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Chemo Brain as a Side Effect of Chemotherapy

'Why Can't I Think Clearly After Chemo?'


Updated May 16, 2014

Chemo brain is a relatively new term that refers to the cognitive changes that can occur as a side effect of chemotherapy. Many people who have gone through chemotherapy notice some temporary changes in their memory or thinking process. It might be harder to do two things at the same time, the car keys disappear, and the event you just read about in the newspaper just doesn’t seem to stick in your memory. The jury is still out on how common chemo brain is or what the causes are, but we are learning more about this annoying symptom, and what you can do to cope as you recover from chemotherapy.


Symptoms of chemo brain have been described by some cancer survivors as “brain fog.” In his blog about his life with cancer the late Leroy Sievers shared his experience with chemo brain. He described these symptoms as: “It’s a little bit like the feeling you get when you’ve had one or two drinks too many, and you don’t want to be drunk. You will try to talk yourself into clarity but it doesn’t always work.” Symptoms of chemo brain may include:
  • Difficulty concentrating and thinking clearly
  • Trouble performing more than one task at a time (difficulty multitasking)
  • Decreases in memory – especially visual and verbal memory, such as problems remembering things that were said in a conversation or an item written on a grocery list
  • A shortened attention span
  • Becoming easily confused, especially when learning new information
  • Feeling disorganized

What Causes Chemo Brain?

Side effects of cancer treatment as well as the cancer itself can contribute to many of the symptoms we describe as chemo brain. Anemia, sleep changes, depression, fatigue, and anxiety over a diagnosis of cancer can all affect your concentration. But chemotherapy may also play a direct role in these symptoms. Neuropsychological testing has shown that changes in the brain do occur during chemotherapy, and research is ongoing looking at the ways in which chemotherapy affects the brain. How much these symptoms are due to the rigors of cancer treatment, and how much is directly attributable to chemotherapy remains to be seen. What is most important is that cancer survivors get the support they need to cope with symptoms they experience following chemotherapy.


Chemo brain can be very frustrating both for those who are living with cancer, and their loved ones who are trying to support them. Feeling disorganized can affect your quality of life and ability to make decisions. For those who are working or going to school, difficulties concentrating can be challenging on top of the fatigue most people already experience following treatment.


The first step in coping with chemobrain is to understand that these symptoms are not “all in your head.” Give yourself permission to take extra time thinking through problems. For most people, symptoms of chemo brain improve significantly over time. Some tips that have helped others cope include:
  • Keep a calendar handy, and write down important dates and appointments
  • Get enough sleep
  • Exercise both your body and mind. Some people find that activites like soduko or crossword puzzles help to challenge their minds and organize their thoughts
  • Look at ways to manage stress in your life
  • Focus on a single task. Don’t try to do too many things at once
  • Eat a healthy diet. A diet rich in vegetables can give your brain a boost

When to Talk to Your Doctor

If you are experiencing any symptoms of chemo brain, talk with your oncologist. She will want to check for any other conditions that are causing or contributing to your symptoms, and review your treatment plan. If your symptoms are interfering significantly with your day-to-day life, she may recommend that you see a neurologist or psychologist to conduct a more in depth evaluation and make suggestions on ways you can cope at this time.


American Cancer Society. Chemo Brain. 06/13/08. http://www.cancer.org/docroot/MBC/content/MBC_2_3x_Chemobrain.asp

Nelson, C. et al. Chemotherapy and cognitive deficits: mechanisms, findings, and potential interventions. Palliative and Supportive Care. 2007. 5(3):273-80.

Taillibert, S. et al. Chemobrain: is systemic chemotherapy neurotoxic. Current Opinions in Oncology. 2007. 19(6):623-7.

Weiss, B. Chemobrain: a translational challenge for neurotoxicity. Neurotoxicology. 2008. 891-8.

Whitney, K. et al. Is “chemobrain a transient state? A prospective pilot study among persons with non-small cell lung cancer. The Journal of Supportive Oncology. 2008. 6(7):21.

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