Structural brain magnetic resonance imaging of limbic and thalamic volumes in pediatric bipolar disorder.
BACKGROUND
Youths with bipolar disorder are ideal for studying illness pathophysiology given their early presentation, lack of extended treatment, and high genetic loading. Adult bipolar disorder MRI studies have focused increasingly on limbic structures and the thalamus because of their role in mood and cognition. On the basis of adult studies, the authors hypothesized a priori that youths with bipolar disorder would have amygdalar, hippocampal, and thalamic volume abnormalities.


METHODS
Forty-three youths 6-16 years of age with DSM-IV bipolar disorder (23 male, 20 female) and 20 healthy comparison subjects (12 male, eight female) similar in age and sex underwent structured and clinical interviews, neurological examination, and cognitive testing. Differences in limbic and thalamic brain volumes, on the logarithmic scale, were tested using a two-way (diagnosis and sex) univariate analysis of variance, with total cerebral volume and age controlled.


RESULTS
The subjects with bipolar disorder had smaller hippocampal volumes. Further analysis revealed that this effect was driven predominantly by the female bipolar disorder subjects. In addition, both male and female youths with bipolar disorder had significantly smaller cerebral volumes. No significant hemispheric effects were seen.


CONCLUSIONS
These findings support the hypothesis that the limbic system, in particular the hippocampus, may be involved in the pathophysiology of pediatric bipolar disorder. While this report may represent the largest MRI study of pediatric bipolar disorder to date, more work is needed to confirm these findings and to determine if they are unique to pediatric bipolar disorder.
Child and Adolescent Neuropsychiatric Research Program, Cambridge Health Alliance/Mystic Center, 1493 Cambridge Street, Cambridge, MA 02139, USA. jfrazier@challiance.org
Jean A
JA
Frazier
Sufen
S
Chiu
Janis L
JL
Breeze
Nikos
N
Makris
Nicholas
N
Lange
David N
DN
Kennedy
Martha R
MR
Herbert
Eileen K
EK
Bent
Vamsi K
VK
Koneru
Megan E
ME
Dieterich
Steven M
SM
Hodge
Scott L
SL
Rauch
P Ellen
PE
Grant
Bruce M
BM
Cohen
Larry J
LJ
Seidman
Verne S
VS
Caviness
Joseph
J
Biederman
D000293:Adolescent; D000367:Age Factors; D000553:Ambulatory Care; D001284:Atrophy / Q000473:pathology; D001714:Bipolar Disorder / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D002648:Child; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008032:Limbic System / Q000473:pathology* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D011569:Psychiatric Status Rating Scales; D012737:Sex Factors; D013687:Telencephalon / Q000473:pathology; D013788:Thalamus / Q000033:anatomy & histology / Q000473:pathology* / Q000503:physiopathology