Mania-related effects on structural brain changes in bipolar disorder – a narrative review of the evidence

Abstract

Cross-sectional neuroimaging studies show that bipolar disorder is associated with structural brain abnormalities, predominantly observed in prefrontal and temporal cortex, cingulate gyrus, and subcortical regions. However, longitudinal studies are needed to elucidate whether these abnormalities presage disease onset or are consequences of disease processes, and to identify potential contributing factors. Here, we narratively review and summarize longitudinal structural magnetic resonance imaging studies that relate imaging outcomes to manic episodes. First, we conclude that longitudinal brain imaging studies suggest an association of bipolar disorder with aberrant brain changes, including both deviant decreases and increases in morphometric measures. Second, we conclude that manic episodes have been related to accelerated cortical volume and thickness decreases, with the most consistent findings occurring in prefrontal brain areas. Importantly, evidence also suggests that in contrast to healthy controls, who in general show age-related cortical decline, brain metrics remain stable or increase during euthymic periods in bipolar disorder patients, potentially reflecting structural recovering mechanisms. The findings stress the importance of preventing manic episodes. We further propose a model of prefrontal cortical trajectories in relation to the occurrence of manic episodes. Finally, we discuss potential mechanisms at play, remaining limitations, and future directions.

Is brain perfusion correlated to switching mood states and cognitive impairment in bipolar disorder type I? A longitudinal study using perfusion imaging approach

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The relationship between the size and asymmetry of the lateral ventricles and cortical myelin content in individuals with mood disorders

“…Understanding the neurobiological correlates of these disorders may help improve clinical outcomes. One of the structures affected in individuals with mood disorders is the lateral ventricles (Abé et al, 2023;Gray et al, 2020;Hibar et al, 2016Hibar et al, , 2018Ho et al, 2022;Okada et al, 2023;Schmaal et al, 2016). The lateral ventricles are large C-shaped structures that project into the frontal, temporal, and occipital lobes and are responsible for cerebrospinal fluid (CSF) production (Scelsi et al, 2020).…”