目的 ·探索并分析精神病临床高危人群的烟酸皮肤反应敏感度特点。方法 ·入选 2016年 6月—2018年 6月于上海交通大学医学院附属精神卫生中心门诊就诊的符合前驱期综合征标准的精神病临床高危患者 105例（高危组）、符合《精神疾病诊断与统计手册（第四版）》中精神分裂症诊断标准的首发精神分裂症患者 51例（首发组），以及年龄、性别与高危组患者相匹配的健康志愿者 54名（健康对照组）为研究对象，检测其烟酸皮肤反应。采用单因素重复测量方差分析（single factor repeated measurement variance analysis， MANOVA）比较 3组对象的烟酸皮肤反应分数。采用 χ2检验比较 3组对象的烟酸反应阴性率。结果 ·与健康对照组相比，高危组与首发组患者的烟酸皮肤红晕反应在各浓度及时间点下均有所减弱。 MANOVA显示，烟酸皮肤反应具有显著的组别效应（F1.746， P0.009），即组别与烟酸浓度（F1.628，P0.138）、与烟酸反应时间（F0.851，P0.531）均无显著性交互作用。高危组患者的烟酸反应总分显著低于健康对照组（t-2.697，P0.008）。当烟酸浓度为 0.1 mol/L、反应时间为 5 min（χ216.709，P0.000）时以及烟酸浓度为 0.001 mol/L、反应时间为 20 min（χ26.380，P0.041）时， 3组对象的烟酸反应阴性者占比间差异具有统计学意义。结论 ·烟酸皮肤反应减弱这一表征不仅可发生在精神分裂症患者中，还可发生在处于前驱期的精神病临床高危人群中。烟酸皮肤反应可能是精神分裂症的一种早期生物学标记。

Objective · To explore and analyze the characteristics of nicotinic acid skin sensitivity in clinical high risk (CHR) population of psychosis. Methods · One hundred and five patients with CHR of psychosis (CHR group) and fifty-one patients with first episode schizophrenia (FES) (FES group) in Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine Jun. 2016 to Jun. 2018, and fifty-four healthy controls (HC group) were included. The patients of CHR group met the criteria of prodromal syndromes, and the patients of FES group met the diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition). The patients of HC group were matched with CHR group in age and gender . The niacin skin flush of the three groups were detected. The niacin skin flush scores of the three groups were comparedsingle factor repeated measurement variance analysis (MANOVA). The niacin flush negative rates of the three groups were comparedChi-square test. Results · Compared with HC group, the niacin skin flush of CHR group and FES group reduced at different concentrations and time points. MANOVA showed a significant main group effect of niacin skin flush (F1.746, P0.009). There were no significant group × concentration interaction (F1.628, P0.138) and group × time interaction (F0.851, P0.531). Compared with HC group, the niacin total flush scores of CHR group were lower (t-2.697, P0.008). The significant differences of the proportion of patients with negative niacin reaction among the three groups were found for the concentration of 0.1 mol/L at 5 min (χ216.709, P0.000) and 0.001 mol/L at 20 min (χ26.380, P0.041). Conclusion · The reduction of the niacin skin flush can occur not only in the patients with schizophrenia but also in the CHR of psychosis in the precursor phase. Niacin skin flush may be an early biological marker of schizophrenia.