Frequency and severity of aggressive incidents in acute psychiatric wards in Switzerland.

Background: Aggression and violence and negative consequences thereof are a major concern in acute psychiatric inpatient care globally. Variations in study designs, settings, populations, and data collection methods render comparisons of the incidence of aggressive behaviour in high risk settings difficult.

Objective: To describe the frequency and severity of aggressive incidents in acute psychiatric wards in the German speaking part of Switzerland.

Methods: We conducted a prospective multicentre study on 24 acute admission wards in 12 psychiatric hospitals in the German speaking part of Switzerland. Aggressive incidents were recorded by the revised Staff Observation Aggression Scale (SOAS-R) and we checked the data collection for underreporting. Our sample comprised 2344 treatment episodes of 2017 patients and a total of 41'560 treatment days.

Results: A total of 760 aggressive incidents were registered. We found incidence rates per 100 treatment days between 0.60 (95% CI 0.10-1.78) for physical attacks and 1.83 (1.70-1.97) for all aggressive incidents (including purely verbal aggression). The mean severity was 8.80 +/- 4.88 points on the 22-point SOAS-R-severity measure; 46% of the purely verbally aggression was classified as severe (>/= 9 pts.). 53% of the aggressive incidents were followed by a coercive measure, mostly seclusion or seclusion accompanied by medication. In 13% of the patients, one ore more incidents were registered, and 6.9% of the patients were involved in one ore more physical attack. Involuntary admission (OR 2.2; 1.6-2.9), longer length of stay (OR 2.7; 2.0-3.8), and a diagnosis of schizophrenia (ICH-10 F2) (OR 2.1; 1.5-2.9) was associated with a higher risk for aggressive incidents, but no such association was found for age and gender. 38% of the incidents were registered within the first 7 days after admission.

Conclusion: Aggressive incidents in acute admission wards are a frequent and serious problem. Due to the study design we consider the incidence rates as robust and representative for acute wards in German speaking Switzerland, and thus useful as reference for comparative and interventional research. Implications for clinical practice include the recommendation to extend the systematic risk assessment beyond the first days after admission. The study confirms the necessity to differentiate between types of aggressive behaviour when reporting and comparing incidence-data.