How Does Bipolar Disorder Affect the Brain?

Medically reviewed by Dr. Mark Hrymoc, M.D.

How does bipolar disorder affect the brain? Bipolar disorder impacts the brain by causing alterations in mood regulation mechanisms, neurotransmitter levels, and neural circuitry. This can lead to significant mood swings, ranging from manic highs to depressive lows. Studies suggest changes in brain volume and activity, particularly in areas responsible for emotional regulation and cognitive function, contributing to the symptoms and challenges associated with bipolar disorder.

Bipolar disorder is a complex mental health condition characterized by extreme mood swings that significantly impact an individual’s life.

These mood fluctuations correlate with profound changes in brain structure and function, affecting emotional regulation, energy levels, and cognitive processes. Fortunately, bipolar disorder treatment can help stabilize mood swings, reduce episode severity and frequency, and improve daily functioning.

This article explores a common question we hear – how does bipolar disorder affect the brain?

How Does Bipolar Disorder Affect the Brain?

Bipolar disorder, marked by intense emotional states from manic highs to depressive lows, affects 5.7 million Americans (DBSA). This disorder is not just a disorder of mood but also a condition deeply rooted in the brain’s functioning and structure.

It involves alterations in brain chemistry, neural response patterns, and even structural changes in areas governing emotion and cognition. These changes can make it hard to regulate emotions and maintain healthy relationships, jobs, academics, and socialization.

So, how does bipolar disorder affect the brain?

Neurochemical Imbalances

Neurotransmitters are chemicals in the brain that send messages to areas in the brain, influencing how the rest of the body responds. Serotonin, dopamine, and norepinephrine are neurotransmitters directly connected to bipolar disorder. When they are out of balance, the messages they send can lead to changes in your mood.

Neurochemical imbalances can make it challenging to do the following:

  • Make good decisions
  • Control impulses
  • Socialize with others
  • Process information
  • Stay focused
  • Resolve conflicts

Research shows when you experience the depressive symptoms of bipolar disorder, neurotransmitters in the brain are low. When the balance shifts and more chemicals are in the brain, you may experience mania symptoms.

Brain Structure Changes

Imaging studies of the brain in people with bipolar disorder show structural changes do occur over time. Findings show a more significant number of manic episodes can lead to faster thinning of the prefrontal cortex. In addition, people with bipolar had a smaller amygdala, hippocampus, and thalamus.

There are other structural changes significant to understanding how bipolar disorder affects the brain. Study results show the following:

  • Decreased gray matter in the prefrontal cortex
  • Overall decreased prefrontal cortical volume
  • Dysfunction in subcortical structures
  • Decreased gray or white matter in the medial temporal structures
  • Loss of gray matter in the prefrontal, parietal, and temporal lobes

Cognitive Functions

Cognitive functions refer to the mental processes that take place in the brain. Bipolar disorder impacts how well the brain functions in specific cognitive areas. It makes it difficult to stay attentive, and some people find it hard to concentrate for extended periods. Bipolar disorder can interfere with the ability to make sound decisions and those with bipolar disorder often make riskier decisions than those not diagnosed with bipolar disorder.

Reduction in planning, problem-solving, and future planning abilities occur due to changes caused by bipolar disorder. Other cognitive function impairments include:

  • Executive functioning
  • Learning
  • Memory
  • Reasoning
  • Visuospatial
  • Slower processing
  • Social perceptions
  • Insight
  • Language
  • Intelligence quotient (IQ)

Emotional Regulation

Studies show people with bipolar disorder have a tougher time regulating their emotions than people without bipolar disorder. One reason is the chemical imbalances that occur in the brain. They have trouble controlling emotions and reactions to those emotions.

Emotional regulation problems may include verbal outbursts, aggressiveness, and loss of relationships due to these behaviors. Someone with bipolar disorder may have extreme reactions to situations that do not bother other people. They become overwhelmed by stress and may use self-harm or substance abuse to cope with their emotions. They may exhibit high anxiety, disordered eating, relationship problems, and suicidal thoughts.

Sleep and Circadian Rhythms

Your circadian rhythm is the body’s internal clock. Daily routines and habits help create a sleep-wake cycle in 24 hours. Bipolar disorder causes disruptions in your circadian rhythm and disturbs your sleep routines, which may be linked to episodes of mania and depression.

A disrupted circadian rhythm can also affect eating, hormones, metabolism, fertility, body temperature, and more. Research shows a decrease in the somatostatin neurotransmitter in the brain’s amygdala, which may be responsible for circadian rhythm problems (bphope). People who do not have bipolar disorder tend to have a rise in somatostatin each morning, while those with bipolar disorder have a reduction in somatostatin.

Bipolar Disorder Treatment Effects

Treatments are available for bipolar disorder. Medications, like lithium, can normalize or rebalance the chemicals in the brain. Lithium is not the only mood stabilizer for bipolar disorder. Doctors may prescribe first or second-generation mood stabilizers, depending on your symptoms.

Someone with more manic episodes may want to try carbamazepine. Other options include antipsychotics, anticonvulsants, and antidepressant medicines. Bipolar disorder medications aim to do the following:

  • Stop the shrinking of gray matter
  • Stabilize moods
  • Prevent future manic or depressive episodes
  • Control symptoms
  • Balance neurotransmitters

Medication is just one element of treatment. When combined with medication, other methods have positive effects on the brain. For example, psychotherapy supports neuroplasticity in the brain, meaning it can be trained to recognize negative thoughts, replace them with positive ones, and, therefore, react positively.

Diagnostic Criteria for Bipolar Disorder

Bipolar disorder is defined by mood swings between emotional highs (mania or hypomania) and lows (depression). The DSM-5 outlines criteria for two main types: Bipolar I and Bipolar II.

Bipolar I Disorder involves at least one manic episode, which may last for a week or require hospitalization. Depressive episodes often occur but are not necessary for the diagnosis.

Bipolar II Disorder consists of depressive and hypomanic episodes, but without the manic episodes seen in Bipolar I. Hypomanic episodes are less severe and do not significantly impair daily functioning.

Differences Between Bipolar I and Bipolar II

The key difference between Bipolar I and II lies in the severity of the manic episodes. Bipolar I is diagnosed when a person experiences at least one manic episode, which can lead to severe disruption in life or need for hospital care. Mania involves highly elevated mood, energy, and unusual behavior that disrupts daily life.

Bipolar II, however, does not involve full-blown manic episodes but includes periods of hypomania. Hypomanic episodes are milder, do not disrupt daily life as much, and must be accompanied by episodes of depression for diagnosis.

Bipolar Disorder Treatment in Los Angeles

Are you looking for a doctor who can provide bipolar disorder treatment in Los Angeles? The Mental Health Center can connect you with psychiatrists in Los Angeles who can help.

Discover innovative and effective bipolar disorder treatment options in Los Angeles, tailored to meet your unique needs and challenges.

At the Mental Health Center, we specialize in connecting you with experienced psychiatrists who are committed to crafting individualized treatment plans, ensuring you receive the compassionate care and support necessary for managing bipolar disorder.

Contact us to learn how we can help you today.


Bipolar disorder alters specific areas of the brain. It can be debilitating, impacting your functioning professionally, academically, and socially.

Bipolar disorder treatment that offers a combination of medication, therapy, resources, and a support network can reduce the effects bipolar disorder has on your brain. You can stabilize your moods and learn how to realize your personal and professional goals.

Contact the Mental Health Center today to discuss bipolar disorder treatment.