Structural Brain Differences in Individuals with Bipolar Disorder: A Developmental Perspective
Milewski, Amy
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2023-03
Abstract
While the existence of bipolar disorder in early adolescence is becoming more widely accepted, the degree of manifestation in childhood is still unclear. This thesis summarizes findings on neurostructural correlates of adult bipolar disorder compared to more limited research on pediatric bipolar disorder. Then we examined the relationship between mania symptoms and brain structure in a large sample of children. We analyzed data from 10,699 9-to-10-year-old children from the Adolescent Brain Cognitive Development (ABCD) Study. We employed structural equation modeling to examine the associations between subsyndromal mania symptoms and cortical grey matter volume and thickness in 68 regions. After correction for multiple comparisons and controlling for age, sex, race/ethnicity, and scanner model, we found that mania was associated with smaller brain volumes in 54 cortical regions (pfdr-values ≤ .048). However, none of these effects survived sensitivity analyses that accounted for socioeconomic status, medication use, in-scanner motion, or total intracranial volume (pfdr-values ≥ .299). There were no significant associations between mania and cortical thickness in any region (pfdr-values ≥ .249). Prior studies have identified structural differences in individuals with bipolar disorder, which is supported by the current study’s results in children. However, these results do not survive when controlling for additional covariates, possibly due to the young age of the current sample. Future studies should associate subsyndromal mania with cortical volume and thickness longitudinally to refine our understanding of the emergence of structural changes during the prodromal stage, which could be leveraged for improved identification and intervention.