Subcortical hyperintensities on brain magnetic resonance imaging: a comparison of normal and bipolar subjects

Bipolar disorder has been reported to occur frequently in a number of subcortical diseases. This suggests that subcortical structures may be involved in the etiology of bipolar disorder in some patients. With the advent of brain magnetic resonance imaging (MRI), in vivo visualization of the subcortical white and gray matter is now possible, allowing the examination of these structures. The authors report a higher occurrence of deep white matter lesions in bipolar patients (44%) compared with age-matched controls (6%). The neuroanatomic and clinical correlates of these lesions will be discussed, along with their potential pathophysiologic significance.