MRI Study of Bipolar Sufferers Reveals Structural Differences

Bipolar disorder significantly impacts the lives of approximately 40 million individuals worldwide, yet the underlying brain differences driving this psychiatric condition have historically been challenging to identify.

In the largest magnetic resonance imaging (MRI) study to date, researchers have mapped clear differences between bipolar brains vs normal brains, centering primarily on regions involved in controlling inhibition and emotion.

The research, published in Molecular Psychiatry, provides the first global map of bipolar disorder and how it affects the brain, offering insight into bipolar disorder brain chemistry.

Understanding bipolar disorder and its impact on the brain

Bipolar disorder is characterized by intense mood swings, including episodes of mania and depression. While symptoms have long been clinically recognized, neuroscientific studies using bipolar brain scans can provide deeper insights into structural brain abnormalities.

"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 Ole A. Andreassen, senior author of the study and a professor at the Norwegian Centre for Mental Disorders Research at the University of Oslo.

Bipolar brain vs normal brain: Structural differences

Researchers from the ENIGMA consortium — a global collaboration of thousands of imaging genomics researchers — measured the MRI scans of 6,503 participants, including 2,447 adults diagnosed with bipolar disorder and 4,056 healthy controls. The study identified consistent structural abnormalities in individuals with bipolar brains vs normal brains.

The primary abnormalities include:

• Thinning of gray matter: Most notable in the frontal and temporal regions of the brain, which are associated with inhibition control and motivation.
• Greater deficits in some patient groups: Bipolar disorder patients who had a history of psychosis tended to show greater deficits in the brain's gray matter. 
• Variations based on medication use: Patients who had taken lithium, anti-psychotics and anti-epileptic treatments showed different brain signatures. Lithium treatment, in particular, was associated with less thinning of gray matter.

Bipolar patients tend to have gray matter reductions in frontal brain regions involved in self-control (orange colors), while sensory and visual regions are normal (gray colors).
Credit: ENIGMA Bipolar Consortium/Derrek Hibar et al.

"These are important clues as to where to look in the brain for therapeutic effects of these drugs," said first author Derrek Hibar, an assistant professor at the USC Stevens Neuroimaging and Informatics Institute when the study was conducted. He is now a senior principal data scientist at Genentech.

Bipolar brain scans inform treatment and prevention

The importance of early detection

MRI brain scans provide valuable information for the early detection of bipolar disorder. The mapping of affected brain regions and early identification of brain changes could significantly improve management strategies and patient outcomes.

“This new map of the bipolar brain gives us a roadmap of where to look for treatment effects,” said co-author Paul Thompson, director of the ENIGMA consortium and a professor at the Keck School of Medicine of the University of Southern California. “By bringing together psychiatrists worldwide, we now have a new source of power to discover treatments that improve patients’ lives.”

Personalized treatment approaches

The MRI data from these thousands of brain scans shows notable differences in the brain scans of those with bipolar disorder and healthy controls. But it also highlights that not all bipolar patients’ brain alterations are the same — medication use may have a significant effect on a person’s brain signature.

The finding that those who took lithium generally had less thinning of gray matter may suggest a protective effect of this medication on the brain.

Statistical snapshot: Bipolar disorder today

• Approximately 40 million people worldwide live with bipolar disorder, according to the World Health Organization.
• An estimated 4.4% of US adults will experience bipolar disorder at some point in their lives.
• Bipolar disorder has the highest rate of suicide among all psychiatric conditions, and unlike global suicide rates in the general population, deaths from suicide in bipolar disorder have not declined.

The outlook for future research

Bipolar disorder is among the most debilitating psychiatric disorders, and yet its underlying neurobiological mechanisms are still largely unknown. While the prognosis for individuals with bipolar disorder is mixed, patients routinely struggle with time lost to inappropriate treatments as they are are initially misdiagnosed.

The examination of bipolar disorder-specific structural brain abnormalities is one of the most effective tools available for increasing our neurobiological understanding of the disorder.

In response to these findings, future research will aim to expand on how well different medications can shift or modify these brain measures, with the ultimate goal of creating new avenues to improve symptoms and clinical outcomes for patients.

Other future research efforts may also choose to examine:

• How early intervention strategies might reverse or mitigate structural brain abnormalities.
• Whether bipolar brain scans can predict episodes, enabling preventive measures.
• The development of MRI-based biomarkers for screening individuals at high risk.

MRI studies have revolutionized our understanding of bipolar disorder, clearly delineating structural differences between bipolar brains and normal brains. With continued research, brain imaging promises significant advancements in diagnosis, personalized treatment and preventive care, fundamentally improving outcomes for those living with bipolar disorder.

These insights emphasize the importance of MRI brain scans as an essential component of modern psychiatric evaluation and management.

This article is a rework of a press release issued by the University of Southern California. Material has been edited for length and the content has been updated to provide additional context and details of related developments since the original press release was published on our website. This content includes text that has been generated with the assistance of AI. Technology Networks' AI policy can be found here.