What Might Brain Scans Reveal About Bipolar Disorder?

Bipolar disorder, previously known as manic depression, is an umbrella mental health condition with different subcategories all characterized by fluctuating mood swings. These moods follow a spectrum of “highs” identified as mania or hypomania, periods of emotional balance called euthymia, and lows referred to as dysthymia or depression.

It affects millions of people worldwide, and understanding its underlying mechanisms can be significant in developing effective treatments. One way that researchers are investigating bipolar disorder involves the use of brain scans. This article explores the insights brain scans might provide into this condition.

What is bipolar disorder?

Bipolar disorder, also called bipolar affective disorder, is a serious mood disorder characterized by fluctuations in behavior, emotion, and cognition. Individuals with bipolar disorder experience periods of elevated or depressed mood, which can be accompanied by significant changes in energy levels, sleep patterns, and perception. Bipolar disorder can impact an individual’s emotional health, physical well-being, relationships, and ability to function. It can also arise alongside several different major psychiatric disorders (substance use disorder, anxiety disorders, and oppositional defiant disorder are common comorbidities). 

There are three primary types of bipolar spectrum disorder: bipolar I disorder, bipolar II disorder, and cyclothymic disorder. 

Bipolar I disorder

An individual must have experienced at least one manic episode, which is a period of heightened mood, to be diagnosed with bipolar I disorder. While a manic episode may precede or follow a period of major depression, the existence of depressive symptoms is not necessary for a bipolar I diagnosis. 

Bipolar II disorder

To be diagnosed with this form of bipolar disorder, patients must have experienced both a major depressive and a hypomanic episode. A major depressive episode is a period of low mood marked by sadness, decreased energy, and a loss of interest in activities. Hypomania is a less severe form of mania in which symptoms do not cause significant impairment in everyday functioning. 

Cyclothymic disorder

Also called cyclothymia, cyclothymic disorder is characterized by periods of depressive and hypomanic symptoms that do not meet the criteria for a depressive or hypomanic episode. 

If you believe you’re living with bipolar disorder, a mental health professional can provide you with screenings and determine whether further testing, diagnosis, and treatment are necessary. 

Exploring bipolar disorder and brain scans

Brain scans have become a powerful tool in mental health, providing researchers with a non-invasive way to 

investigate the brain's structure, function, and chemistry. By examining the brains of people with bipolar disorder, scientists might gain insights into the causes and progression of the condition and identify potential targets for treatment.

Here are some reasons why researchers might study the brain for bipolar disorder:

• To identify potential biomarkers

• To understand the underlying neural mechanisms

• To evaluate the effectiveness of treatment options
  
  

Studying the brain for bipolar disorder serves several purposes. Researchers aim to identify potential biomarkers that could be used to diagnose the condition or predict its course. They also seek to understand the underlying neural mechanisms, which could lead to the development of new treatments. Lastly, brain scans could help evaluate the effectiveness of existing treatment options, allowing clinicians to tailor therapies to the needs of their patients.

Types of brain scans used in bipolar disorder research

Several types of brain scans can help study bipolar disorder, each with unique advantages and limitations. Three commonly used scans include the following.

Magnetic resonance imaging (MRI)

• Provides high-resolution images of the brain's structure

• Could allow researchers to examine brain volume, shape, and integrity

• Does not expose participants to ionizing radiation
  
  

MRIs are widely used to generate high-resolution images of the brain's structure. Researchers use these images to examine brain volume, shape, and integrity in people with bipolar disorder. The absence of ionizing radiation makes MRI particularly appealing for research, as it poses minimal risks to participants.

Functional magnetic resonance imaging (fMRI)

• Measures brain activity by detecting changes in blood flow

• Could reveal differences in brain function between individuals with and without bipolar disorder

• May offer insights into how the brain processes information during different mood states
  
  

FMRI is a variation of MRI that measures brain activity by detecting changes in blood flow. This technique allows researchers to identify differences in brain function between people with and without bipolar disorder. By examining how the brain processes information during different mood states, scientists might better understand the neural mechanisms underlying bipolar disorder.

Positron emission tomography (PET)

• Provides information about the brain's chemistry

• Allows researchers to study neurotransmitter systems

• Requires the use of radioactive tracers
  
  

PET scans may offer valuable insights into the brain's chemistry by using radioactive tracers to visualize the distribution of specific molecules. This method enables researchers to study neurotransmitter systems, which are thought to play a significant role in the development and progression of bipolar disorder. However, using radioactive tracers may limit the applicability of PET scans in some situations.

