What is the effect of lithium use on the amygdalar volume of adult patients diagnosed with bipolar disorder: a scoping review

Bipolar disorder is a psychiatric condition commonly treated with lithium. This treatment has various biological effects on the brain; however, variability in the areas and types of changes as a result of lithium treatment has resulted in discourse over lithium’s effect. As a result, a comprehensive synthesis is needed to understand lithium’s true neurological effect. This review aims to identify a common result of lithium use in the neurobiology of bipolar patients, specifically in the amygdala, to determine whether volumetric changes in the amygdala are a common effect.

We conducted a preliminary search to identify key search terms across electronic databases, including Google Scholar and PubMed. After screening and application of inclusion and exclusion criteria, 9 cross-sectional studies were identified.

The evidence from these cross-sectional studies showed either an increase or no change in amygdalar volume. While this fails to identify a definite pattern in amygdalar volume changes, it highlights a need for further research to identify sources of heterogeneity and minimize them to ascertain accurate results.

The present review may be used to influence future work concerning neurobiological changes in the amygdala as a result of lithium treatment for bipolar patients by summarizing patterns in the current literature.