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.