of drug abusers. Computer interactive testing, because of its precision in measurement, will enable the detection of subtle or occult impairment residual to chronic drug abuse. For this reason, the battery is to be created specifically for this population. The information obtained from such an assessment has potentially important ramifications for determining the timing of treatment, type of treatment and post-treatment vocational rehabilitation of drug abusers.