White-Matter Abnormalities in Bipolar Patients and Their Siblings

Patients with bipolar disorders exhibit abnormalities of white-matter integrity in several brain regions, but whether these abnormalities result from disease processes or treatment effects is unresolved. Investigators used diffusion tensor imaging to assess white-matter integrity in 64 patients with uncomplicated, clinically stable bipolar I disorder (mean age, 32; mean illness duration, 10 years), 60 of their unaffected siblings (mean age, 30; resulting in 54 proband–sibling pairs), and 46 healthy controls of similar age, education, and IQ.

Patients were receiving a variety of mood stabilizers, antidepressants, and other medications. Studied siblings had no histories of bipolar spectrum disorder. Patients and their siblings showed less whit…