A STATISTICAL STUDY OF THE ETIOLOGY OF VIOLENCE IN 30 SUBJECTS, ALL NONPSYCHOTIC AND RANGING FROM 13 TO 45 YEARS OF AGE, WAS CONDUCTED TO SEE IF THEY COULD BE DIVIDED INTO GROUPS FOR PURPOSES OF THERAPY OR OTHER PREVENTION. SEVERITY OF THREE PSYCHOSOCIAL AND ORGANIC MORBIDITY CATEGORIES, RATED ON A SCALE OF FOUR POINTS, WAS CROSS-CORRELATED WITH 14 DOCUMENTABLE CHARACTERISTICS ASSOCIATED WITH THE VIOLENCE. THE MANN-WHITNEY U TEST WAS USED TO DETERMINE STATISTICAL SIGNIFICANCE AT P LESS THAN OR EQUAL TO 0.05. THE GROUPING SHOWED THAT THREE OF THE PATIENTS HAD VIOLENT EPISODES ON ONLY ONE OR TWO OCCASIONS, HAD SIGNIFICANTLY LOW PSYCHOSOCIAL AND ORGANIC MORBIDITY SCORES, AND WERE SIGNIFICANTLY INFLUENCED ONLY BY SEVERE PROVOCATION. FIVE OF THE PATIENTS BECAME VIOLENT ONLY UNDER THE INFLUENCE OF ALCOHOL. FOUR OF THESE HAD SIGNIFICANTLY LOW ORGANIC MORBIDITY, AND ONE HAD PATHOLOGICAL INTOXICATION AND AN ORGANIC MORBIDITY SIMILAR TO THOSE OUTSIDE THE ALCOHOL GROUP, PLUS A FOCAL ABNORMALITY OF THE EEG. THREE WERE ALWAYS INTOXICATED AT THE TIME OF VIOLENCE. CONSIDERING THE INFLUENCE OF ALCOHOL ON THE OTHER GROUPS, IT APPEARS THAT ALCOHOL IN COMBINATION WITH PSYCHOSOCIAL MORBIDITY BEHAVES AS IF IT WERE AN ORGANIC MORBIDITY FACTOR. IN THE LARGEST GROUP OF 22 PATIENTS, 4 HAD HIGH PSYCHOSOCIAL MORBIDITY SCORES AND LOW ORGANIC MORBIDITY SCORES, 8 HAD THE OPPOSITE COMBINATION, AND 10 HAD SCORES SIGNIFICANTLY WEIGHTED TO BOTH SCALES. EPILEPTIC AURAS, REDUCED CONSCIOUSNESS DURING THE EPISODE, SLEEP OR CONFUSION AFTER THE EPISODE, AND POSSIBLY LACK OF WARNING ANGER WERE SIGNIFICANTLY RELATED TO ORGANIC MORBIDITY. SEVERE VIOLENCE, EPISODES LASTING OVER 30 MINUTES, AND GUILT AFTERWARDS WERE SIGNIFICANTLY ASSOCIATED WITH PSYCHOSOCIAL MORBIDITY. STATISTICAL TABLES AND REFERENCES ARE INCLUDED. (AUTHOR ABSTRACT MODIFIED--TWB)