Anterior cingulate structure and function in twins with early onset major depression: Genes and environment

Early onset major depressive disorder (MOD) is highly heritable and has been associated with reduced gray matter volume in the subgenual region of the cingulate gyrus. MDD has also been associated with specific cognitive deficits including deficits on attentional tasks. Here we examine if differences in the structure and function of the anterior cingulate are associated with adolescent onset MDD. An epidemioligically ascertained sample of young female twin pairs (15-24y.o.; MZ & DZ) was studied. One or both twins have a lifetime history of MDD. Control twin pairs have no lifetime MDD. Computerized tests of attention including a continuous performance task and N-back tasks are administered. The volume of the anterior cingulate gyrus gray matter is determined based on averaged 3D T1-weighted MPRAGE MRI images (1 mm isotropic voxels) using established stereological image analysis methods with high inter- and intra-rater reliability (ICC > 0.95). Total cerebral volume is included as a covariate for analyses. Left anterior cingulate volume is significantly reduced in twins with MDD in comparison to non-MDD cotwins. Twins with MDD have significant deficits on measures of sustained attention. Potential genetic and environmental contributions to these differences are examined.