We propose to investigate the connectivity of white matter tracts using diffusion tensor imaging (DTI) in children with very early onset bipolar disorder (BPD). We hypothesize that the connectivity between the prefrontal cortex and the temporal lobe and parietal lobe and limbic structures will be abnormal, indicating white matter and gray matter deficits in early onset BPD. We also hypothesize that the superior lateral fasciculus cingulum bundle and the inferior lateral fasciculus will have decreased fractional anisotropy in very early onset BPD relative to healthy controls.