THE MMPI (MINNESOTA MULTIPHASIC PERSONALITY INVENTORY) YIELDS A PERSONALITY PROFILE MADE UP OF FOUR VALIDITY AND TEN CLINICAL SCALES. EACH SCALE HAS A NAME AND NUMBER USED WIDELY IN CLINICAL AND RESEARCH LITERATURE. THIS STUDY REFINES WORK DONE WITH JUVENILES IN THE 8-4 AND THE 8-(1,2,7) PERSONALITY GROUPS. REPORTS FROM TEACHERS AND THERAPISTS, BEHAVIOR RATING SCALES, CASE HISTORIES, FAMILY HISTORIES, AND ADDITIONAL PERSONALITY TESTS WERE USED TO IDENTIFY THE CHARACTERISTICS ASSOCIATED WITH EACH GROUP. AS FOUND BY OTHERS, BOYS IN THE 8-4 GROUP HAD A HOSTILE ORIENTATION TOWARD OTHERS, ENGAGED IN ACTIVE VIOLENT BEHAVIOR, AND HAD BEEN REJECTED BY THEIR FAMILIES. THEY HAD GENERALLY HIGHER INTELLIGENCE QUOTIENTS AND DID BETTER IN SCHOOL. THEY WERE MORE LIKELY TO BECOME INVOLVED IN CRIMES OF VIOLENCE. THE BOYS IN THE 8-(1,2,7) GROUP WERE INTROVERTED AND CONFUSED, LASHED OUT AT OTHERS FROM FEELINGS OF INFERIORITY, AND WERE INVOLVED IN DRUG ABUSE, RUNNING AWAY, AND DELINQUENT ACTS INITIATED BY OTHERS. PREVIOUS RESEARCHERS HAVE FOUND SEVERELY DISTURBED FAMILIES, WHILE THIS STUDY FOUND AFFECTIONATE MOTHERS AS HEADS OF THE HOUSEHOLDS THE BOYS SEEM TO DRIFT INTO DELINQUENCY DO TO THE LACK OF A MALE AUTHORITY FIGURE IN THE HOME. THE TREATMENT PROGNOSIS FOR EACH GROUP IS GOOD, BUT THERAPY APPROACHES ARE QUITE DIFFERENT. THE STUDY INSTRUMENTS, THEIR STATISTICAL ANALYSIS, AND REFERENCES ARE APPENDED. (GLR)