Abstract: Objective To provide reference for medical and health services and forensic expertise, the causes and manners of death of psychiatric patients were analyzed retrospectively. Methods A total of 105 autopsy cases of psychiatric patients accepted and settled by Institute of Forensic Science of Criminal Investigation Police University of China from 2004 to 2019 were collected. The cases were divided into four groups： disease death, suicidal death, accidental death and homicidal death. The common causes of death of each group were statistically analyzed and the differences in age, disease duration, body mass index（BMI）and gender among the groups were assessed. Results Of the 105 cases, 60 were male and 45 were female, the course of psychosis was （12.9±10.4） years, the age of the deceased was （51.3 ± 11.4） years, and 61.0% was schizophrenic. There were 50 cases （47.6%） in the disease death group, in which the psychiatric patients were the oldest and had the longest course of psychosis and lowest BMI. Pulmonary thromboembolism, respiratory infections, and cardiogenic disease were the most common causes of death in the group. There were 26 accidental deaths （24.8%）, among which traffic accidents were the most common cause of death. There were 15 homicidal deaths （14.3%）, all of which were male, with craniocerebral injury being the most common cause of death. There were 14 suicidal deaths （13.3%）. In suicidal death group, the age of the deceased was the youngest, the course of psychosis was the shortest and falling from the height was the most common way to commit suicide. Conclusion Understanding the common causes of death of psychiatric patients may contribute to developing measures to reduce the mortality rate of the population. It is necessary to investigate the age, course of psychosis and gender of the deceased when assessing the manner of death.

Key words: forensic pathology, forensic psychiatry, mentally ill persons, autopsy, cause of death, manner of death, cases analysis