Bipolar brain scan findings

Brain scans have revealed numerous findings in people with bipolar disorder.

Structural abnormalities

• Differences in brain volume and shape.

• Reductions in gray matter volume.

• Abnormalities in white matter integrity.
  
  

Researchers have discovered differences in brain volume and shape between people with bipolar disorder and those without. For example, reductions in gray matter volume have been observed in several brain regions, including the frontal cortex and the hippocampus. 

In a recent study, researchers examined thousands of MRI scans from the Bipolar Disorder Working Group of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium. An ENIGMA Bipolar Disorder Working Group MRI analysis revealed reductions in the thickness of the ventrolateral prefrontal cortex in people with bipolar disorder compared to healthy controls. In addition to significant differences in cortical thickness, individuals with bipolar disorder seem to have abnormalities in white matter integrity, suggesting disruptions in the brain's communication pathways.

Functional abnormalities

• Altered activation patterns in the prefrontal cortex.

• Dysregulation of the amygdala.

• Abnormal functional connectivity.
  
  

Functional brain imaging studies have revealed altered activation patterns in the prefrontal cortex of people with bipolar disorder. This region manages executive functions, such as decision-making and impulse control, which can be difficult for people with bipolar disorder. 

Dysregulation of the amygdala, an area involved in emotional processing, has also been reported. Moreover, abnormal functional connectivity between various brain regions has been observed, potentially contributing to the mood dysregulation characteristic of the condition.

Neurochemical abnormalities

• Alterations in neurotransmitter systems.

• Changes in the distribution of specific receptors.

• Abnormalities in metabolic processes.
  
  

PET studies have provided insights into the neurochemical aspects of bipolar disorder. Alterations in neurotransmitter systems, such as dopamine and serotonin, have been reported. Additionally, changes in the distribution of specific receptors have been observed, potentially influencing how the brain processes information. Abnormalities in metabolic processes, such as glucose metabolism, have also been identified, suggesting that energy production and use might affect the function of bipolar disorder.

Could brain scans help diagnose bipolar disorder?

While brain scans have contributed to our understanding of bipolar disorder, their use as a diagnostic tool remains a topic of ongoing research. Practitioners typically do not conduct a brain scan prior to providing a diagnosis of bipolar disorder, which currently relies on clinical assessment, including the evaluation of symptoms, medical history, and family history. However, researchers are optimistic that brain scans could eventually play a role in the diagnostic process. 

There is evidence that certain brain abnormalities are present even before illness onset. In one 2012 study, researchers found decreased volume in the insula and amygdala of individuals who would eventually be diagnosed with bipolar disorder but had not yet experienced an episode. This suggests that professionals may be able to use these and other neuromarkers to identify individuals who are at increased risk of experiencing bipolar disorder.

Distinguishing bipolar disorder and major depressive disorder

Given their potential as diagnostic tools for bipolar disorder, brain scans could be used to determine whether an individual is living with bipolar disorder or major depressive disorder. Though the clinical symptoms of the two mood disorders are often similar, researchers have found that they differ in the brain abnormalities present in those who develop them. 

Researchers in one study found differences between patients with bipolar disorder and those with major depressive disorder in the functioning of the amygdala following exposure to emotional stimuli. Researchers have also found disparities in neural activity in the hippocampus of individuals with bipolar depression and those with unipolar depression. These findings suggest that brain scans may eventually help professionals differentiate between these two mood disorders when providing diagnoses. 

Effectiveness of online therapy

One benefit of online therapy platforms such as BetterHelp is that, as researchers uncover neural mechanisms and brain imaging abnormalities in bipolar disorders, mental health professionals may be better equipped to tailor therapeutic interventions to address the specific needs of individual patients.

Online therapy also presents a convenient, comfortable option for people to receive therapy from the comfort of their own homes. Finding a therapist’s office can be challenging enough, and there’s no guarantee that a local professional has sufficient experience in treating bipolar disorder. Being able to choose from thousands of licensed therapists in BetterHelp’s directory means you can find someone who may be more suitable to your needs.

A study on the effectiveness of online therapy found that patients could find helpful strategies for managing psychiatric conditions such as depression, anxiety, and bipolar disorder with techniques such as CBT. It was also found to be more cost-effective, providing opportunities for more people to find treatment.