There is a lack of research on the possible contribution of a structured risk assessment to the reduction of aggression in psychiatric in-patient care. To assess whether such risk assessments decrease the incidence of violence and coercion. A cluster randomised controlled trial was conducted with 14 acute psychiatric admission wards as the units of randomisation, including a preference arm. The intervention comprised a standardised risk assessment following admission with mandatory evaluation of prevention in high-risk patients. Incidence rates decreased substantially in the intervention wards, whereas little change occurred in the control wards. The adjusted risk ratios suggest a 41% reduction in severe aggressive incidents and a 27% decline in the use of coercive measures. The severity of aggressive incidents did not decrease. Structured risk assessment during the first days of treatment may contribute to reduced violence and coercion in acute psychiatric wards.
