만성정신분열증 환자에서 우측 전두엽 전부 백질의 양성자 대사물질 변화

Alteration of Proton Metabolites of the Right Prefrontal White Matter in Chronic Schizophrenics

Objects : Magnetic resonance spectroscopy is being used to survey functional activity throughout the brain and thus bring together the disparate lines of neurochemical, neuroanatomical approaches to various psychiatric illness. The most frequently reported morphometric changes in schizophrenia are in ventricle and temporolimbic tissue. Other abnormalitis reported are sulcal enlargement and alterations in whole-brain gray matter frontal lobes, subcortical structures, corpus callosum, and cerebellum. With these aspects in mind, this study was designed to test the so-called ‘hypofrontality’ hypothesis, one of pathophysiology in schizophrenia in terms of neurochemical aspects. Methods : The subjects consisted of 16 hospitalized patients who fulfilled criteria for chronic schizophrenia by DSM-IIIR-R. All subjects were further interviewed to rate the severity of clinical symptoms on Brief Psychiatric Rating Scale(BPRS), and Positive and Negative Syndrome Scale(PANSS). All were examined with localized in vivo M R spectroscopy in right prefronal white matter to measure proton metabolites and their change possibly associated with treatment. Results : The results were as follows : 1) The spectral features of some distinct proton metabolites such as NAA, Cr, Cho, Glu, G A B A were clearly identified in both schizophrenics and healthy controls. 2) The mean signal intensity ratios of proton metabolites were 1.17±0.23 for Cr/Cho, 1.48± 0. 24, for NAA/Cho, 1.29± 0.19 for NAA/Cr, 0.32± 0.18 for Glu/NAA, 0.63± 0.20 for GABA/NAA, 0.94±0.32 for GABA/Cho, and 0.78±0.21 for GABA/Cr, respectively in schizophrenics. The schizophrenics had significantly higher ratios of Cr/Cho, GABA/NAA, GABA/Cho, and GABA/Cr compared to controls(P=0.002, P = 0.0022, P = 0.001, P=: 0.033). Those were 0.89士 0.14， 0.38± 0.14, 0.53± 0.21，0.60± 0.21, respectively in normal controls. However, a significant decrease in NAA/Cr ratio was found in schizophrenics(P=0.017). 3) The correlation between the signal intensity ratio of proton metabolites and symptom severity rated by BPRS showed that the higher were the BPRS scores, the higher was the ratio of GABA /C ho(P =0.05, P = 0.027). However increased ratio of NAA/Cr was correlated with decrease of BPRS scores(P: ᅳ 0.68, P = 0.004). 4) The increase of NAA/Cr ratio was correlated with the decrease of negative symptoms assessed by PANSS (P = —0.55, P = 0.029). Conclusion : In light of our results, it seems likely that the decrease of NAA/Cho ratio which would be closely associated with neuronal damage supports the hypofrontality hypothesis, and clinical symptoms would be related to the change of GABA.