The Neurology of Mood Bias in Bipolar Disorder

Researchers in neurology from the United Kingdom may have identified parts of the brain responsible for mood bias in people with bipolar disorder. If future studies support these findings, this research could lead to improvements in how clinicians diagnose and treat bipolar disorder.

Here’s a quote to think about while reading this article.

“We don’t see things as they are. We see them as we are.”
Anonymous

What Is Mood Bias?

One way to understand mood bias is to consider the “glass half full” metaphor.

In this famous symbolic story, a person pours water into a glass until the liquid reaches the halfway point. An optimist, we’re told, will view the glass as being half full, while a pessimist will see it as half empty.

The amount of water in the glass is, of course, the same for both people. But when the optimist looks at it, they’re thankful for the opportunity to quench their thirst. The pessimist regrets that the glass isn’t filled to the top.

The optimist/pessimist dichotomy assumes that people are consistent in their outlook on life. They either look for the bright side in all situations or perpetually view the world from a cynical perspective.

The concept of mood bias is that our interpretation of the world around us can change significantly according to our current mindset:

• When happy, we’re more likely to perceive events in a positive light.
• When sad or grumpy, we’re more likely toperceive circumstances with disappointment and disdain.

Extending this concept to various mental health disorders:

• A person with generalized anxiety disorder (GAD) may automatically interpret new information as cause for fear or worry.
• Someone with depression may regard their circumstances as proof that they’re incapable of achieving happiness.
• For an individual with posttraumatic stress disorder (PTSD), virtually any external stimuli can trigger a sense of being under siege or otherwise in danger.

Mood bias is one of several terms that describe this phenomenon. Others include interpretation bias, emotional bias, and attentional bias.

Mood Bias and Bipolar Disorder

For people with bipolar disorder, the effects of mood bias can vary depending on which type of episode or symptoms they experience.

To briefly review this condition, le’s lookl at the three types of bipolar disorder:

• Bipolar I disorder involves manic episodes and may also include major depressive episodes.
• Bipolar II disorder includes both hypomanic and major depressive episodes.
• Cyclothymic disorder doesn’t include full episodes, but rather recurrent hypomanic and depressive symptoms for at least two years.

The episodes or symptoms a person with bipolar experiences can include:

• Manic episodes: Periods of elevated mood, inflated self-confidence and self-esteem, increased energy, and heightened motivation. During manic episodes, people commonly exhibit minimal impulse control and often engage in rash or reckless behaviors. Manic episodes last for at least a week.
• Hypomanic episodes: Like manic episodes, but some symptoms may be less intense. A hypomanic episode may only last four days.
• Major depressive episodes: Times of low mood, little to no motivation, diminished self-confidence, lack of energy, and a pervasive sense of hopelessness and helplessness. These symptoms must be present most of the day, most days, for at least two consecutive weeks.

For someone with bipolar disorder, the sudden, extreme swings between mania/hypomania and depression can lead to exaggerated mood bias. For example:

• During a manic episode, a person may interpret a small business opportunity as a can’t-miss path to success. Based on this skewed perception, they may invest substantial amounts of money into a high-risk endeavor or enter an ill-advised contract.
• While in a major depressive episode, they may view someone else’s achievements as evidence that they don’t have what it takes to be successful. This could cause them to abandon a project, turn down a job offer, or engage in acts of unintentional self-sabotage.

When the person moves from one type of episode or symptom to another, their perspective can veer dramatically in the opposite direction, which may cause further instability in their life.

While in a symptom-free period between episodes, the realization of how mood bias undermined their ability to accurately assess a situation can cause significant frustration.

The Neurology of Mood Bias

In July 2024, the journal Biological Psychiatry Open Global Space published a small study on mood bias in bipolar disorder.

Co-authored by Hestia Moningka, DClinPsy, and Liam Mason, PhD, DClinPsy, of University College London, this study used functional magnetic imaging (fMRI) to identify brain areas that influence mood bias and reward prediction in people with bipolar disorder.

In a June 2024 article about this effort, Moningka wrote:

“Our study aimed to find out what goes on in the ventral striatum in 21 participants with bipolar disorder and 21 control participants when momentary shifts in mood occur. We wanted to gauge this down to the order of seconds, in response to monetary rewards.”

