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Abnormalities in left inferior frontal gyral thickness and parahippocampal gyral volume in young people at high genetic risk for bipolar disorder

Published online by Cambridge University Press:  12 April 2016

G. Roberts ,
R. Lenroot ,
A. Frankland ,
P. K. Yeung ,
N. Gale ,
A. Wright ,
P. Lau ,
F. Levy ,
W. Wen  and
P. B. Mitchell
G. Roberts
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
R. Lenroot
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Neuroscience Research Australia, Sydney, Australia
A. Frankland
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
P. K. Yeung
Affiliation:
Neuroscience Research Australia, Sydney, Australia
N. Gale
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
A. Wright
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
P. Lau
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia
F. Levy
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Prince of Wales Hospital, Sydney, Australia
W. Wen
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia
P. B. Mitchell*
Affiliation:
School of Psychiatry, University of New South Wales, Sydney, Australia Black Dog Institute, Prince of Wales Hospital, Sydney, Australia Prince of Wales Hospital, Sydney, Australia
*
*Address for correspondence: P. B. Mitchell, School of Psychiatry, University of New South Wales, Sydney, Australia. (Email: [email protected])
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Abstract

Background

Fronto-limbic structural brain abnormalities have been reported in patients with bipolar disorder (BD), but findings in individuals at increased genetic risk of developing BD have been inconsistent. We conducted a study in adolescents and young adults (12–30 years) comparing measures of fronto-limbic cortical and subcortical brain structure between individuals at increased familial risk of BD (at risk; AR), subjects with BD and controls (CON). We separately examined cortical volume, thickness and surface area as these have distinct neurodevelopmental origins and thus may reflect differential effects of genetic risk.

Method

We compared fronto-limbic measures of grey and white matter volume, cortical thickness and surface area in 72 unaffected-risk individuals with at least one first-degree relative with bipolar disorder (AR), 38 BD subjects and 72 participants with no family history of mental illness (CON).

Results

The AR group had significantly reduced cortical thickness in the left pars orbitalis of the inferior frontal gyrus (IFG) compared with the CON group, and significantly increased left parahippocampal gyral volume compared with those with BD.

Conclusions

The finding of reduced cortical thickness of the left pars orbitalis in AR subjects is consistent with other evidence supporting the IFG as a key region associated with genetic liability for BD. The greater volume of the left parahippocampal gyrus in those at high risk is in line with some prior reports of regional increases in grey matter volume in at-risk subjects. Assessing multiple complementary morphometric measures may assist in the better understanding of abnormal developmental processes in BD.

Keywords

Bipolar disordercortical surface areagenetic riskgyral volumeinferior frontal gyrus
Type
Original Articles
Information
Psychological Medicine , Volume 46 , Issue 10 , July 2016 , pp. 2083 - 2096
Copyright
Copyright © Cambridge University Press 2016 

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