目的 ·探索精神病临床高危（clinical high risk，CHR）人群和首发精神分裂症（first episode schizophrenia，FES）患者听觉事件相关电位 P300的 θ振荡改变，以及与临床症状之间的关系。方法 ·招募 18名精神病 CHR患者（CHR组）、 18名 FES患者（FES组）以及 19名健康对照（健康对照组），完成标准听觉 Oddball实验范式，并用 64导联脑电帽记录脑电活动。选择 Fz、Cz、Pz电极进行 P300波幅、峰潜伏期以及 P300的 θ振荡时－频分析。结果 · 3组被试的 P300波幅间差异有统计学意义（P0.004），其中 FES组（P0.001）及 CHR组（P0.026）的波幅均显著小于健康对照组， CHR组和 FES组间差异无统计学意义（P>0.05）。θ引发能量值在 3组间有显著差异（P0.022），其中 FES组显著低于健康对照组（P0.008），CHR组边缘性低于健康对照组（P0.054），CHR组与 FES组间差异无统计学意义（P>0.05）。θ诱发能量值在 3组间仅有边缘性差异（P0.054）。相关性分析发现， FES组的阳性与阴性症状量表总分及部分分量表评分与 Cz电极、 Pz电极的 P300波幅具有显著相关性（均 P<0.05）。结论 · CHR与 FES患者的听觉 P300波幅以及 P300的 θ振荡均存在异常，但 CHR患者的改变较 FES患者轻微，且其 P300的 θ振荡仅局限于引发能量受损，而诱发能量并未受损。

Objective · To explore the relationship between θ oscillation of auditory event-related potential P300 and clinical symptoms in the patients with clinical high risk (CHR) of psychosis or first episode schizophrenia (FES). Methods · A total of 18 patients with CHR of psychosis (CHR group), 18 patients with FES (FES group) and 19 healthy controls (control group) were recruited to complete the standard auditory Oddball paradigm as well as electroencephalogram (EEG) recording with 64-channel EEG cap. Fz, Cz and Pz electrodes were selected to compare the amplitudes and peak latent periods among the three groups, and time-frequency analysis of the θ oscillation in P300 was performed. Results · There was significant difference in the amplitudes of P300 among the three groups (P0.004). The amplitudes of P300 in FES group (P0.001) and CHR group (P0.026) were both significantly lower than that of control group. There was no difference between CHR group and FES group in P300 amplitude (P>0.05). θ Oscillation induced power was significantly different among the three groups (P0.022). The induced power value of FES group was significantly lower than that of control group (P0.008); and it was marginally lower in CHR group as compared to that of control group (P0.054). There was no difference between CHR group and FES group (P>0.05). There was trending difference in θ oscillation evoked power among the three groups (P0.054). The correlation analysis showed that the total and subscale scores of Positive and Negative Syndrome Scale in FES group were significantly correlated with the amplitudes of P300 at Cz and Pz electrodes (P<0.05). Conclusion · There are significant abnormalities in the amplitude of auditory P300 and θ oscillation of P300 in both CHR and FES patients; however, the change in CHR patients is less severe than that of FES patients. The impaired θ oscillation of P300 in CHR patients is limited to induced power, but evoked power is not impaired.