The Evaluation of Amygdala Volumes in Adolescents with Bipolar Disorder Type I

Objectives:The aim of the present study is to investigate whether the variables of the disorder affect amygdala volumes in the adolescents with Bipolar Disorder (BD) type I and to compare the possible amygdala volume changes with healthy adolescents.Materials and Methods:Seventeen adolescents aged between 13 and 19 years, who had BD type I according to Diagnostic and Statistical Manual of Mental Disorders-IV criteria that was either already been followed up or got the diagnosis after their admission to Dokuz Eylül University Faculty of Medicine, Department of Child and Adolescent Psychiatry between May 2008 and October 2008, were included in the study. Twelve adolescents between 13 and 19 years old and without any psychiatric diagnosis were included in the healthy control group. The magnetic resonance imaging (MRI) scans of all participants were performed by using an MRI machine with 1.5 Tesla power (Gyroscan Intero, Philips, Netherlands) and standard head coils. The MRI scans of the cases were made during euthymic phase. The phase of euthymia was defined according to Young Mania Rating Scale and Hamilton Depression Rating Scale.Results:The evaluation and comparison of both right and left amygdala volumes between the patient and the control group revealed no significant difference. However, in the patient group, negative correlation was found between right and left amygdala volumes and the duration of the disorder (for the right amygdala p=0.026; for the left amygdala p=0.031).Conclusion:The differences detected in amygdala volumes by structural MRI scans in adolescent and adult BD samples may reflect underlying pathophysiologic differences between the early onset and the late onset of the disorder.