Seasonal variation of hospital violence, seclusion and restraint in a forensic psychiatric hospital.

Several epidemiological studies have reported seasonal patterns in both violent and self-destructive behaviour. However, a few studies on hospital violence have found contradictory results. The aim of this study was to investigate whether there was any seasonal variation of violence in a forensic psychiatric hospital providing care for persons suffering from psychotic disorders and violent or self-destructive behaviour. Seasonal variation of the prevalence of seclusion and restraint was also investigated. Reports of violent incidents and seclusion and restraint statistics from between 2007 and 2012 were examined with Poisson regression analysis. There was significant variation in the prevalence of seclusion and restraint between months (p<0.001), and between seasons (p<0.001). Monthly prevalence of seclusion and restraint was the lowest in January compared to other months. In comparison, the prevalence of seclusion and restraint was lower in winter than in other seasons. In a hospital with persons suffering from psychotic disorders, no significant variation of violence or self-destructive behaviour was found, similarly as in the society. By contrast, the prevalence of seclusion and restraint showed marked seasonality. Variation in the prevalence of seclusion and restraint was not consistent with the variance in violence, which implies that the use of coercive measures is related to seasonal variation among staff.