There are relatively few studies evaluating brain structure in bipolar disorder (BD), the results of which have been largely inconsistent, both in terms of what abnormalities are present in BD and whether they show any similar abnormalities to those found in schizophrenia. One possibility that might explain the varying degree of reported similarity in structural findings in schizophrenia and BD is that there might be effects of BPD diagnostic subtype associated with brain structure. One viewpoint that contrasts schizophrenia and BD considers psychotic (PBD) to differ from non-psychotic (NPBD) subtypes in terms of shared pathophysiology with schizophrenia. PBD has been reported as being of special interest, as it shares symptomatic overlap with schizophrenia, "runs in families", shares a chromosomal linkage to the 13q13-32 and 22q12 with schizophrenia, shows similar increases in dopamine receptor Bmax induced by \[c-11\] N-methylspiperone positron emission tomography and similar working memory impairments as in schizophrenia. If PBP and NPBP are associated with different forms of brain pathology, then merging the two entities into a single "bipolar group" might obscure relevant anatomic differences if these occur primarily in only one group. In this proposal, the investigators will focus on subcortical gray and white matter structures commonly found to be abnormal in schizophrenia. Thus, the investigators will evaluate the volume and shape of the hippocampus, thalamus and basal ganglia, as well as measures of structural integrity of the corpus callosum and its various subregions.
