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Neuroanatomical abnormalities as risk factors for bipolar disorder

Authors

  • Tomas Hajek,

    1. Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
    2. Prague Psychiatric Center and Charles University, 3rd School of Medicine, Prague, Czech Republic
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  • Normand Carrey,

    1. Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
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  • Martin Alda

    1. Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
    2. Prague Psychiatric Center and Charles University, 3rd School of Medicine, Prague, Czech Republic
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  • The authors of this paper do not have any commercial associations that might pose a conflict of interest in connection with this manuscript.

Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, 5909 Veteran's Memorial Lane, Halifax, Nova Scotia, B3H 2E2, Canada. Fax: 1 902 473 1583; e-mail: tomas.hajek@dal.ca

Abstract

Objective:  Neuroimaging studies show structural brain abnormalities in bipolar patients. Some of the abnormalities may represent biological risk factors conveying vulnerability for the disease. This paper aims to identify neuroanatomical risk factors for bipolar disorder (BD).

Methods:  We reviewed magnetic resonance imaging (MRI) findings in populations in which the effects of the disease or treatment are minimal or where the chances of finding genetically coded risk factors shared within the families are increased. Such populations include unaffected relatives of bipolar patients, first-episode patients, children or adolescents with BD and patients with familial BD.

Results:  MEDLINE search revealed 30 relevant scientific papers. Abnormalities in the volume of the striatum, left hemispheric white matter, thalamus and anterior cingulate as well as quantitative MRI signal hyperintensities were identified already in unaffected relatives of bipolar patients. Subjects in the early stages of the disease showed volume changes of the ventricles, white matter, caudate, putamen, amygdala, hippocampus and the subgenual prefrontal cortex. Reduction in the subgenual prefrontal cortex volume was replicated in three of four studies in patients with familial BD.

Conclusions:  Possible candidates for neuroanatomical risk factors for BD are volumetric abnormalities of the subgenual prefrontal cortex, striatum, white matter, and probably also the hippocampus and amygdala. Qualitative finding of white matter hyperintensities was already utilized as an endophenotype.

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