Increased rates of white-matter hyperintensities have been a frequent finding in magnetic resonance imaging (MRI) studies

frequent finding in magnetic resonance imaging (MRI) studies evaluating individuals with bipolar disorder compared with healthy controls. Such findings have been reported in individuals with the early stages of bipolar disorder as well as in their unaffected relatives, and this has been taken as suggestive that white-matter hyperintensities could reflect abnormal neurodevelopmental processes in bipolar disorder (see Hajek et al for review). White-matter hyperintensities have also been associated with unipolar depression, particularly in late-onset cases. However, other MRI studies of mood disorders have reported negative results. Moreover, there have been conflicting findings regarding the frequency of white-matter hyperintensities in schizophrenia. Most studies of white-matter hyperintensities have been conducted with small and heterogeneous samples and this might account for the above inconsistencies. We have evaluated the presence of white-matter hyperintensities in a large sample of people with first-episode psychosis, including individuals with non-affective and affective psychoses, and compared them with people who were psychosis-free and from the same geographical areas. We sought to determine whether white-matter hyperintensities can be linked to affective or psychotic symptoms in general, or whether they would be specifically associated with bipolar disorder.