ABO-RH blood groups and psychiatric diagnosis: a critical review

The authors studied 312 consecutive admissions to a psychiatric service for a relationship of the ABO - Rh blood groups with psychiatric diagnosis. Even though the results were significant, showing an increase of A blood group with M.D.D. and O group with Sch, the authors observe that the general patient population was skewed and significantly different from the general population of the area. This same observation was made for most of the previous studies that have reported significant correlations between various blood groups and different psychiatric diagnosis. Because of this, the conclusion of the present study is that at the present time positive associational findings of blood groups with psychiatric diagnosis are probably related to a skewed and stratified patient population sample.