White matter hyperintensities and major affective disorders

In the last decade, neuroimaging techniques provide an important evidenced-based approach to investigate mental disorders. Researchers have suggested that brain white matter hyperintensities (WMHs) may be involved in the pathophysiology of major affective disorders. WMHs represent ependymal loss and altered myelination of white matter and appear as high intensity signal lesions on T2-weighted magnetic resonance images (MRI). Structural MRI abnormalities such as deep and periventricular WMHs depending on localization have been commonly found in older and younger patients with affective disorders. WMHs are generally related to vascular diseases, however the underlying processes determining these lesions are only partially known. It has been hypothesized that WMHs might cause abnormalities in neural circuits critically involved in emotional processes and mood regulation, resulting in increased vulnerability to psychiatric morbidity. Overall, white matter abnormalities may represent presumable biological substrates of vulnerability leading to the emergence of both affective disorders and suicidal behaviour. However, there are mixed results in the current literature regarding whether unipolar or bipolar patients who have attempted suicide present more deep or periventricular WMHs compared to those who did not. Aiming to critically review the current literature about the association among WMHs, major affective disorders and suicide behaviour, we performed a detailed search of Medline, PsycInfo, and Web of Science databases. All publications available up to May 2012 were considered. © Nova Science Publishers, Inc.