Everything You Need to Know About Chemo Brain 

Written by: Lukas Harnisch-Weidauer
Medically Reviewed By: Roxanne Sholevar, MD

Over two-thirds of patients who receive chemotherapy report experiencing a mental fog during or after treatment. Among patients, this is often referred to as chemo brain. It is known officially as post-cancer cognitive impairment, cancer treatment related cognitive impairment, or cancer-related cognitive change. 

These symptoms can be incredibly frustrating, especially since chemotherapy has physical side effects as well. Dana-Farber psychiatrist Roxanne Sholevar, MD, says those physical impacts can affect how patients see themselves. As a result, their minds become a necessary safe space and extra important. 

“Even subtle impacts on the mind are another attack on someone’s sense of self that has already been attacked so much by cancer and all its consequences,” Sholevar explains. “It is deeply affecting.” 

That’s why it’s crucial to take these experiences seriously, even if they do not seem especially challenging from an outside perspective. 

Fortunately, chemo brain is temporary for most patients and will resolve within 9 to 12 months and. In the meantime, there are many ways to manage and cope with this set of symptoms.  

Over two-thirds of patients who receive chemotherapy report experiencing a mental fog during or after treatment. Among patients, this is often referred to as chemo brain.

What are the symptoms of chemo brain? 

Symptoms of chemo brain can include: 

  • Difficulty finding common words 
  • Difficulty concentrating 
  • Difficulty doing multiple things at once like answering the phone while cooking 
  • Shortened attention span 
  • Weakened short-term memory and difficulty remembering things like names and dates 

These symptoms can overlap with various conditions including anxiety and depression, general fatigue, and other disorders like Alzheimers and dementia. 

“It’s important to look at the big picture,” Sholevar says, since there are several possible causes including chemotherapy. Determining the source of these cognitive symptoms is key to managing them. 

What causes chemo brain? 

Some chemotherapies including cyclophosphamide, adriamycin, 5-FU, and taxol seem to be particularly closely associated with chemo brain, but there are others that can cause the condition. 

Mental health may also be the cause of brain fog. Even in the absence of chemotherapy, depression and anxiety can affect cognition. Research has shown that inflammation caused by depression can erode and disturb connections causing cognitive symptoms. Sholevar also points out that depression pulls more cognitive resources towards depressive thoughts, moving them away from attentiveness. 

People who are being treated for cancer are often taking other medications that can temporarily affect cognition including opioids for pain, benzodiazepines for anxiety, and steroids used after stem cell transplants. Radiation to the brain will also affect cognition.  

Recently, patients have started to use cannabis as well to treat chemotherapy side effects like nausea. According to research though, cannabis can affect short-term memory. 

“That doesn’t mean you shouldn’t take it,” Sholevar says. Cannabis is sometimes the best medication for chemo-induced nausea. However, it’s important to let your care team know that you are using cannabis and to consult with them on the best way to do so. 

How do you manage chemo brain? 

In most cases, chemo brain can be managed successfully. This may require a few changes in lifestyle in addition to the use of coping strategies.  

A psychiatrist like Sholevar can evaluate patients to determine the cause of the fog. Sometimes a particular medication may be the culprit, and there may be an alternative to it, or a possibility to lower the dosage. Chemo brain can also stem from underlying mental health issues, or stress related to treatment, which are all equally crucial to get treatment for. 

Lifestyle adjustments can sharpen the mind and address some of these other issues. Chemo brain is linked to fatigue so it’s important to get enough high-quality sleep. Regular aerobic exercise like walking, running, cycling, or swimming has also been proven to alleviate chemo brain and increase energy levels.  

Socialization and keeping your mind active are also integral.  

“We are social beings, and we know that quality of life is directly related to socialization,” Sholevar explains. Some patients don’t have large social networks and families to lean on, so Sholevar often works with patients to brainstorm ways to get involved in the greater community. This can include taking part in support groups organized by Dana-Farber or connecting to social workers. Other activities like meditation or training your brain with memory games can also be helpful. 

Certain vitamin deficiencies may also be the cause of chemo brain. A physician can evaluate whether you are getting enough vitamin D and B12, which are closely linked with chemo brain. Sholevar often refers patients to the Zakim Center for Integrative Therapies at Dana-Farber, which has a team of dietitians and a host of resources to help patients and families lead healthy lives. 

Finally, if nothing else has worked, a physician may prescribe medication to help with attention. 

Physicians also recommend various coping strategies for patients experiencing memory problems such as: 

  • Sticking to a routine 
  • Using a planner 
  • Using memory “tricks” like finding something that rhymes with a new name or linking an image with information that you hope to remember 

Although this can be difficult, Sholevar says, “It’s important to remain hopeful and encourage your loved ones. We know this condition gets better and that there are things we can do to help it.”