Time from the Admission as the Predictor of Aggressive Behavior of Inpatients with Schizophrenia Spectrum Disorder.

The aim was to assess the incidence of aggressive events (AE) committed by patients diagnosed with schizophrenia spectrum disorethder (SSD) after the first 7 days of hospitalization in psychiatric institution, in comparison to other psychiatric patients. This retrospective cohort study was performed at Psychiatric Hospital "Sveti Ivan", Zagreb, Croatia, using hospital safety records of all patients admitted between 2015 and 2017. Primary outcome was the proportion of patients who committed AE more than a week after the admission to the hospital. Secondary outcome was the time in days from admission to the first incident of AE. The primary analysis was performed using a multivariable binary logistic regression. SSD patients committed AE more often than other patients (incidence rate ratio 3.97 (95% CI 2.35-6.69; p < 0.001; FDR q = 0.002), but these occurred earlier in the course of hospitalization: median (IQR) 2 (1-10) days from admission compared to 11 (2-32) days in other patients. SSD patients had significantly and clinically relevantly lower odds for AE after the first week of hospitalization adjusted for the large number of pre-planned possible confounders (OR = 0.10; 95% CI 0.02-0.45; p = 0.003; FDR q = 0.002). SSD patients seem to express more aggression earlier in the course of hospitalization. Findings of this study indicate that hospitalization-inherent AE risk factors may play an important role in the etiology of AE and inpatients aggressive behavior. Their possible moderating effect should be included in risk-assessment instruments.