The brains of people with bipolar disorder show distinct differences in regions associated with inhibition and emotion, according to a new magnetic resonance imaging (MRI) study published in the journal Molecular Psychiatry. In addition, these differences may be even more prominent in those with psychosis.
The research was part of ENIGMA (Enhancing Neuro Imaging Genetics Through Meta Analysis), an international consortium which spans 76 centers and includes 26 different research groups around the world. It is led by the Stevens Neuroimaging and Informatics Institute at the Keck School of Medicine at the University of Southern California.
Bipolar disorder is a debilitating psychiatric disorder with serious implications for those affected and their families. However, scientists have struggled to pinpoint neurobiological mechanisms of the disorder, partly due to the lack of sufficient brain scans.
For the study, researchers analyzed the MRI scans of 6,503 individuals, including 2,447 adults with bipolar disorder and 4,056 healthy controls. They also studied the effects of commonly used prescription medications, age of illness onset, history of psychosis, mood state, age, and sex differences on cortical regions.
“We created the first global map of bipolar disorder and how it affects the brain, resolving years of uncertainty on how people’s brains differ when they have this severe illness,” said Dr. Ole A. Andreassen, senior author of the study and a professor at the Norwegian Centre for Mental Disorders Research at the University of Oslo.
The researchers discovered thinning of gray matter in the brains of patients with bipolar disorder when compared with healthy controls. The greatest deficits were found in the frontal and temporal regions, areas that help control inhibition and motivation.
Some bipolar disorder patients with a history of psychosis showed even greater deficits in the brain’s gray matter. The findings also showed different brain signatures in patients who took lithium, anti-psychotics, and anti-epileptic treatments. Lithium treatment was linked to less thinning of gray matter, which suggests it may have a protective effect on the brain.
“These are important clues as to where to look in the brain for therapeutic effects of these drugs,” said Dr. Derrek Hibar, first author of the paper and a professor at the University of Southern California Stevens Neuroimaging and Informatics Institute when the study was conducted.
The researchers plan to conduct further studies to determine how well different medications and treatments can shift or modify these brain measures as well as improve symptoms and clinical outcomes for patients.
Mapping the affected brain regions is also important for early detection and prevention, said Dr. Paul Thompson, director of the ENIGMA consortium and co-author of the study.
“This new map of the bipolar brain gives us a road map of where to look for treatment effects,” said Thompson, an associate director of the USC Stevens Neuroimaging and Informatics Institute at the Keck School.
“By bringing together psychiatrists worldwide, we now have a new source of power to discover treatments that improve patients’ lives.”