Ward crowding and incidents of violence on an acute psychiatric inpatient unit

Objective: Violence in psychiatric wards is common, and it is on the rise. This study examined the relationship between ward occupancy level and staff -to-patient: ratio and incidents of aggressive behavior, both physical and verbal, on an acute inpatient unit in rural New Zealand, Methods: Logistic regression was used to analyze data collected from the wa rd's log of adverse incidents and the ward census over a le-month period. A physical incident was defined as an unwelcome physical contact or willful damage to property, Incidents of self-harm were excluded. Verbal aggression was any threat of physical or sexual harm. Results: Among 381 admissions during the study period, 58 incidents were re corded-25 incidents of verbal aggression and 33 incidents of physical viole nce. Logistic regression demonstrated that the occupancy level was positive ly associated with the occurrence of any type of violent incident. The aver age occupancy level when an incident occurred was 77 percent, compared with 69 percent when no incidents occurred. The average occupancy level was sig nificantly higher when verbal incidents occurred (80 percent) than when phy sical incidents occurred (70 percent). No association was found between vio lence and staff-to-patient ratio. Incidents were significantly more likely to occur during the afternoon shifts (3 p.m. to 11 p.m,), Conclusions: Crowding was found to be significantly associated with aggress ive incidents, and in particular with verbal aggression.