BOTH DEFENSIVENESS AND HIGH CONTROL IN ANSWERING SUCH INVENTORIES APPEAR TO BE RELATED TO MURDER OR MURDEROUS ATTACKS IN MAXIMUM SECURITY PATIENTS. FOR THE STUDY, 29 INFORMED MALE VOLUNTEERS AGED 18 TO 45 YEARS WERE TESTED 5 TO 6 WEEKS AFTER ADMISSION TO A SECURITY HOSPITAL. CRITERIA FOR SELECTION WERE LACK OF MEDICATION, NO EVIDENCE OF BRAIN DAMAGE OR OTHER RELEVANT ORGANIC DEFECT, AND A WAIS (WECHSLER ADULT INTELLIGENCE SCALE) VERBAL INTELLIGENCE GREATER THAN 80. THE EPQ (EPINEPHRINE QUOTIENT) WAS GIVEN DIRECTLY AFTER PSYCHOPHYSIOLOGICAL TESTING IN THE LABORATORY. CATECHOLAMINE BALANCE WAS CALCULATED AS THE RATIO OF URINARY NOREPINEPHRINE TO EPINEPHRINE EXCRETION DURING STRESSOR ANTICIPATION. THE URINE WAS COLLECTED OVER A 2-HOUR PERIOD PRIOR TO PSYCHOPHYSIOLOGICAL TESTING. THE RESULTS GENERALLY SUPPORTED THE HYPOTHESIS. THOSE SUBJECTS WITH A HIGH CATECHOLAMINE INDEX OF MURDEROUS PROPENSITY TENDED TO GIVE PSYCHOMETRIC INDICATIONS OF DEFENSIVE OVERCONTROL WHICH RELATE TO MURDEROUS PROPENSITY. HIGH QUESTIONNAIRE IMPULSIVITY SCORES ALSO RELATED TO LOW URINE NOREPINEPHRINE AND HIGH EPINEPHRINE EXCRETION. HOWEVER, THE IMPORTANCE OF TEST ENVIRONMENT ON RESPONDING CANNOT BE IGNORED. THESE QUESTIONNAIRES PRESENT A HIGH DEGREE OF ITEM FACE VALIDITY WHICH ALLOWS EASY FAKING. HENCE, SIMPLE-MINDED USE OF QUESTIONNAIRES IN THE SECURITY SETTING COULD LEAD TO CONCLUSIONS REGARDING ANTISOCIAL IMPULSIVE TENDENCIES WHICH ARE QUITE CONTRARY TO REALITY. THE FAKING EXPLANATION APPEARS ADEQUATE AND MORE PARSIMONIOUS THAN THE ANALYTIC ALTERNATIVE WHICH INVOLVES THE CONCEPT OF REPRESSION. IF THIS IS CORRECT, THEN MUCH RESEARCH ON DETAINED OFFENDERS, WHERE PERSONALITY INVENTORY CRITERIA ARE USED TO DEFINE GROUPS SUCH AS PSYCHOPATHS, IS INVALIDATED OR REQUIRES REINTERPRETATION. APPROXIMATELY 15 REFERENCES ARE PROVIDED.