BACKGROUND Abnormally elevated levels of gamma-aminobutyric acid (GABA) in the medial prefrontal cortex (mPFC) have been reported in antipsychotic-free patients with schizophrenia. Whether such GABA elevations are also present in other brain regions and persist after antipsychotic treatment has not been previously investigated. METHODS Twenty-eight antipsychotic-naïve patients with first-episode psychosis (FEP) and 18 healthy control subjects completed the study. Following baseline proton magnetic resonance spectroscopy scans targeting the mPFC and a second region, the dorsal caudate, patients with FEP were treated with oral risperidone for 4 weeks at an initial dose of 1 mg/day that was titrated as necessary based on clinical judgment. After the 4-week treatment period, both groups were brought back to undergo outcome magnetic resonance spectroscopy scans, which were identical to the scans conducted at baseline. RESULTS At baseline, higher GABA levels were found both in the mPFC and in the dorsal caudate of patients with FEP compared with healthy control subjects. Following 4 weeks of antipsychotic treatment, GABA levels in patients with FEP decreased relative to baseline in the mPFC, but decreased only at the trend level relative to baseline in the dorsal caudate. For either brain region, GABA levels at 4 weeks or posttreatment did not differ between patients with FEP and healthy control subjects. CONCLUSIONS The results of the present study documented elevations of GABA levels both in the mPFC and, for the first time, in the dorsal caudate of antipsychotic-naïve patients with FEP, which normalized in both regions following 4 weeks of antipsychotic treatment.

中文翻译：

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前额叶和纹状体γ-氨基丁酸水平和抗精神病药物治疗对首发精神病患者的影响

背景 有报道称，在不使用抗精神病药的精神分裂症患者中，内侧前额叶皮层 (mPFC) 中 γ-氨基丁酸 (GABA) 的水平异常升高。这种 GABA 升高是否也存在于其他大脑区域并在抗精神病药治疗后持续存在之前尚未研究过。方法 28 名初次服用抗精神病药的首发精神病 (FEP) 患者和 18 名健康对照受试者完成了这项研究。在针对 mPFC 和第二个区域背尾尾状核进行基线质子磁共振波谱扫描后，FEP 患者接受口服利培酮治疗 4 周，初始剂量为 1 毫克/天，根据临床判断根据需要进行滴定。经过 4 周的治疗后，两组都被带回进行结果磁共振波谱扫描，这与在基线时进行的扫描相同。结果 在基线时，与健康对照受试者相比，FEP 患者的 mPFC 和背尾尾状核中都发现了更高的 GABA 水平。在抗精神病药治疗 4 周后，FEP 患者的 GABA 水平相对于 mPFC 的基线下降，但仅在背尾尾状核中相对于基线的趋势水平下降。对于任一脑区，FEP 患者和健康对照受试者在 4 周或治疗后的 GABA 水平没有差异。结论 本研究的结果记录了 mPFC 中 GABA 水平的升高，并且首次在未接受抗精神病药的 FEP 患者的背尾尾状核中升高，