AN ANTAGONIST IS A DRUG THAT ACTS IMMEDIATELY TO BLOCK THE TYPICAL 'HIGH' WHEN NARCOTICS ARE TAKEN WITHIN VARIOUSLY LIMITED TIME SPANS. ON CONTINUED ADMINISTRATION, IT ACTS TO PREVENT PHYSICAL DEPENDENCE. ITS USE IS BASED ON THE THEORY THAT THE ELIMINATION OF THE ELIMINATION OF THE SATISFACTIONS OF NARCOTICS USE WILL RESULT IN A DECREASE IN ITS INTAKE AND, EVENTUALLY, IN ITS ELIMINATION. PRIOR TO THE MORE GENERAL USE OF THE NARCOTIC ANTAGONISTS, THE AUTHORS PARTICIPATED IN A LONG-TERM OBJECTIVE EVALUATION OF A COMMUNITY-BASED ABSTINENCE PROGRAM FOR ADDICTS PAROLED FROM CORRECTIONAL INSTITUTIONS WITHIN THE STATE OF MARYLAND. THIS EVALUATION AFFORDED EXTENSIVE CLINICAL EXPERIENCE WITH THE OPIATE ABUSER IN A PROGRAM INCORPORATING WEEKLY GROUP PSYCHOTHERAPY, A HIGH LEVEL OF PAROLE SUPERVISION, AND DAILY URINE MONITORING. A SERIES OF STUDIES WAS UNDERTAKEN IN THIS SETTING TO EXPLORE THE EFFICACY OF THE ADMINISTRATION OF NARCOTIC ANTAGONISTS ON A DAILY AND 'CONTINGENT' (UPON EVIDENCE OF NARCOTIC DRUG USE) BASIS. IT WAS FOUND THAT EVEN THE ADDICT'S KNOWLEDGE THAT AN ANTAGONIST WILL ADMINISTERED IF HE OR SHE DEVIATES FROM ABSTINENCE HAD A DETERRENT EFFECT. TWO CONSISTENT RESPONSES TO NARCOTIC ANTAGONISTS WERE NOTED: A SLIGHT, THOUGH REPEATEDLY DISCERNABLE, DECREASE IN NARCOTIC DRUG USE; AND MANEUVERING TO AVOID MEDICATION, EITHER INTERMITTENTLY OR PERMANENTLY. THE FINDINGS SUGGESTED A RELATIONSHIP BETWEEN AVOIDANCE, OR REFUSAL, OF MEDICATION AND THE NARCOTIC BLOCKING CAPABILITY OF THE ACTIVE AGENT. IT IS CONCLUDED THAT MOTIVATION IS A KEY DETERMINANT IN THE SUCCESS OF THE ANTAGONIST APPROACH WITH THE ADDICT PAROLEE. IT IS PROPOSED THAT DRUG-ASSISTED PSYCHOTHERAPY AND ANTAGONIST DRUGS BE EMPLOYED IN A COMBINATION TREATMENT IN ORDER TO EFFECT PERSONALITY CHANGE AND SYMPTOM CONTROL. THE ANTAGONIST TREATMENT ALONE IS CONSIDERED, FOR THE MAJORITY OF PAROLEES, A TECHNIQUE REQUIRING MORE PERSONAL RESPONSIBILITY AND MOTIVATION THAN IS GENERALLY POSSESSED. REFERENCES ARE INCLUDED. (RCB)