Relationship between First-Episode Schizophrenic Psychopathology and 99m-Tc-ECD SPECT Regional Cerebral Blood Flow and Plasma Homovanillic Acid / 대한정신약물학회지

OBJECTIVE: The purpose of this study was to examine the relative blood flow differences of brain regions between first-episode schizophrenic patients and normal controls and the relationships between these regions and the changes of psychopathology scores, the treatment response, after serotonin dopamine antagonist (SDA) risperidone treatment. Another purpose of this study was to investigate SPECT relative blood flow index as the treatment response predictor of SDA treatment under control of the influences of homovanillic acid (HVA). We hypothesize that there is differences in the brain blood flows examined by SPECT between first-episode schizophrenic patients and normal controls. Relative blood flow index examined by SPECT will be the response predictors of SDA treatment of schizophrenia under control of influences of metabolites. METHODS: The relative blood flows of seventeen first-episode schizophrenic patients and ten normal controls were examined by 99m-Tc ECD SPECT before drug treatment. The patients group was treated for 6 weeks with SDA. The psychopathology was assessed at baseline just before SDA trial and then at 2 weeks and 6 weeks after SDA treatment. At the same time plasma HVA was evaluated by HPLC (high performance liquid chromatography). RESULTS: The cerebral blood flow of first-episode schizophrenic patients was decreased in thalamus and left basal ganglia and the relative blood flow index of schizophrenic patient's left thalamus was significant therapeutic predictor of SDA treatment of positive symptoms under control of the HVA influnences. CONCLUSION: These results suggest that the relative blood flow examined by SPECT will be a therapeutic index of SDA treatment in schizophrenia.

Role of Serotonin in Pathophysiology and Treatment of Schizophrenia

There is no doubt that dopamine plays a critical role in the etiopathogenesis of schizophrenia. However, there appeared some limitations in explaining the complex phenomena of schizophrenia. Recent research data suggest that dysfunction in serotonergic system may be involved Before the dopamine hypothesis of schizophrenia became established, the interest in serotonin(5-ydroxytryptamine, 5-HT) as an etiological substrate of this illness occurred. Recently the importance and extent of 5-HT's involvement in the pathophysiology and mechanism of action of antipsychotic drug is actively investigated. In recent years, therapeutic success of clozapine and risperidones has increased attention on the interaction between the 5-HT and dopamine systems in schizophrenia. This led to the serotonin-dopamine for antipsychotic. The authors review the evidence for the role of 5-HT in schizophrenia and serotonin-dopamine interaction.