RHESUS INCOMPATIBILITY AS A RISK FACTOR FOR SCHIZOPHRENIA IN MALE-ADULTS

Background: Rhesus (Ph) incompatibility is a cause of hemolytic diseas e of the fetus and newborn. Hemolytic disease results from the transpl acentally transmitted maternal antibodies against Rh factor D and can cause permanent neurological damage in the affected newborn. This stud y examines the hypothesis that Rh incompatibility may be a risk factor for schizophrenia. Methods: A sample of 1867 male subjects was divide d into two groups, 535 Rh incompatible and 1332 Rh compatible, and com pared on rate of schizophrenia. Results: The rate of schizophrenia was significantly higher in the Rh-incompatible group (2.1%) compared wit h the Ph-compatible group (0.8%) (P<.03). In addition, since the risk for Ph hemolytic disease increases with second and later Rh incompatib le pregnancies, it is noteworthy that the second- and later-born incom patible offspring exhibited a significantly higher rate of schizophren ia than second- and later-born compatible offspring (P<.05). Also, as predicted, the rate of schizophrenia among firstborn incompatible subj ects was not significantly different from that of firstborn compatible subjects (1.1% vs 0.7%). Conclusion: Ph incompatibility may be a risk factor for schizophrenia.