The Relationship Between Abnormal Brain Function And Curative Effects Of First Episode And Recurrent Depression

Background: Major depressive disorder is a mental disorder clinically characterized by persistent and pervasive feelings of sadness,guilt,and worthlessness.It is usually highly recurrent,and an individual with depression will have 5 to 9 separate episodes with in their lifetime.Despite the progress in the development of antidepressants,still about one-third of depressed patients fail to respond.Resting-state functional magnetic resonance imaging(RSf MRI)has provided important results in the study of depression and which contribute to the identification of biomarkers for treatment response.Objective: The purpose of this study is to explore the different response to antidepressant between first-episode and recurrent depression and its cerebral mechanism.Method: Patients with depression(n=50)meeting Diagnostic and Statistical Manual of Mental Disorder,fifth edition(DSM-5)diagnostic criteria were recruited.All subjects were divided into first-episode(n= 19)and recurrent group(n= 31).The Hamilton Depression Rating Scale(HAMD-17)and RS-f MRI data of all patients were collected at baseline.After antidepressant treatment for two weeks,the subjects were revalued by HAMD-17.The difference of low-frequency fluctuation(ALFF)at baseline and the reducing rate of HAMD-17 between the two groups was determined,P-value <0.05 was considered statistically significant.Results: No significant differences were found in age,gender,education,family history and HAMD-17 score.Compare to first-episode group,the curative effect of recurrent group was better.The ALFF of first episode group was decreased in the left middle frontal gyrus(MFG),left inferior temporal gyrus(ITG),left fusiform gyrus,but higher in the cerebellum posterior lobe compared to recurrent group(all P < 0.05,corrected by Threshold-Free Cluster Enhancement(TFCE).Correlation analyses between the ALFF of the above brain areas and curative effect showed that the ALFF in the left ITG gyrus of the first episode group was significantly positively related with curative effect(P = 0.038,Figure 2).Conclusion: The number of episode may affect the short term antidepressant treatment outcome.ALFF in left ITG might be associated with the different short-term curative effect between first-episode and recurrent depression.