Is Depression a Disconnection Syndrome? Meta-Analysis of Diffusion Tensor Imaging Studies in Patients With MDD

• Published in: Journal of psychiatry & neuroscience Vol. 38; no. 1; pp. 49 - 56
• Main Authors: Liao, Yi, MD, Huang, Xiaoqi, MD, PhD, Wu, Qizhu, PhD, Du, Mingying, MD, Lui, Su, MD, PhD, Yue, Qiang, MD, Gong, Qiyong, MD, PhD, Yang, Chuang, MD, Kuang, Weihong, MD, Chan, Raymond C.K., PhD, Kemp, Graham J., MA, DM
• Format: Journal Article
• Language: English
• Published: Ottawa, ON Canadian Medical Association 2013; Joule Inc; CMA Impact, Inc
• Subjects: Abnormalities; Adult and adolescent clinical studies; Anisotropy; Biological and medical sciences; Brain; Brain - pathology; Brain Mapping - methods; Brain research; Corpus Callosum - pathology; Depression; Depressive Disorder, Major - pathology; Development and progression; Diagnosis; Diffusion Tensor Imaging - methods; Evaluation; Female; Fundamental and applied biological sciences. Psychology; Health aspects; Humans; Magnetic resonance imaging; Major depressive disorder; Male; Manic depression; Medical Education; Medical sciences; Meta-analysis; Methods; Mood disorders; Neural circuitry; NMR; Nuclear magnetic resonance; Physiological aspects; Psychiatry; Psychoanalysis; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychopathology. Psychiatry; Research Papers; Studies; Systematic review; China; Mood disorder; Human; Psychology; Evidence-based practice; Depression; Patient; Review; Nuclear magnetic resonance imaging; Evidence-based medicine; Syndrome; Diffusion tensor imaging; Metaanalysis; Medical imagery; Psychopathology; Psychiatry
• ISSN: 1180-4882; 1488-2434
• DOI: 10.1503/jpn.110180

Background Many studies using diffusion tensor imaging (DTI) have demonstrated impaired white matter integrity in patients with major depressive disorder (MDD), with significant results found in diverse brain regions. We sought to identify whether there are consistent changes of regional white matter integrity in patients with MDD, as shown by decreased fractional anisotropy in DTI. Method A systematic search strategy was used to identify relevant whole brain voxel-based DTI studies of patients with MDD in relation to comparison groups. Relevant databases were searched for studies published between January 1994 and February 2011 using combinations of the terms “DTI” or “diffusion tensor;” “whole brain” or “voxel-based;” and “depress*.” Using the studies that met our inclusion criteria, we performed a meta-analysis of the coordinates of decreased fractional anisotropy using the activation likelihood estimation (ALE) method, which detects 3-dimensional conjunctions of coordinates from multiple studies, weighted by sample size. We then used DTIquery software for fibre tracking to locate the fascicles involved in each region. Results We included 11 studies with a combined sample of 231 patients with MDD and 261 comparison participants, providing 50 coordinates of decreased fractional anisotropy. Our meta-analysis identified 4 consistent locations of decreased fractional anisotropy in patients with MDD: white matter in the right frontal lobe, right fusiform gyrus, left frontal lobe and right occipital lobe. Fibre tracking showed that the main fascicles involved were the right inferior longitudinal fasciculus, right inferior fronto-occipital fasciculus, right posterior thalamic radiation and interhemispheric fibres running through the genu and body of the corpus callosum. Limitations The number of studies included was relatively small, and the DTI data acquisition and analysis techniques were heterogeneous. The ALE method cannot handle studies with no significant group differences. Conclusion Voxel-based analysis of DTI studies of patients with MDD consistently identified decreased fractional anisotropy in the white matter fascicles connecting the prefrontal cortex within cortical (frontal, temporal and occipital lobes) and subcortical areas (amygdala and hippocampus). This is strong evidence for the involvement of these neural circuits in the pathology of MDD.