Similarities and differences of regional brain activity between first-episode drug-naïve anxious and nonanxious MDD patients

Anxiety is one of the most common symptoms in major depressive disorder (MDD), and anxious MDD patients exhibit more complicated and serious symptoms compared with nonanxious MDD patients. However, the differences of pathological mechanisms underlying anxious and nonanxious MDD are unclear. The present study aimed to explore the differences of central neural correlates between anxious and nonanxious MDD patients. Resting-state functional magnetic resonance imaging data were collected form 42 first-episode drug-naïve anxious MDD, 42 nonanxious MDD patients and 45 healthy controls (HCs). Regional homogeneity (ReHo) values were calculated and compared between groups using the gray matter volume as covariates. Relationships between ReHo values and emotional scale scores were evaluated. Receiver operating characteristic (ROC) curve was used to determine the suitability of altered brain region for distinguishing anxious MDD from nonanxious MDD. In comparison with HCs, anxious MDD patients showed decreased ReHo values in the inferior temporal gyrus, precuneus, supplementary motor area and putamen. Apart from the above abnormal brain regions, nonanxious MDD patients additionally demonstrated decreased ReHo values in the middle frontal gyrus when compared with HCs. Decreased ReHo values were identified in the right parahippocampal gyrus of anxious MDD patients when compared with nonanxious MDD patients. Moreover, negative relationship was identified between ReHo values of the right supplementary motor area and 17-item Hamilton Depression Rating Scale scores. Finally, ROC analysis revealed that the right parahippocampal gyrus might be helpful for distinguishing anxious MDD from nonanxious MDD. These findings suggested that the central pathological mechanisms of both anxious and nonanxious MDD might be associated with decreased spontaneous brain activities. Moreover, broader brain regions would exhibit decreased activation when accompanied by comorbid anxiety and the right parahippocampal gyrus might be a potential neuroimaging marker for distinguishing anxious MDD patients from those without anxiety.