Global grey matter volume in adult bipolar patients with and without lithium treatment: A meta-analysis

• Published in: Journal of affective disorders 2018-01, Vol.225, p.599-606
• Main Authors: Sun, Yue Ran, Herrmann, Nathan, Scott, Christopher J.M., Black, Sandra E., Khan, Maisha M., Lanctôt, Krista L.
• Format: Article
• Language: English
• Subjects: Adult; Bipolar disorder; Bipolar Disorder - drug therapy; Diffusion Magnetic Resonance Imaging; Gray Matter - drug effects; Gray Matter - pathology; Humans; Lithium; Lithium - therapeutic use; Meta-analysis; Neuroimaging; Organ Size; Prefrontal Cortex - pathology
• ISSN: 0165-0327; 1573-2517
• DOI: 10.1016/j.jad.2017.08.078

The goal of this meta-analysis was to quantitatively summarize the evidence available on the differences in grey matter volume between lithium-treated and lithium-free bipolar patients. A systematic search was conducted in Cochrane Central, Embase, MEDLINE, and PsycINFO databases for original peer-reviewed journal articles that reported on global grey matter volume in lithium-medicated and lithium-free bipolar patients. Standard mean difference and Hedges’ g were used to calculate effect size in a random-effects model. Risk of publication bias was assessed using Egger's test and quality of evidence was assessed using standard criteria. There were 15 studies with a total of 854 patients (368 lithium-medicated, 486 lithium-free) included in the meta-analysis. Global grey matter volume was significantly larger in lithium-treated bipolar patients compared to lithium-free patients (SMD: 0.17, 95% CI: 0.01–0.33; z = 2.11, p = 0.035). Additionally, there was a difference in global grey matter volume between groups in studies that employed semi-automated segmentation methods (SMD: 0.66, 95% CI: 0.01–1.31; z = 1.99, p = 0.047), but no significant difference in studies that used fully-automated segmentation. No publication bias was detected (bias coefficient = − 0.65, p = 0.46). Variability in imaging methods and lack of high-quality evidence limits the interpretation of the findings. Results suggest that lithium-treated patients have a greater global grey matter volume than those who were lithium-free. Further study of the relationship between lithium and grey matter volume may elucidate the therapeutic potential of lithium in conditions characterized by abnormal changes in brain structure. •Global GMV was significantly larger in lithium-treated vs. lithium-free bipolar patients.•No significant differences in GMV between groups when stratified by mood state.•Difference in GMV between groups in studies that used semi-automated segmentation methods.