Verbal and non-verbal behavior immediately prior to aggression by mentally disordered people: enhancing the assessment of risk.

In this study we seek to enhance the assessment of imminent violence risk by providing empirical data on the types of verbal and non-verbal behaviour exhibited by 31 psychiatric inpatients immediately prior to assaulting a staff member, and 31 non-aggressive controls. Verbal abuse, high overall activity level and standing uncomfortably close to the intended victim were the most common behaviours immediately prior to the assault, but most preassault behaviours were also exhibited when patients were not assaulting staff. In the 3 days prior to the assault, aggressive patients differed from non-aggressors in terms of verbal abuse, abnormal activity level (P < 0.05), threatening gestures and threatening stance (P < 0.01). Only one patient was aggressive in the absence of any predictive behaviours. We conclude that most patients exhibit easily identifiable signs of imminent aggression, but that many of these signs occur in the absence of aggression.