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

Introduction: 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.

Methods: 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.

Results: 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.

Conclusions: 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.