Common and distinct patterns of grey-matter volume alteration in major depression and bipolar disorder: evidence from voxel-based meta-analysis

Abstract

Finding robust brain substrates of mood disorders is an important target for research. The degree to which major depression (MDD) and bipolar disorder (BD) are associated with common and/or distinct patterns of volumetric changes is nevertheless unclear. Furthermore, the extant literature is heterogeneous with respect to the nature of these changes. We report a meta-analysis of voxel-based morphometry (VBM) studies in MDD and BD. We identified studies published up to January 2015 that compared grey matter in MDD (50 data sets including 4101 individuals) and BD (36 data sets including 2407 individuals) using whole-brain VBM. We used statistical maps from the studies included where available and reported peak coordinates otherwise. Group comparisons and conjunction analyses identified regions in which the disorders showed common and distinct patterns of volumetric alteration. Both disorders were associated with lower grey-matter volume relative to healthy individuals in a number of areas. Conjunction analysis showed smaller volumes in both disorders in clusters in the dorsomedial and ventromedial prefrontal cortex, including the anterior cingulate cortex and bilateral insula. Group comparisons indicated that findings of smaller grey-matter volumes relative to controls in the right dorsolateral prefrontal cortex and left hippocampus, along with cerebellar, temporal and parietal regions were more substantial in major depression. These results suggest that MDD and BD are characterised by both common and distinct patterns of grey-matter volume changes. This combination of differences and similarities has the potential to inform the development of diagnostic biomarkers for these conditions.

A combined VBM and DTI study of schizophrenia: bilateral decreased insula volume and cerebral white matter disintegrity corresponding to subinsular white matter projections unlinked to clinical symptomatology

“…Besides its role in addiction, insula has been recently found to be related to impulsivity, interceptive awareness (13), cognition (14), and emotion regulation (15). Studies with larger samples showed that depression w associated with bilaterally decreased insula volumes (16). In our study, insula volume was found decreased bilaterally in patients with schizophrenia compared with normal controls, consistent with other reports (2,17,18).…”

612. Hippocampal Subfield Volumes in Mood Disorders

“…22 We think that these two moderators may explain why some previous studies found that patients with MDD may have decreased hippocampus compared to patients with BD. 20,21 Both studies did not control for BD type, while Kempton and colleagues were not able to control for the lithium effect. On the other hand, Wise and colleagues performed a meta-regression analysis with lithium use as a moderator, and found that lithium use was not able to explain the between-study heterogeneity.…”

“…These inconsistent results could be related to the use of certain medication with neuroprotective effect, such as lithium and the heterogeneity of BD types in these studies. [19][20][21][22] A recent study, however, reported that patients with BD have reductions in hippocampus according to prior morbidity (number of manic episodes and hospitalization). 23 Regarding MDD, a recent meta-analysis of 32 magnetic resonance imaging (MRI) studies have confirmed the difference in hippocampal volume between patients and controls, but only among patients with MDD whose duration of illness was longer than two years or who had more than one mood episode.…”

The Insula: An Underestimated Brain Area in Clinical Neuroscience, Psychiatry, and Neurology

“…In functional MRI studies, the insular activity was significantly increased during emotional processing [34,35], whereas the insular activity was decreased in restingstate paradigms in patients with major depressive disorder [36,37]. Structural and functional abnormalities of the insula have also been observed in patients with bipolar disorder: in structural neuroimaging studies, gray matter of the insula was consistently reduced in patients with bipolar disorder, including altered developmental trajectories of the insular volume [38][39][40]. In functional MRI studies, no consistent insular activity has been thus far detected in patients with bipolar disorder [41,42].…”