Brain Structural Signature of Familial Predisposition for Bipolar Disorder: Replicable Evidence For Involvement of the Right Inferior Frontal Gyrus
Biological Psychiatry, 07/27/2012
Hajek T et al. – Brain structural changes in bipolar disorder (BD) may result from interplay between illness burden and compensatory processes, which may be enhanced by lithium treatment. The right inferior frontal gyrus volume could aid in identification of subjects at risk for BD even before any behavioral manifestations.Methods
- This is a two–center, replication–design, structural magnetic resonance imaging study.
- First, the authors investigated neuroanatomic markers of familial predisposition by comparing 50 unaffected and 36 affected relatives of BD probands as well as 49 control subjects using modulated voxel–based morphometry.
- Second, the authors investigated effects of long–standing illness and treatment on the identified markers in 19 young participants early in the course of BD, 29 subjects with substantial burden of long–lasting BD and either minimal lifetime (n = 12), or long–term ongoing (n = 17) lithium treatment.
- Five groups, including the unaffected and affected relatives of BD probands from each center as well as participants early in the course of BD showed larger right inferior frontal gyrus (rIFG) volumes than control subjects (corrected p < .001).
- The rIFG volume correlated negatively with illness duration (corrected p < .01) and, relative to the controls, was smaller among BD individuals with long–term illness burden and minimal lifetime lithium exposure (corrected p < .001).
- Li–treated subjects had normal rIFG volumes despite substantial illness burden.