ABSTRACT
OBJECTIVE: This study was designed to identify the role of serotonin and cortisol in the pathophysiology of schizophrenia by measuring quantitative change of serum cortisol levels after risperidone(5HT2 antagonist) administration. METHOD: Subjects included 10 male and 7 female patients who met DSM-IV criteria for schizophrenia(n=17). Blood samples(4ml/sample) were taken at the baseline, 1st, 2nd, 3rd, 14th, 28th and 42nd days, twice, at 8:00 AM and at 10:00 AM in the morning after an overnight fast. The daily medication was administered after the first blood sampling at 8:00 AM. After baseline sampling, the same dose of risperidone was administered to each patient until the end of the 3rd day. The dose of risperidone was then decided by clinical evaluation. Serum cortisol concentrations were measured by standard double-antibody radioimmunoassay. RESULT: 1) Administration of risperidone significantly decreased serum cortisol levels(p<0.05). 2) There were significant reductions in positive symtom scores(21.7+/-3.8, vs 14.3+/-4.1) and negative symptom scores(20.5+/-5.2, vs 15.2+/-3.2), general symptom scores(44.3+/-5.4, vs 32.9+/-4.2) of PANSS after risperidone administration(p<0.05). 3) There were no significant differences in baseline serum cortisol levels and the reductions of serum cortisol levels after administration of risperidone between males and females. 4) There were no significant differences in baseline serum cortisol levels and the reductions of serum cortisol levels after administration of risperidone between positive symptom subgroup and negative symptom subgroup. CONCLUSION: These results suggest risperidone decreases serum cortisol levels in s chizophrenic patients and the reduction of cortisol by risperidone administration might be important factor in the treatment of schzophrenics, in contrast with typical antipsychotics.