The ventral striatum is an area in the center of the brain involved in myriad functions, such as:

• Spatial perception
• Goal-directed behavior
• Reward processing
• Learning
• Stimulus response
• Behavioral strategies
• Environmental contingencies
• Sense of attachment and connection

The 42 participants in this study played a computer game, like roulette, that gave them the chance to win or lose significant amounts of money. While they played the game, fMRI measured how blood flowed through their brain during three stages:

• Choice: The few seconds during which they had to place a virtual wager on which colors they thought would come up on the simulated roulette wheel
• Anticipation: The three to four seconds that the roulette wheel was spinning
• Outcome: When the wheel stopped and they discovered if they had won or lost

The fMRI data allowed Moningka and Mason to identify which brain areas showed increased activity.

Their findings included:

• All participants demonstrated increased brain activity in the anterior insula, which interprets information in terms of cognition, emotions, and motivation.
• When winning, the BD group showed heightened activity in the ventral striatum:
  • The same type of achievement triggered a greater sense of reward among participants with bipolar disorder than for those in the control group.
• Participants with BD showed reduced communication between the anterior insula and the ventral striatum, while these areas functioned in sync among members of the control group.
  • Researchers theorized this connection allows people without bipolar disorder to adapt more effectively when circumstances change.
• Ineffective communication between the anterior insula and the ventral striatum.
  • This may prevent people with BD from moderating their mood in a rapidly changing environment.
  • Researchers theorized this may explain a sudden shift from a manic high to a depressive low after a setback.

Moningka describes the research:

“These findings may help to explain why people with bipolar disorder can get stuck in a vicious cycle where their mood escalates and sometimes causes them to take bigger risks than usual.”

Managing Mood Bias in Bipolar Disorder

These findings could someday lead to improvements in the treatment of bipolar disorder. But that could be many years away. In the interim, how can someone with bipolar disorder minimize the impact that mood bias has on their life?

Three current options are medication, therapy, and training.

Medication

Many people who have bipolar disorder take mood stabilizers. The U.S. Food and Drug Administration (FDA) approved several medications from this category to treat bipolar disorder, including:

• Lithium can limit the impact of acute manic episodes. It may also be beneficial as a long-term maintenance medication.
• Divalproex, or valproic acid, intensifies the effects of gamma aminobutyric-acid (GABA), an inhibitory neurotransmitter. This can also reduce the intensity of acute manic symptoms.
• Carbamazepine is an anticonvulsant that can treat both acute mania and mixed episodes, which involve the simultaneous presence of both manic and depressive symptoms.
• Lamotrigine inhibits the ability to release glutamate, an excitatory neurotransmitter. It also increases the release of GABA. This combination slows the delivery of messages throughout the central nervous system, which can have a calming effect on a person.

None of these medications focus directly on mood bias. But by limiting the duration and intensity of manic or mixed episodes, they may prevent mood bias from exerting such a powerful effect.

Therapy

Many experts consider cognitive behavioral therapy, or CBT, the most effective therapeutic intervention for people with bipolar disorder. CBT, which focuses on the connection between thoughts, emotions, and actions, can directly address the impact of mood bias.

One of the fundamental principles of CBT is that psychological distress results from unhealthy thought patterns, including:

• Negative core beliefs about oneself, one’s environment, and the future
• Dysfunctional assumptions and cognitive distortions
• Automatic negative thoughts

During CBT sessions, patients explore how self-defeating thoughts negatively impact their life. They then learn to adopt healthier ways of interpreting experiences and interactions, with the goal of eliminating or easing future distress.

Training

A computer-based intervention called interpretation bias training (IBT) proved effective at decreasing the effect of mood bias, alleviating depression, and improving functioning among young people with bipolar disorder. Studies indicate that IBT can benefit people with anxiety, depression, and disruptive mood dysregulation disorder.

Using images from the Karolinska Directed Emotional Faces database, IBT helps participants make appropriate judgements of what other people think and feel based on pictures of their faces. Over multiple sessions, the goal of IBT is to shift interpretation of neutral or ambiguous faces from angry to happy.

Find Help for Bipolar Disorder

Crownview Psychiatric Institute offers comprehensive, personalized care for adults experiencing acute symptoms of bipolar disorder and other complex mental health concerns.

Our holistic, integrative approach incorporates therapy, life skills, occupational development, recreation, adjunct services, and case management. We provide all of these services within a dynamic community-like environment.

To learn more about our programming, or to discuss how we can help you or a loved one, please visit our Contact page or call us today.