ACCORDING TO AN ENGLISH STUDY OF 78 MURDER-SUICIDE CASES OCCURRING IN THE COUNTRY BETWEEN 1954 AND 1961, SUICIDE OR ATTEMPTED SUICIDE FOLLOWING MURDER OCCURS IN 30 PERCENT OF ALL HOMICIDE CASES, USUALLY INVOLVES PERSONS IN MIDDLE OR UPPER CLASS INCOME BRACKETS, AND OFTEN TAKES PLACE AMONG FAMILY MEMBERS. THE MURDERS ARE USUALLY COMMITTED BY GAS POISONING, OR SHOOTING (69 PERCENT), AND THE ACTIVITY USUALLY TAKES PLACE AT NIGHT DURING THE BEGINNING OF THE WEEK. THE VICTIMS ARE USUALLY CHILDREN UNDER THE AGE OF 16. ABOUT 57 PERCENT OF THE MURDERERS HAD HISTORIES OF MENTAL ILLNESS, MOST HAD NO PRIOR CONVICTION RECORD, AND MOST WERE MARRIED. THE STUDY INDICATED THAT FEELINGS OF DESPAIR IN THE ELDERLY ILL, IMPULSIVE AGGRESSION IN YOUNG PEOPLE INVOLVED IN FRUSTRATING LOVE AFFAIRS, AND INABILITY TO COPE WITH DECEIT IN FINANCIAL OR SEXUAL AFFAIRS WERE CONTRIBUTING FACTORS. THE CENTRAL PSYCHOPATHOLOGY WAS MELANCHOLIC DEPRESSION. STUDIES OF MURDER-SUICIDE INCIDENTS IN THE UNITED STATES SHOW THAT THE ACTORS MORE OFTEN WERE SCHIZOPHRENIC MALES AND THE VICTIMS WERE OLDER, OFTEN THE WIVES OF THE MURDERERS. IN THE U.S. SUICIDE FOLLOWS HOMICIDE IN ONLY 5 PERCENT OF ALL HOMICIDE CASES, BUT THERE IS A GREATER SUICIDE RATE IN U.S. JAILS AND PRISONS THAN IN BRITISH PRISONS. THE U.S. MURDER-SUICIDE INCIDENTS ALSO DISPLAY MORE VIOLENCE THAN THE ENGLISH CASES. RESEARCHERS AND THEORISTS HAVE ATTEMPTED TO UNDERSTAND THE DYNAMICS SURROUNDING MURDER-SUICIDE INCIDENTS. THESE OFTEN INVOLVE A CLOSE EMOTIONAL RELATIONSHIP BETWEEN THE ACTOR AND THE VICTIM; THE ACTOR IS OFTEN AFRAID OF KILLING HIMSELF AND, THEREFORE, KILLS SOMEONE ELSE, AND POSSESSIVE FEELINGS ON THE PART OF MOTHERS PLANNING SUICIDE SOMETIMES RESULT IN CHILD MURDER. PREVENTION MAY BE ACCOMPLISHED THROUGH EFFECTIVE ASSESSMENT AND FOLLOWUP OF PERSONS CONTACTED BY POLICE AND MENTAL HEALTH PERSONNEL AS A RESULT OF HOMICIDAL THREATS. TREATMENT CAN INCLUDE FAMILY INTERVIEWS, TELEPHONE CONTACTS, PRESCRIPTIONS FOR TRANQUILIZERS, HOSPITALIZATION, AND EMERGENCY INTERVENTION METHODS. REFERENCES ARE PROVIDED. (DAG)