MRI studies in children at risk of BD, our understanding of the neurobiology of BD and abnormalities in the studied regions, regions that predispose to the development of our understanding of PBB will shed light on the etiology of the disorder. In this study, the cranial MRI findings and clinical features in adolescents with bipolar disorder and the same age and sex matched children who have parents with BD and healthy controls were investigated. Since there is few studies that evaluate these three groups, there is a need to increase our knowledge on this issue.