The relationship between ABO blood group and schizophrenia: An analysis based on a Chinese survey

This study investigates the distribution characteristics of ABO blood groups among patients with schizophrenia and normal people. A retrospective analysis was conducted on the clinical data of 6772 psychiatric patients in Wuxi from January 2003 to December 2025. A control group comprising 871 healthy individuals undergoing routine medical examinations during the same period was established to analyze differences in ABO blood group distribution between the two groups. Among schizophrenia patients, blood types A, AB, B, and O were present in 2599, 574, 1646, and 1953 cases respectively, totaling 6772 cases. Their proportions were 38.4%, 8.5%, 24.3%, and 28.8%. Among the healthy controls, blood types A, AB, B, and O were present in 277, 85, 252, and 25 individuals respectively, totaling 871 cases, representing proportions of 31.8%, 9.8%, 28.9%, and 29.5%. Firth logistic regression after adjusting for factors such as age, gender, and marital status still revealed statistically significant differences in ABO blood group distribution between schizophrenia patients and healthy controls, with a higher proportion of type A blood and a lower proportion of type B blood in the schizophrenia group compared to the healthy population. The proportion of type A blood in patients with schizophrenia is higher than that in the general population, while the proportion of type B blood is lower than that in the general population.