Structural brain and neuropsychometric changes associated with pediatric bipolar disorder with psychosis.

OBJECTIVES: To identify neuropsychological and structural brain changes using a combination of high-resolution structural and diffusion tensor imaging in pediatric bipolar disorder (PBD) with psychosis (presence of delusions and or hallucinations).
METHODS: We recruited 15 patients and 20 euthymic age- and gender-matched healthy controls. All subjects underwent high-resolution structural and diffusion tensor imaging. Voxel-based morphometry (VBM), tract-based spatial statistics (TBSS), and probabilistic tractography were used to analyse magnetic resonance imaging data.
RESULTS: The PBD subjects had normal overall intelligence with specific impairments in working memory, executive function, language function, and verbal memory. Reduced gray matter (GM) density was found in the left orbitofrontal cortex, left pars triangularis, right premotor cortex, occipital cortex, right occipital fusiform gyrus, and right crus of the cerebellum. TBSS analysis showed reduced fractional anisotropy (FA) in the anterior corpus callosum. Probabilistic tractography from this cluster showed that this region of the corpus callosum is connected with the prefrontal cortices, including those regions whose density is decreased in PBD. In addition, FA change was correlated with verbal memory and working memory, while more widespread reductions in GM density correlated with working memory, executive function, language function, and verbal memory.
CONCLUSIONS: The findings suggest widespread cortical changes as well as specific involvement of interhemispheric prefrontal tracts in PBD, which may reflect delayed myelination in these tracts.