Structural trait markers of bipolar disorder: disruption of white matter integrity and localized gray matter abnormalities in anterior fronto-limbic regions.

摘要

Kraepelinian's classification of major psychoses suggests that bipolar disorder (BD) is an illness distinct from schizophrenia. Traditionally, neuroanatomical abnormalities were considered as trait markers of schizophrenia rather than BD. Schizophrenia is associated with enlargement of ventricles; gray matter abnormalities in a number of regions including the insula, superior temporal gyrus, anterior cingulate cortex (ACC), hippocampus, and thalamus (1,2); and disrupted white matter integrity in frontosub-cortical, frontotemporal, and interhemispheric tracts (3) (Bora et al. submitted). However, familial and genetic studies have identified shared risk factors relevant to both schizophrenia (4) and BD and that there are similarities in cognitive deficits observed in both disorders (5). These findings suggest that neuroanatomical abnormalities might also be trait markers of BD. However, unlike BD, schizophrenia also shares genetic susceptibility factors with neuro-developmental disorders (4,6), suggesting that some of the neuroanatomical abnormalities might be specific to schizophrenia.