THREE CATEGORIES OF FINDINGS ARE DISCUSSED: (1) OPINIONS EXPRESSED BY USERS AND NONUSERS REGARDING SUCH RELATIONSHIPS, (2) INCIDENCES OF RECORDED OFFENSES BY USERS AND NONUSERS, AND (3) PERSONALITY CHARACTERISTICS THOUGHT TO FACILITATE CRIMINAL BEHAVIOR. RESULTS WERE OBTAINED FROM TWO LARGE STUDIES ON TWO GROUPS: 204 USERS AND 115 NONUSERS ALL OF WHOM WERE FREE CITIZENS, AND 850 USERS AND 839 NONUSERS WHO WERE PRISON INMATES. FINDINGS WERE OBTAINED AS PART OF A PROJECT FOR THE STUDY OF CHRONIC CANNABIS CONSUMPTION IN EGYPT. STANDARDIZED QUESTIONS WERE ADMINISTERED TO THE SUBJECTS. MORE OF THE CONTROL GROUPS EXPRESSED THE OPINION THAT USERS HAD CRIMINAL TENDENCIES AND COMMITTED MORE OFFENSES THAN NONUSERS. THE SAME PROFILE OF RESPONSES WAS GIVEN BY PRISON INMATES AS WELL AS NONPRISON SUBJECTS. WITHIN THE USER GROUPS, DIFFERENCES BETWEEN THOSE WHO TOOK OPIUM AND THOSE WHO TOOK CANNIBIS WERE FOUND TO BE INSIGNIFICANT. AMONG 553 USERS AND 458 CONTROLS, ALL PRISON INMATES, SIGNIFICANTLY MORE CONTROLS THAN USERS, WERE FOUND TO HAVE CRIMINAL RECORDS PREVIOUS TO THEIR ARREST. CANNABIS USERS TENDED TO BE LESS QUARRELSOME THAN NONUSERS. IN CULTURALLY STRESSFUL SITUATIONS, USERS HAD DEVELOPED WAYS OF NOT PROVOKING SUPERIORS TO AGGRESSIVE BEHAVIOR, BUT IF SUCH TACTICS FAILED, USERS WOULD REACT MORE AGGRESSIVELY THAN THE CONTROL GROUP. WHEN FACED WITH TEMPTATIONS FOR CHEATING OR FOR EVADING RESPONSIBILITY, USERS WOULD BEHAVE IN A MORALLY UNSOUND WAY COMPARED WITH CONTROLS. WHEN DEPRIVED OF THE DRUG, USERS WERE FOUND TO UNDERGO MOOD MODIFICATIONS THAT WOULD MAKE THEM ILL-TEMPERED, MORE IMPULSIVE, AND QUARRELSOME. TABLES ARE INCLUDED. (AUTHOR ABSTRACT)