Amygdala volume in depressed patients with bipolar disorder assessed using high resolution 3T MRI: the impact of medication.
MRI-based reports of both abnormally increased and decreased amygdala volume in bipolar disorder (BD) have surfaced in the literature. Two major methodological weaknesses characterizing extant studies are treatment with medication and inaccurate segmentation of the amygdala due to limitations in spatial and tissue contrast resolution. Here, we acquired high-resolution images (voxel size=0.55 x 0.55 x 0.60 mm) using a GE 3T MRI scanner, and a pulse sequence optimized for tissue contrast resolution. The amygdala was manually segmented by one rater blind to diagnosis, using coronal images. Eighteen unmedicated (mean medication-free period 11+/-10 months) BD subjects were age and gender matched with 18 healthy controls, and 17 medicated (lithium or divalproex) subjects were matched to 17 different controls. The unmedicated BD patients displayed smaller left and right amygdala volumes than their matched control group (p<0.01). Conversely, the BD subjects undergoing medication treatment showed a trend towards greater amygdala volumes than their matched HC sample (p=0.051). Right and left amygdala volumes were larger (p<0.05) or trended larger, respectively, in the medicated BD sample compared with the unmedicated BD sample. The two control groups did not differ from each other in either left or right amygdala volume. BD patients treated with lithium have displayed increased gray matter volume of the cortex and hippocampus relative to untreated BD subjects in previous studies. Here we extend these results to the amygdala. We raise the possibility that neuroplastic changes in the amygdala associated with BD are moderated by some mood stabilizing medications.
Savitz
Jonathan
J
Section on Neuroimaging in Mood and Anxiety Disorders, NIH/NIMH/MAP, Bethesda, MD 20892, USA. savitzj@mail.nih.gov
Nugent
Allison C
AC
Bogers
Wendy
W
Liu
Alice
A
Sills
Rebecca
R
Luckenbaugh
David A
DA
Bain
Earle E
EE
Price
Joseph L
JL
Zarate
Carlos
C
Manji
Husseini K
HK
Cannon
Dara M
DM
Marrett
Sean
S
Charney
Dennis S
DS
Drevets
Wayne C
WC
D000328:Adult; D000679:Amygdala / Q000187:drug effects / Q000473:pathology*; D000928:Antidepressive Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D003863:Depression / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000187:drug effects; D011379:Prognosis; D016896:Treatment Outcome; D055815:Young Adult
D000928:Antidepressive Agents