Schizophrenia-associated idiopathic unconjugated hyperbilirubinemia (Gilbert's syndrome)

Background: Idiopathic unconjugated hyperbilirubinemia (Gilbert's syndrome) is a benign hyperbilirubinemia found in the general population. There has been only 1 previous report of Gilbert's syndrome occurring in schizophreni c patients. The present study was conducted to determine the frequency of G ilbert's syndrome in schizophrenic patients relative to patients with other psychiatric disorders. Method: Plasma bilirubin concentrations of every patient admitted to the ps ychiatric hospital during a 3-year period were collected, and patients were examined to exclude all other causes of hyperbilirubinemia. In addition, t he psychiatric symptoms of schizophrenic patients (ICD-IO criteria) with hy perbilirubinemia were evaluated by the Positive and Negative Syndrome Scale (PANSS). Results: Schizophrenic patients showed a significantly higher incidence of hyperbilirubinemia (p < .05) relative to patients suffering from other psyc hiatric disorders, and schizophrenic patients with hyperbilirubinemia showe d significantly higher scores on the positive and general psychiatric subsc ales of the PANSS (p < .0001) than patients without hyperbilirubinemia. Conclusion: The apparently higher frequency of Gilbert's syndrome in schizo phrenic patients may reflect a relationship between hyperbilirubinemia and schizophrenic psychosis. Hypothetical explanations, such as a possible gene ric disposition for Gilbert's syndrome, an increased vulnerability of red c ell membranes, and the role of estrogens in schizophrenic patients, are dis cussed.