Lithium treatment of bipolar disorder increases brain volumes
16 December 2010
Professor Robin Murray and visiting Professor Colm McDonald, collaborated in an international mega-analysis study to examine the brain in bipolar disorder.
Many individual studies have used magnetic resonance imaging (MRI) to look at the volumes of brain structures in bipolar disorder and also the effects of lithium on these. However, these studies have produced conflicting results because they have not had sufficient ‘statistical power’ (the relative value of a set of results compared to other sets of results).
One way to try to find a consensus is to carry out a meta-analysis which combines the effects found in each study, and produces an ‘average’ effect. However, differences in study methodology can lead to meta-analysis results that are hard to interpret. A mega-analysis overcomes these difficulties since the original data from each study is used, rather than relying on ‘averaging’ the findings of the different studies.
This mega-analysis collated original data from around the world to create the largest and most rigorous pooling of data in this area. The researchers were able to show there is an increase in the volume of the right lateral ventricle in bipolar disorder. This is important as it highlights a difference from schizophrenia, where left sided abnormalities are more common.
Furthermore, bipolar patients taking lithium displayed significantly increased hippocampal and amygdala volume compared with patients not treated with lithium and with healthy comparison subjects. The authors believe that this puts beyond doubt an effect of the medication that had long been suspected.
‘Structural Magnetic Resonance Imaging in Bipolar Disorder: An International Collaborative Mega-Analysis of Individual Adult Patient Data’ was published in Biological Psychiatry, to read the paper in full, please follow the link