Zheng Huirong, Yang Wanqun, Zhang Bin, Hua Guanmin, Wang Shibin, Jia Fujun, Guo Guangquan, Wang Wenjing, Quan Dongming
Guangdong Mental Health Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Affliated School of Medicine of South China University of Technology, Guangzhou, China.
Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
J Affect Disord. 2020 Mar 15;265:193-199. doi: 10.1016/j.jad.2020.01.059. Epub 2020 Jan 15.
Obsessive Compulsive Disorder (OCD) is characterized by hyperactivity in a network of forebrain structures, including the anterior cingulate cortex (ACC). Convergent evidence suggests that glutamatergic dysfunction may contribute to the disorder. Skin picking disorder (SPD) was listed as one of the obsessive-compulsive and related disorders, which is often comorbid with OCD and share overlapping phenomenology and pathophysiology. However, potential confounding effects between the two diagnostic effects on neurotransmitter levels remain largely unexamined.
We examined the pregenual anterior cingulate cortex (pACC) glutamate and other neurochemicals in 62 subjects using a single-voxel acquisition 1H MRS at 3Tesla; of these, 47 subjects yielded usable measurements of both glutamate and glutamine and were included in the analysis (17 medicated with OCD alone, 13 medicated with comorbid OCD + SPD, 17 healthy control).
OCD with comorbid SPD showed significantly lower pACC glutamate than in patients without SPD (p = 0.001) or control subjects (p = 0.035). OCD without SPD subjects showed pACC glutamate levels indistinguishable from controls (p = 0.501). In the OCD with SPD subjects, glutamate was correlated with Y-BOCS total score in female patients (n = 9, r = 0.69, p = 0.041).
The main limitation of the study was the cross-sectional data. Our patients were on SSRI medication which may have modified the effect of SPD and OCD interaction on glutamate activity.
Our results suggest that alterations of the glutamatergic system may play an important role in the pathophysiology of a subgroup of OCD and reduced pACC glutamate may be a biomarker of a distinct subset of OCD patients.
强迫症（OCD）的特征是包括前扣带回皮质（ACC）在内的前脑结构网络活动亢进。越来越多的证据表明，谷氨酸能功能障碍可能与该疾病有关。皮肤搔抓障碍（SPD）被列为强迫症及相关障碍之一，它常与强迫症共病，且具有重叠的现象学和病理生理学特征。然而，这两种诊断对神经递质水平的潜在混杂影响在很大程度上仍未得到研究。
我们使用3特斯拉的单体素采集1H MRS对62名受试者的膝前扣带回皮质（pACC）中的谷氨酸和其他神经化学物质进行了检测；其中，47名受试者获得了谷氨酸和谷氨酰胺的可用测量值，并被纳入分析（17名单纯患有强迫症且正在服药的患者，13名患有强迫症合并SPD且正在服药的患者，17名健康对照者）。
合并SPD的强迫症患者的pACC谷氨酸水平显著低于无SPD的患者（p = 0.001）或对照受试者（p = 0.035）。无SPD的强迫症患者的pACC谷氨酸水平与对照组无显著差异（p = 0.501）。在合并SPD的强迫症患者中，女性患者（n = 9，r = 0.69，p = 0.041）的谷氨酸水平与耶鲁布朗强迫症量表（Y - BOCS）总分相关。
该研究的主要局限性在于其横断面数据。我们的患者正在服用选择性5-羟色胺再摄取抑制剂（SSRI）药物，这可能改变了SPD与强迫症相互作用对谷氨酸活性的影响。
我们的结果表明，谷氨酸能系统的改变可能在一部分强迫症的病理生理学中起重要作用，pACC谷氨酸水平降低可能是一部分强迫症患者的生物标志物。
