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

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 schizophrenic patients. The present study was conducted to determine the frequency of Gilbert's syndrome in schizophrenic patients relative to patients with other psychiatric disorders.

Plasma bilirubin concentrations of every patient admitted to the psychiatric hospital during a 3-year period were collected, and patients were examined to exclude all other causes of hyperbilirubinemia. In addition, the psychiatric symptoms of schizophrenic patients (ICD-10 criteria) with hyperbilirubinemia were evaluated by the Positive and Negative Syndrome Scale (PANSS).

Schizophrenic patients showed a significantly higher incidence of hyperbilirubinemia (p < .05) relative to patients suffering from other psychiatric disorders, and schizophrenic patients with hyperbilirubinemia showed significantly higher scores on the positive and general psychiatric subscales of the PANSS (p < .0001) than patients without hyperbilirubinemia.

The apparently higher frequency of Gilbert's syndrome in schizophrenic patients may reflect a relationship between hyperbilirubinemia and schizophrenic psychosis. Hypothetical explanations, such as a possible genetic disposition for Gilbert's syndrome, an increased vulnerability of red cell membranes, and the role of estrogens in schizophrenic patients, are discussed.