目的：研究抑郁症患者事件相关电位P300的特点及其与患者健康问卷抑郁量表（PHQ-9）评分的相关 性，并分析其临床意义。方法：抑郁障碍患者36例纳入抑郁症组，34例健康者纳入正常对照组。2组均进行 PHQ-9的评分以及在单一视觉怪球任务下进行事件相关电位P300的采集，分析2组P300的潜伏期和幅值 的差异以及其与 PHQ-9 评分的相关性。结果：抑郁症组 C4、P4、T4、T6 导联的 P300 幅值低于对照组（P= 0.020、0.015、0.033、0.013）；PHQ-9评分与P300的幅值在C4、P4、F8、T4、T6电极存在负相关关系（r= －0.267、 －0.252、－0.285、－0.287、－0.335，P=0.026、0.036、0.017、0.016、0.005）。结论：事件相关电位P300改变作为 一项潜在客观指标可能可反映抑郁症患者的认知损害，依据患者PHQ-9的抑郁严重程度评估，对反应抑郁 症患者认知损害可能具有一定指导意义。

To explore the characteristics of event-related potential P300 in patients with depression and its correlation with the Patient Health Questionnaire (PHQ-9) scores. Methods: Thirty-six patients with depressive disorder were included into the depression group, and 34 healthy subjects were recruited as the control group. PHQ-9 scores were obtained from the subjects, and event-related potential P300 was collected under the visual oddball task in both groups. The difference of latency and amplitude of P300 between the two groups and its correlation with PHQ-9 scores was analyzed. Results: The P300 amplitude of the depression group compared with that of the normal control group was significantly reduced in the C4, P4, T4, and T6 electrodes (P=0.020, 0.015, 0.033, 0.013). PHQ-9 was negatively correlated with the amplitude of P300 at the C4, P4, F8, T4, and T6 electrodes (r=－0.267, －0.252, －0.285, －0.287, －0.335, P=0.026, 0.036, 0.017, 0.016, 0.005). Conclusion: The change of event-related potential P300 is a possible objective indicator to reflect the cognitive impairment of patients with depression. Based on the severity assessment by PHQ-9, it may have some guiding significance in indicating cognitive impairment in patients with depression.