Sweden court-orders 350 mentally disordered offenders to forensic psychiatric care yearly. 80% of patients deemed high-risk for severe criminal recidivism due to mental disorder. Patients under special court supervision average 5 years 9 months hospital stay. Patients without supervision average 1 year 9 months stay. Schizophrenia and delusional disorder patients stay longer than those with affective disorders. Forensic psychiatry detains patients indefinitely without court approval for discharge. Forensic settings show higher violence rates than general psychiatry. Few patients commit most aggressive acts. Aggression primarily targets nursing staff then fellow patients. Absconding rates reach 12.6 per 100 patients in psychiatry. Minority of absconders cause most incidents with 16% serious harm. Substance abuse boosts violence risk in mentally ill offenders. Substance abuse plus medication noncompliance strongly predicts violence. 28% criminal recidivism rate during treatment per prior reports. Study examines length of stay and adverse events in full population cohort. High-risk patients compared to low-risk for treatment differences.