Schizophrenia-Associated Idiopathic Unconjugated Hyperbilirubinemia (Gilbert's Syndrome).

Background: Idiopathic unconjugatedhyperbilirubinemia (Gilbert’s syndrome) is a benignhyperbilirubinemia found in the general population. There hasbeen only 1 previous report of Gilbert’s syndrome occurring inschizophrenic patients. The present study was conducted todetermine the frequency of Gilbert’s syndrome in schizophrenicpatients relative to patients with other psychiatric disorders.

Method: Plasma bilirubin concentrations of everypatient admitted to the psychiatric hospital during a 3-yearperiod were collected, and patients were examined to exclude allother causes of hyperbilirubinemia. In addition, the psychiatricsymptoms of schizophrenic patients (ICD-10 criteria) withhyperbilirubinemia were evaluated by the Positive and NegativeSyndrome Scale (PANSS).

Results: Schizophrenic patients showed asignificantly higher incidence of hyperbilirubinemia (p < .05)relative to patients suffering from other psychiatric disorders,and schizophrenic patients with hyperbilirubinemia showedsignificantly higher scores on the positive and generalpsychiatric subscales of the PANSS (p < .0001) than patientswithout hyperbilirubinemia.

Conclusion: The apparently higher frequency ofGilbert’s syndrome in schizophrenic patients may reflect arelationship between hyperbilirubinemia and schizophrenicpsychosis. Hypothetical explanations, such as a possible geneticdisposition for Gilbert’s syndrome, an increased vulnerability ofred cell membranes, and the role of estrogens in schizophrenicpatients, are discussed.