THE TWO GROUPS' AGES, EDUCATIONAL LEVELS, AND IQ'S DID NOT DIFFER. MEAN AGE WAS 22.8; EDUCATION, 11.7 YEARS; AND IQ, 101.7. MMPI SCORES WERE OBTAINED FOR 3 VALIDITY AND 10 CLINICAL SCALES. MOST MMPI SCALES WERE FOUND TO BE ELEVATED FOR HEAVY DRUG USERS. A SIGNIFICANTLY LARGER PROPORTION OF DRUG USERS THAN NONUSERS OBTAINED 'T' SCORES EQUAL TO OR GREATER THAN 70 FOR EACH SCALE EXCEPT S, THEREBY SUGGESTING THAT MULTIPLE DRUG USE IS ANOTHER DEVIANT BEHAVIOR FOR INMATES INCARCERATED FOR DRUG-RELATED CRIMES. DRUG USERS HAD SIGNIFICANTLY HIGHER MEAN SCORES FOR SCALES F, D, PA, AND SC. RESULTS SUGGESTED THAT DRUG USERS VIEW THE WORLD DIFFERENTLY FROM NONUSING INMATES IN THAT THEY ARE MORE SENSITIVE TO THE VIEWS OF OTHERS, ARE MORE SUSPICIOUS OF OTHERS' MOTIVES, AND HAVE POORER MORALE. THE PROFILE OF DRUG USERS WAS MOST CONSISTENT WITH A DIAGNOSIS OF PARANOID SCHIZOPHRENIC REACTION. NEXT MOST FREQUENT DIAGNOSIS WAS SOCIOPATHIC PERSONALITY. INTERVIEWS WITH 37 OF THE DRUG USERS DID NOT, HOWEVER, SUPPORT A DIAGNOSIS OF PSYCHOSIS. THIS INDICATED THAT HEAVY DRUG USERS MAY HAVE EXPERIENCED SENSORY PHENOMENA MIMICKING PSYCHOTIC SYMPTOMS AT SOME TIME PREVIOUSLY BUT NOT AT THE TIME OF TESTING. FURTHER RESEARCH ON THIS POSSIBLILITY IS RECOMMENDED. TABLES AND A REFERENCE LIST ARE INCLUDED. (CFW)