A preliminary study of the functioning network in first-episode medication-naive adolescent depression

Objective: To compare the brain function between the first-episode medication-naive depressive adolescents and healthy controls by using the theory of complex network so as to further elucidate the neural pathological mechanism of adolescent depressive patients.

Results: The brain neural network topology presented a relatively chaotic state in the first-episode medication-naive depressive adolescents compared with that in the healthy controls. The characteristics of small world network of brain decreased in the first-episode medication-naive depressive adolescents. The overall efficiency of neural network decreased, too. The value of the amygdala in topological structure was increased. Functional connections between brain areas such as the amygdala and the temporal cortex, the amygdala and the parietal cortex, the amygdala and the postcentral gyrus, prefrontal and inferior parietal lobules were increased. The increases of functional connections were positively correlated with the course of disease. In the resting state background, the values were increased in such areas as anterior cingulate cortex, dorsolateral prefrontal, prefrontal cortex medial segment, prefrontal segment, insular lobe, and temporal lobe cortex.

Methods: We recruited 16 patients with depression in this study. All the patients were in accordance with American Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV). All the patients had never received any treatment. Another 16 healthy controls served as controls. The two groups were similar in age and education. All subjects were right-handed. The thresholds of complex brain network construction were made with different correlation coefficients.

Conclusion: The amygdale plays an important role in the occurrence and development of depression. Abnormality of neural network topology in the amygdala is the biological marker of depression susceptibility in adolescent depressive patients. There are multiple abnormal structures and functions in the brain in depressive patients.