MRC Unit on Anxiety and Stress Disorders, Department of Psychiatry, University of Stellenbosch, South Africa.
J Psychiatry Neurosci. 2012 May;37(3):193-9. doi: 10.1503/jpn.110059.
There is evidence to suggest that obsessive-compulsive disorder (OCD) is associated with structural abnormalities in cortico-striato-thalamic circuits, yet the extent of white matter abnormalities is not well established. In this study, we used diffusion tensor imaging (DTI) to examine white matter integrity in specific regions of interest (ROIs) in patients with OCD.
Patients with OCD and sex-, age- and IQ-matched healthy controls underwent DTI. The primary objective was to explore whether patients with OCD had white matter abnormalities in the anterior limb of the internal capsule (ALIC), the uncinate fasciculus, the genu of the corpus callosum and the cingulum. The secondary objective was to evaluate the relation between fractional anisotropy and mean diffusivity in these ROIs and other clinical variables (including age at onset of OCD, OCD severity and levels of depressive and anxiety symptomatology) in patients with OCD.
There were 15 patients and 17 controls enrolled in our study. Compared with healthy controls, patients with OCD showed increased fractional anisotropy in bilateral regions of the ALIC adjacent to the body of the caudate, as well as decreased fractional anisotropy in the right anterior limb near the head of the caudate. Patients also had decreased mean diffusivity in the body of the right cingulum and the left anterior cingulum compared with controls. Correlational analyses revealed significant associations of fractional anisotropy and mean diffusivity in select circuits with OCD, depression and anxiety severity scores.
Inclusion of patients with OCD receiving pharmacotherapy may have been a limitation. In addition, the patients were heterogeneous in terms of their obsessive-compulsive symptom profiles; we did not distinguish between different obsessive-compulsive symptom dimensions.
The study results provide further evidence for OCD-related white matter abnormalities in the ALIC and cingulum, consistent with a cortico striatal model of OCD.
有证据表明，强迫症（OCD）与皮质-纹状体-丘脑回路的结构异常有关，但白质异常的程度尚不清楚。在这项研究中，我们使用弥散张量成像（DTI）检查 OCD 患者特定感兴趣区域（ROI）的白质完整性。
OCD 患者和性别、年龄和智商匹配的健康对照组接受了 DTI。主要目的是探讨 OCD 患者在前内囊肢（ALIC）、钩束、胼胝体膝部和扣带回白质是否存在白质异常。次要目的是评估这些 ROI 中的各向异性分数和平均弥散度与 OCD 患者其他临床变量（包括 OCD 发病年龄、OCD 严重程度和抑郁、焦虑症状水平）之间的关系。
我们纳入了 15 名患者和 17 名对照组。与健康对照组相比，OCD 患者双侧靠近尾状核体部的 ALIC 区域的各向异性分数增加，而靠近尾状核头部的右侧前肢的各向异性分数降低。与对照组相比，患者右侧扣带回体部和左侧前扣带回的平均弥散度也降低。相关分析显示，选择回路的各向异性分数和平均弥散度与 OCD、抑郁和焦虑严重程度评分显著相关。
纳入接受药物治疗的 OCD 患者可能是一个限制。此外，患者在强迫症状特征方面存在异质性；我们没有区分不同的强迫症状维度。
研究结果进一步提供了 OCD 相关的 ALIC 和扣带回白质异常的证据，与 OCD 的皮质纹状体模型一致。
