The first phase of the protocol, screening assessment, consists of documenting the client's background in the Personal History Form and administering and scoring the Drug Use Screening Inventory (DUSI). A decision tree approach is used to accrue the results in areas of health, psychiatric, and psychosocial disturbance. Ten domains are selected for screening based on their etiologic relationship to substance abuse or contribution to sustaining drug use behavior and their amenability to treatment intervention. The ten domains are substance use behavior, behavior patterns, health status, psychiatric disorder, social skill, family system, school, work, peer relationship, and leisure and recreation. The second phase of the protocol is the diagnostic evaluation using the DUSI. In the final phase, the treatment plan is formulated, based on objective diagnostic information. 7 tables, 21 references. (Author abstract modified)