The differential effect of the menstrual cycle on psychiatric emergencies was assessed by evaluating a representative female sample of emergency room psychiatric patients intermittently over a one-year period. The results showed that the menstrual cycle has a differential effect that is manifested by the type of psychiatric emergencies the women appear with; specifically, nonpsychotic menstruating women with more severe past medical and gvnecologic histories who have more sexual and marital problems appear to be more susceptible to a premenstrual psychiatric emergency characterized by hostility, suicidal ideation, and an actual suicide attempt.Abstract Teaser