Abnormal corpus callosum myelination in pediatric bipolar patients

BACKGROUND: Decreased signal intensity in the corpus callosum, reported in adult bipolar disorder patients, has been regarded as an indicator of abnormalities in myelination. Here we compared the callosal signal intensity of children and adolescents with bipolar disorder to that of matched healthy subjects, to investigate the hypothesis that callosal myelination is abnormal in pediatric bipolar patients. METHODS: Children and adolescents with DSM-IV bipolar disorder (n=16, mean age+/-S.D.=15.5+/-3.4 y) and matched healthy comparison subjects (n=21, mean age+/-S.D.=16.9+/-3.8 y) underwent a 1.5 T MRI brain scan. Corpus callosum signal intensity was measured using an Apple Power Mac G4 running NIH Image1.62 software. RESULTS: Bipolar children and adolescents had significantly lower corpus callosum signal intensity for all callosal sub-regions (genu, anterior body, posterior body, isthmus and splenium) compared to healthy subjects (ANCOVA, all p<0.05, age and gender as covariates). LIMITATIONS: Relatively small sample size. CONCLUSIONS: Abnormalities in corpus callosum, probably due to altered myelination during neurodevelopment, may play a role in the pathophysiology of bipolar disorder among children and adolescents.