OF THE 62 CASES CLASSIFIED AS VIOLENT BY BRONX, N.Y., MUNICIPAL HOSPITAL CENTER THE EMERGENCY ROOM CLINICIAN OVER A 2-WEEK PERIOD, 42 HAD ACTED OUT VIOLENT IMPULSES PRIOR TO THEIR EMERGENCY ROOM VISITS. ON INTERVIEW, 29 OF THESE 42 PATIENTS DENIED ANY DEGREE OF PREMEDITATION OR CONSIDERATION OF VIOLENCE PRIOR TO ACTING OUT; ONLY 13 ADMITTED THAT THEY HAD HAD PRIOR HOSTILE THOUGHTS OR INTENTIONS. THIRTY-THREE OF THE SIXTY-TWO PATIENTS EXPRESSED AGGRESSIVE IDEATION. THUS, IN 20 PATIENTS THE OPEN RECOGNITION AND EXPRESSION OF FEELINGS WAS UNACCOMPANIED BY VIOLENT BEHAVIOR. THE MAJORITY (64 PERCENT) OF THE VIOLENT ACTS RESULTING IN VISITS WERE CASES OF SIMPLE ASSAULT (I.E., FIGHTING); 26 PERCENT INVOLVED INCIDENTS WITH KNIVES, AND THE REMAINING 10 PERCENT REPRESENTED VARIOUS POTENTIALLY LETHAL ACTS WITHOUT WEAPONS. NONE OF THE EMERGENCY ROOM PATIENTS HAD USED FIREARMS. ALTHOUGH THE LIKELIHOOD OF FUTURE VIOLENT ACTS COULD NOT BE PREDICTED ACCURATELY, THE AUTHORS DISCOVERED THAT A SIGNIFICANT MAJORITY OF VIOLENT PATIENTS WERE POTENTIALLY TREATABLE WITHIN THE SETTING OF EMERGENCY PSYCHIATRY PRACTICE. COMPONENTS, STUDY RESULTS, AND IMPLICATIONS FOR INTERVENTION ARE SUMMARIZED. SIGNIFICANT TABULAR DATA ARE PROVIDED. FOR THE COMPLETE REPORT, SEE NCJ-45072. (DAS)