How Multiple Myeloma Affects Your Brain

Medically Reviewed by Sabrina Felson, MD on June 25, 2022
5 min read

If you have poor mental health symptoms or feel like your brain isn't as sharp as it used to be, you’re not alone. About 25% of people with multiple myeloma report serious mental distress and depressive symptoms.

These mental health issues may be due to living with the illness or health problems that you may get because of myeloma medicines or treatment.

If you have multiple myeloma, you might have what experts call altered mental status (AMS). AMS describes disorders or symptoms that suggest the brain isn’t working properly. People with altered mental status have symptoms like:

  • Confusion
  • Trouble focusing
  • Slowness
  • Seeing things that aren’t there
  • Restlessness
  • Boredom
  • Aggression
  • Low interest in activities
  • Disorganized thinking
  • Memory problems
  • Coma

If you have symptoms of AMS, it might be a side effect of your treatment. Also, myeloma complications like kidney damage, frequent infections, high blood calcium, and more may change how well your brain works.

Like other rare conditions without a cure, multiple myeloma has unique challenges that may worsen your mental health.

A study that looked at well-being issues in people with myeloma pointed out that many patients don't feel properly cared for. These patients also report:

  • Sleep problems
  • Feeling anxious and depressed
  • Tiredness
  • Pain
  • Memory problems
  • Worry related to their health
  • Nerve damage symptoms like weakness and numbness

These mental issues may affect treatment outcomes. A 2018 study suggests that thinking problems are tied to lower survival rates in people with blood cancer.

The researchers put forward a few reasons why having poor thinking skills limits survival:

  • You may struggle to remember when to take your medications and go to appointments.
  • It may be tough to drive to your appointments safely.
  • You may find it hard to follow complex conversations or instructions that could benefit your health.

The researchers advise doctors to test people with blood cancer for problems with their thinking skills to better care for them.


About 20% of cancer patients get hypercalcemia during their illness. Of all the other cancers, multiple myeloma causes this complication the most.

Myeloma cells destroy bone, which releases calcium, a condition called hypercalcemia.

Hypercalcemia can cause bone pain and bone loss, nausea and vomiting, kidney stones, constipation, and fatigue.

Evidence also suggests that hypercalcemia can lower brain function and mental health. If you have it, you may have symptoms like:

  • Anxiety
  • Depression
  • Poor thinking skills
  • Confusion
  • Low energy
  • Fatigue
  • Psychosis, a condition that causes you to feel, see, or hear things that aren’t real
  • Coma


Myeloma cells produce excess abnormal proteins, called paraproteins, in the bone marrow that can cause your blood to become so thick that it flows sluggishly in your body, a condition called hyperviscosity.

About 2%-6% of people with multiple myeloma have hyperviscosity. This condition is serious and can cause harm to your physical and mental health.

Hyperviscosity may affect your brain function, causing you to have symptoms like:


Hyperammonemia is a condition in which the blood has high ammonia levels. Ammonia is a toxin that attacks the nervous system and causes nerve cells to stop working. This condition occurs in rare cases of multiple myeloma. But when it does, it can be fatal.

Hyperammonemia can cause ammonia to go to the brain. When this happens, you might have symptoms of brain troubles, such as:

  • Memory problems
  • Trouble paying attention
  • Crankiness
  • Headache
  • Confusion
  • Brain swelling, or brain edema
  • Intracranial hypertension, high pressure around the brain
  • Seizures
  • Poor coordination
  • Too much sleepiness
  • Coma

Kidney failure

Abnormal proteins from myeloma cells can also damage the kidneys. People with kidney failure may have symptoms like depression, anxiety, suicide, panic, and delirium.

Kidney failure can also cause you to have uremia. With uremia, a kidney can’t filter out waste because it no longer works well, so the waste stays in the blood.

Uremia can also affect how the brain works. When this happens, you may have symptoms like

In serious cases, uremia can cause seizures, coma, and death.


Myeloma and treatment for myeloma can weaken your immunity, making the body prone to many infections. People with myeloma are most prone to infections in the first month after diagnosis. These infections are a serious problem and a leading cause of death in people with myeloma.

They may happen in different body parts, like the respiratory tract, urinary tract, skin, heart, bones, joints, and brain with meningitis.

Meningitis is an infection of the fluid and membranes (meninges) surrounding your brain and spinal cord. It may cause symptoms like:

Meningitis can cause death in a few hours. People who recover may live with problems like hearing loss, learning disabilities, and brain damage.

You may also have brain problems from the side effects of medications you may be on. Immunomodulatory drugs (IMiDs) used in treating multiple myeloma may cause you to have issues with your thinking and mood swings.

For instance, your doctor may prescribe bortezomib combined with corticosteroids in cases where you’re not responding well to regular treatment.

Corticosteroids can cause mental disorders like mania, aggression, depression, delirium, psychosis, and suicidal thoughts. Bortezomib with dexamethasone, a corticosteroid, has been shown to cause symptoms like sleep deprivation, high self-esteem, and excessive talking in patients in their first week of treatment.

Chemotherapy, another treatment for multiple myeloma, can also cause side effects, generally called “chemo brain” or “chemo fog.”

Chemo fog can make you have symptoms of thinking problems like:

  • A hard time remembering things
  • Confusion
  • Problems concentrating
  • Poor attention span
  • Trouble multitasking
  • A hard time learning

These symptoms happen in 75% of patients receiving chemotherapy and 35% after chemotherapy.

Autologous hematopoietic stem cell transplant is a treatment done after high-dose chemotherapy. Here, a bone marrow transplant specialist replaces cells damaged from chemotherapy with healthy ones. Doctors commonly prescribe this treatment for people under 70 who have just been diagnosed with multiple myeloma.

People who go through this procedure have been shown to have a hard time sleeping and brain problems like poor memory, a hard time concentrating or paying attention, mental slowness, and others.

Multiple myeloma can affect your brain in many ways. If you’re having symptoms that suggest you might be having brain problems, talk to your doctor so that you can get the necessary treatment.