Patients with bipolar disorder who experience manic episodes are more likely to show abnormal brain changes over time, according to one of the largest longitudinal brain imaging studies in its field to date. The study, led by researchers at Karolinska Institutet and University of Gothenburg in Sweden, also confirms links between bipolar disorder and accelerated brain ventricle enlargement.
The findings are published online in the journal Biological Psychiatry.
Bipolar disorder is a psychiatric disorder characterized by recurrent episodes of mania and depression. Previous imaging studies have found structural abnormalities in some regions of the brain of bipolar patients. These abnormalities include lower cortical thickness compared with healthy individuals. The cortex, the outer layer of the brain, shrinks naturally as people age but accelerated cortical thinning has been linked to various brain diseases.
Most previous neuroimaging studies on bipolar disorder have been small and cross-sectional in design, meaning they captured only one snapshot in time. Thus, there has been a lack of large-scale studies that have examined brain changes over time.
In this study, the researchers overcame those shortcomings by collecting magnetic resonance imaging (MRI) data from 14 research centers worldwide to examine changes in the brain over a period of up to nine years. The study involved 1,232 individuals, including 307 bipolar disorder patients and 925 healthy controls.