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Background: The amygdala is repeatedly implicated as a critical component of the neurocircuitry regulating emotional valence. Studies have frequently reported reduced amygdala volumes in children and adolescents with bipolar disorder (BD). Brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) play critical roles in growth, differentiation, maintenance, and synaptic plasticity of neuronal systems in adolescent brain development. The aim of the present study was to assess amygdala volumesand its correlation with serum levels of NGF and BDNF in euthymic adolescents with BD and healthy controls., Methods: Using structural MRI, we compared the amygdala volumes of 30 euthymic subjects with BD with 23 healthy control subjects aged between 13 and 19 years during a naturalistic clinical follow-up. The boundaries of the amygdala were outlined manually. Serum BDNF and NGF levels were measured using sandwich-ELISA and compared between the study groups., Results: The right or left amygdala volume did not differ between the study groups.The right and left amygdala volumes were highly correlated with levels of BDNF in the combined BD group and the valproate-treated group.Both R and L amygdala volumes were correlated with BDNF levels in healthy controls. The left amygdala volumes were correlated with BDNF levels in the lithium-treated group., Limitations: This cross-sectional study cannot inform longitudinal changes in brain structure. Further studies with larger sample sizes are needed to improve reliability., Conclusions: The correlations between amygdala volumes and BDNF levels might be an early neuromarker for diagnosis and/or treatment response in adolescents with BD., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Structural neuroimaging studies in bipolar disorder (BD) have consistently identified several anatomical abnormalities in many brain areas related to mood regulation. Hippocampus is one of the key components of emotional regulatory networks in the brain. Evidence about hippocampal changes in BD is quite limited and inconsistent particularly for adolescent onset BD. It is aimed to compare hippocampus volumes of euthymic BD-I adolescents with healthy controls using structural MRI., Methods: Hippocampal volumes of seventeen youths between 13 and 19 age period with DSM-IV BD (seven boys) and twelve healthy comparison subjects (five boys) were compared using structural MRI. Differences in hippocampal volumes between groups were tested., Results: There was no significant difference between the right and left hippocampus volumes of patients with BD and the control group. However boys tended to have significantly larger right hippocampal volumes than girls both in BD and control group. Right hippocampal volumes were enlarged in lithium treated bipolar patients. This enlargement is not related to sex., Limitations: Future, longitudinal follow-up studies need large enough sample sizes of both sexes and a sex-matched healthy comparison group to sort out developmental, gender and medication influences on brain structures over time in BD., Conclusions: Lithium treatment in adolescent-onset BD has a significant effect on hippocampus volumes., (Copyright © 2012 Elsevier B.V. All rights reserved.)