目的：探索抑郁症患者血浆内源性阿片肽水平的差异及其与抑郁或焦虑严重程度的关系，分析内源性阿片肽是否有助于抑郁症诊断和治疗疗效的判断。方法：纳入2020年6月—2023年2月于我院就诊的抑郁症患者96例作为抑郁症组，以及招募50名健康者作为对照组，收集一般人口学资料及临床数据[汉密尔顿抑郁量表（Hamilton depression scale 17, HAMD-17）、14项汉密尔顿焦虑量表（Hamilton anxiety scale 14, HAMA-14）、30项抑郁症状自评问卷（inventory of depressive symptomatology 30, IDS-30）]；采集外周血，提取血浆，使用酶联免疫吸附测定（enzyme-linked immunosorbent assay， ELISA）比较2组血浆β-内啡肽（β-endorphin， β-EP）和脑啡肽（enkephalin， ENK）的水平差异。因疫情反复影响等原因，仅28例患者同意进行后续的随访研究和采血计划。随访期间治疗均依照门诊医师制定的方案，不作任何研究干预。8周后随访患者4例失访，共收集24例患者临床数据及血样，对随访患者的临床数据及血样结果作比较。结果：抑郁症组血浆β-EP水平显著高于对照组[49.48（36.79,61.14） ng/mL比30.84（23.51,38.14） ng/mL， P<0.05]，ENK水平显著低于对照组[15.85（10.51,19.56） ng/mL比23.72（21.44,26.98） ng/mL，P<0.05]；相关性分析显示基线时β-EP、ENK水平与3个量表评分均无明显相关性（均P>0.05）。痊愈组和未痊愈组治疗8周后，血浆β-EP、ENK与基线相比均无显著差异（P>0.05）。结论：β-EP、ENK有望成为抑郁症的生物标志物。

Objective To explore the difference of plasma endogenous opioid peptide level in patients with depression and its relationship with the severity of depression or anxiety, and analyze whether endogenous opioid peptide is helpful to the diagnosis and treatment of depression. Methods A total of 96 patients with depression who visited our hospital from June 2020 to February 2023 were enrolled as the depression group, and 50 healthy subjects were recruited as the control group. General demographic and clinical data [Hamilton depression scale 17(HAMD-17), Hamilton anxiety scale 14(HAMA-14), inventory of depressive symptomatology 30(IDS-30)] were collected. Peripheral blood was collected, plasma was extracted, and plasma β-endorphin (β-EP) and enkephalin (ENK) were compared between the two groups using enzyme-linked immunosorbent assay (ELISA). Due to the repeated impact of the epidemic, only 28 patients agreed to follow-up studies and blood collection plans. During the follow-up period, the treatment was in accordance with the plan made by outpatient physician, and there was not any research intervention. After 8 weeks of follow-up, 24 patients finished the studies, and their clinical data and blood samples were collected and compared. Results The plasma β-EP level in depression group was significantly higher than that in control group [49.48（36.79,61.14） ng/mL vs 30.84（23.51,38.14）ng/mL， P<0.05], while the plasma ENK level was significantly lower than that in control group [15.85（10.51,19.56）ng/mL vs 23.72（21.44,26.98）ng/mL， P<0.05]. Correlation analysis showed that there was no significant correlation between β-EP and ENK levels at baseline and the scores of the three scales (P > 0.05). There were no significant differences in plasma β-EP and ENK levels between cured group and non-cured group after 8-week of treatment compared to baseline (P > 0.05). Conclusions β-EP and ENK are expected to be biomarkers of depression.