Xu W, et al. - The association between abnormal iron metabolism and non-motor symptoms (NMS) of Parkinson’s disease (PD) was studied. For this research, 70 PD patients and 64 healthy controls were consecutively selected to compare serum iron, ceruloplasmin, ferritin, and transferrin levels. They assessed five classic NMS, including depression, anxiety, pain, sleep disorder, and autonomic dysfunction in PD patients utilizing the Hamilton Depression Scale (HAMD), the Hamilton Anxiety Scale (HAMA), the short form of the McGill Pain Questionnaire, the Pittsburgh Sleep Quality Index and the Scale for Outcomes in Parkinson’s disease for Autonomic Symptoms, respectively. They suggested that abnormal iron metabolism could play a crucial role in the pathogenesis of depression and anxiety in PD as well as serums levels of iron and transferrin could be peripheral markers for depression and anxiety in PD.