Incidents of aggression in German psychiatric hospitals: Is there an increase?

Introduction: In a meta-analysis of international studies, 17% of admitted patients in psychiatric hospitals had shown violent behaviour towards others. Reported data from studies in Germany were considerably lower until now. However, studies referred to single hospitals and data quality was questionable. It is under discussion whether there is an increase of violent incidents. Methods: In a group of 10 hospitals serving about half of the population of the Federal State of Baden-Wuerttemberg with 11 million inhabitants, the staff observation aggression scale, revised (SOAS-R) was introduced into the electronic charts as part of routine documentation. Data recording was strongly supported by staff councils and unions. Complete data is now available for the year 2019. For one hospital, data is available since 2006. Due to some doubts with respect to fully covering self-directed aggression, we restricted the analysis to aggression toward others and toward objects. Results: In 2019, 17,599 aggressive incidents were recorded in 64,367 admissions (1,660 staying forensic psychiatric patients included). 5,084 (7.90%) of the admitted cases showed aggressive behaviour towards others. Variation between hospitals was low to modest (SD=1.50). The mean SOAS-R score was 11.8 (SD between hospitals 1.20 %). 23% of the incidents resulted in bodily harm. The percentage of patients with violent behaviour was highest among patients with organic disorders (ICD-10 F0) and lowest among patients with addictive or affective disorders (F1, F3, F4). Forensic psychiatry had the highest proportion of cases with aggressive behaviour (20.54 %), but the number of incidents per bed was lower than in general adult psychiatry and child and adolescent psychiatry, indicating a lower risk for staff. In the hospital with long-time recordings available, an increase could be observed since 2010, with considerable variation between years. Conclusion: This is the most robust estimate of the frequency of violent incidents in German psychiatric hospitals so far. The incidence is about half of what has been reported internationally, probably due to sample selection bias in previous studies and a relatively high number of hospital beds in Germany. Available data suggests an increase in violent incidents over the last ten years; however, it is unclear to what extent this is due to increased reporting.