Anterior cingulate volumes associated with trait impulsivity in individuals with bipolar disorder.
OBJECTIVE
Impulsivity is associated with the clinical outcome and likelihood of risky behaviors among bipolar disorder (BD) patients. Our previous study showed an inverse relationship between impulsivity and orbitofrontal cortex (OFC) volume in healthy subjects. We hypothesized that BD patients would show an inverse relationship between impulsivity and volumes of the OFC, anterior cingulate cortex (ACC), medial prefrontal cortex, and amygdala, which have been implicated in the pathophysiology of BD.


METHODS
Sixty-three BD patients were studied (mean +/- SD age = 38.2 +/- 11.5 years; 79% female). The Barratt Impulsiveness Scale (BIS), version 11A, was used to assess trait impulsivity. Images were processed using SPM2 and an optimized voxel-based morphometry protocol. We examined the correlations between BIS scores and the gray matter (GM) and white matter (WM) volumes of the prespecified regions.


RESULTS
Left rostral ACC GM volume was inversely correlated with the BIS total score (t = 3.95, p(corrected) = 0.003) and the BIS motor score (t = 5.22, p(corrected) < 0.001). In contrast to our hypothesis, OFC volumes were not significantly associated with impulsivity in BD. No WM volume of any structure was significantly correlated with impulsivity. No statistical association between any clinical variable and the rostral ACC GM volumes reached significance.


CONCLUSIONS
Based on our previous findings and the current results, impulsivity may have a different neural representation in BD and healthy subjects, and the ACC may be involved in the pathophysiology of abnormal impulsivity regulation in BD patients.
Matsuo
Koji
K
Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 77030, USA.
Nicoletti
Mark A
MA
Peluso
Marco A M
MA
Hatch
John P
JP
Nemoto
Kiyotaka
K
Watanabe
Yoshifumi
Y
Nery
Fabiano G
FG
Monkul
E Serap
ES
Zunta-Soares
Giovana B
GB
Bowden
Charles L
CL
Soares
Jair C
JC
D000328:Adult; D001714:Bipolar Disorder / Q000150:complications*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality; D006179:Gyrus Cinguli / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007175:Impulsive Behavior / Q000209:etiology* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012649:Self Concept; D011795:Surveys and Questionnaires