Autoimmune-mediated obsessive–compulsive disorder (OCD) can occur in multiple sclerosis (MS). Here, a well-studied case study of a patient with OCD and MS-compatible diagnostic findings is presented. The 42-year-old female patient had displayed OCD symptoms for 6 years. Magnetic resonance imaging (MRI) identified several periventricular and one brainstem lesion suggestive of demyelination. Cerebrospinal fluid (CSF) analyses detected an increased white blood cell count, intrathecal immunoglobulin (Ig) G and IgM synthesis, CSF-specific oligoclonal bands, and a positive MRZ reaction. Neopterin was increased, but sarcoidosis was excluded. In the absence of neurological attacks and clues for MRI-based dissemination in time, a radiologically isolated syndrome, the pre-disease stage of MS, was diagnosed. Neurotransmitter measurements of CSF detected reduced serotonin levels. In the absence of visible strategic demyelinating lesions within the cortico-striato-thalamo-cortical circuits, OCD symptoms may relate to reduced intrathecal serotonin levels and mild neuroinflammatory processes. Serotonin abnormalities in MS should be studied further, as they could potentially explain the association between neuroinflammation and mental illnesses.

自身免疫介导的强迫症 (OCD) 可能发生在多发性硬化症 (MS) 中。本文介绍了对一名强迫症患者和 MS 兼容诊断结果进行充分研究的案例研究。该患者今年42岁，女性，已有6年强迫症症状。磁共振成像（MRI）发现了几个脑室周围和一个脑干病变提示脱髓鞘。脑脊液 (CSF) 分析检测到白细胞计数增加、鞘内免疫球蛋白 (Ig) G 和 IgM 合成、CSF 特异性寡克隆带以及阳性 MRZ 反应。新蝶呤增加，但排除结节病。在缺乏神经系统发作和基于 MRI 的及时传播线索的情况下，诊断出一种放射学孤立综合征，即 MS 的疾病前期阶段。脑脊液神经递质测量发现血清素水平降低。在皮质-纹状体-丘脑-皮质回路内没有明显的战略性脱髓鞘病变的情况下，强迫症症状可能与鞘内血清素水平降低和轻度神经炎症过程有关。应该进一步研究多发性硬化症中的血清素异常，因为它们可能解释神经炎症和精神疾病之间的关联。