The current study focuses on the situational antecedents of self-harming behavior & outawardly directed aggression of psychiatric inpatients. Auto-aggression was found to be significantly more prevalent during the evening & reached its highest level between 8 & 9pm. The majority of self-harming acts took place in patients’ bedrooms. Outwardly directed aggression was particularly common in day-rooms, staff offices, hallways, & dining rooms. These results suggest that a lack of stimulation & interaction with others increases the risk of self-injurious behavior. (20 refs)