Blood groups and affective disorders

Frequencies of ABO, Rh, MNSs, P, Kell, Lewis and Duffy blood groups were studied in a total of 219 patients with affective disorders. The patients were classified into four groups: (1) bipolar (manic-depressive) psychosis; (2) unipolar recurrent depressive psychosis; (3) nonpsychotic 'reactive' depression, and (4) 'unclassifiable'. The following statistically significant results were found: an increased frequency of the blood group factor B among psychotic (bipolar and unipolar) patients compared to nonpsychotic patients, a decreased frequency of the SS phenotype in the unclassifiable group and an increased frequency of the K(+) phenotype among the nonpsychotic patients. Previous results concerning differences between bipolar and unipolar patients with respect to the A and O blood types were not confirmed in this investigation.