title: Distinct and Shared Endophenotypes of Neural Substrates in Bipolar and Major Depressive Disorders.
abstract: Little is known about disorder-specific biomarkers of bipolar disorder (BD) and major depressive disorder (MDD). Our aim was to determine a neural substrate that could be used to distinguish BD from MDD. Our study included a BD group (10 patients with BD, 10 first-degree relatives (FDRs) of individuals with BD), MDD group (17 patients with MDD, 17 FDRs of individuals with MDD), and 27 healthy individuals. Structural and functional brain abnormalities were evaluated by voxel-based morphometry and a trail making test (TMT), respectively. The BD group showed a significant main effect of diagnosis in the gray matter (GM) volume of the anterior cingulate cortex (ACC; p = 0.01) and left insula (p < 0.01). FDRs of individuals with BD showed significantly smaller left ACC GM volume than healthy subjects (p < 0.01), and patients with BD showed significantly smaller ACC (p < 0.01) and left insular GM volume (p < 0.01) than healthy subjects. The MDD group showed a tendency toward a main effect of diagnosis in the right and left insular GM volume. The BD group showed a significantly inverse correlation between the left insular GM volume and TMT-A scores (p < 0.05). Our results suggest that the ACC volume could be a distinct endophenotype of BD, while the insular volume could be a shared BD and MDD endophenotype. Moreover, the insula could be associated with cognitive decline and poor outcome in BD.
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.|Health Service Center, Yamaguchi University Organization for University Education, Yamaguchi, Yamaguchi, Japan.
authors.forename: Toshio
authors.identifier: http://orcid.org/0000-0002-5495-0859
authors.initials: T
authors.lastname: Matsubara
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Matsuo
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Harada
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.|Katakura Hospital, Ube, Yamaguchi, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.|Nagato-ichinomiya Hospital, Shimonoseki, Yamaguchi, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Nakashima
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Watanuki
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.|Egashira Clinic, Kitakyusyu, Fukuoka, Japan.
authors.forename: Kazuteru
authors.initials: K
authors.lastname: Egashira
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Matakazu
authors.initials: M
authors.lastname: Furukawa
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
authors.affiliation: Division of Neuropsychiatry, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D001714:Bipolar Disorder / Q000378:metabolism / Q000473:pathology*; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology; D003072:Cognition Disorders / Q000453:epidemiology*; D003865:Major Depressive Disorder / Q000378:metabolism / Q000473:pathology*; D058068:Endophenotypes; D005260:Female; D066128:Gray Matter / Q000378:metabolism / Q000473:pathology; D006179:Gyrus Cinguli / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007564:Japan / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence