Orbitofrontal cortex gray matter volumes in bipolar disorder patients: a region-of-interest MRI study

Authors

  • Fabiano G Nery,

    1. Department of Psychiatry, The University of Texas Health Science Center at San Antonio (UTHSCSA)
    2. South Texas Veterans Health Care System, Audie L. Murphy, San Antonio, TX, USA
    3. Department of Psychiatry, University of São Paulo Medical School, São Paulo, Brazil
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  • Hua-Hsuan Chen,

    1. Department of Radiology, University of Cincinnati, Cincinnati, OH
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  • John P Hatch,

    1. Department of Psychiatry, The University of Texas Health Science Center at San Antonio (UTHSCSA)
    2. Department of Orthodontics, UTHSCSA, San Antonio, TX
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  • Mark A Nicoletti,

    1. Center of Excellence for Research and Treatment of Bipolar Disorders (CERT-BD), Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC, USA
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  • Paolo Brambilla,

    1. Department of Pathology and Experimental & Clinical Medicine, Section of Psychiatry, University of Udine
    2. Scientific Institute IRCCS ‘E. Medea’, Udine, Italy
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  • Roberto B Sassi,

    1. Department of Psychiatry, University of São Paulo Medical School, São Paulo, Brazil
    2. Department of Psychiatry, Harvard Medical School, Boston, MA
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  • Alan G Mallinger,

    1. Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, MD
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  • Matcheri S Keshavan,

    1. Department of Psychiatry and Behavioral Sciences, Wayne State School of Medicine, Detroit, MI, USA
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  • Jair C Soares

    1. Center of Excellence for Research and Treatment of Bipolar Disorders (CERT-BD), Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC, USA
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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.

Fabiano G. Nery, MD, Bipolar Disorder Research Group, Institute and Department of Psychiatry, University of São Paulo Medical School, Rua Dr. Ovídio Pires de Campos, 785, São Paulo/SP, Brazil 04503-010. Fax: +55 11 3069-7928; e-mail: fabiano_nery@hotmail.com

Abstract

Objectives:  Functional and postmortem studies suggest that the orbitofrontal cortex (OFC) is involved in the pathophysiology of bipolar disorder (BD). This anatomical magnetic resonance imaging (MRI) study examined whether BD patients have smaller OFC gray matter volumes compared to healthy comparison subjects (HC).

Methods:  Twenty-eight BD patients were compared to 28 age- and gender-matched HC. Subjects underwent a 1.5T MRI with 3D spoiled gradient recalled acquisition. Total OFC and medial and lateral subdivisions were manually traced by a blinded examiner. Images were segmented and gray matter volumes were calculated using an automated method.

Results:  Analysis of covariance, with intracranial volume as covariate, showed that BD patients and HC did not differ in gray matter volumes of total OFC or its subdivisions. However, total OFC gray matter volume was significantly smaller in depressed patients (n = 10) compared to euthymic patients (n = 18). Moreover, total OFC gray matter volumes were inversely correlated with depressive symptom intensity, as assessed by the Hamilton Depression Rating Scale. OFC gray matter volumes were not related to lithium treatment, age at disease onset, number of episodes, or family history of mood disorders.

Conclusions:  Our results suggest that abnormal OFC gray matter volumes are not a pervasive characteristic of BD, but may be associated with specific clinical features of the disorder.

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