Systematic Review of the Neuropathology of Bipolar Disorder
Neuropathological findings in bipolar disorder are not all well-established. Researchers sought to focus on this gap through a systematic review of literature. Of over 5000 publications, 81 met their eligibility criteria for inclusion. It was found that most of the studies had relatively small sample sizes and had a limited amount of brain collections. They also note that not many of the studies have tried to replicate closely to a prior study; however, there have been various positive repeated findings in bipolar disorder that include reduced cortical thickness and glial density in subgenual anterior cingulate cortex, decreased neuronal density in some amygdalar nuclei, and reduced calbindin-positive neuron density in prefrontal cortex.
Harrison PJ, Colbourne L, Harrison CH. The neuropathology of bipolar disorder: systematic review and meta-analysis. Mol Psychiatry. 2020;25(8):1787-1808. doi:10.1038/s41380-018-0213-3