Mental Fog, Chemotherapy Side Effect, Is Real and Often Treatable


Not long ago, doctors were often skeptical when cancer patients who had undergone chemotherapy complained that they were mentally foggy; unable to plan a week’s worth of meals or organize their finances as they could before. Patients called this side effect “chemobrain” and were frustrated by the lack of recognition – or suggested remedies – from their physicians.

Now, the problem is better defined, and physicians recognize that 50 to 60 percent of individuals experience these difficulties during or after chemotherapy. Recent studies have pinpointed changes in the brains of such patients.

Some scientists have adopted a more formal term – post-cancer cognitive impairment (PCCI) – to describe this group of symptoms, which include memory lapses; difficulty concentrating, planning ahead, organizing, and multitasking; and slow mental processing.

“Studies suggest that PCCI will resolve in most patients within nine months, but some patients do experience symptoms for years afterward,” notes psychiatrist Fremonta Meyer, MD, of Dana-Farber’s Center for Psychosocial Oncology and Palliative Care Research.

main with chemo brainWhen she sees patients with complaints of “chemobrain,” Meyer says she looks for additional factors that might be affecting cognition, such as poor sleep, depression, anxiety, or medications other than chemotherapy.  “I’ve had a few patients who were concerned about chemobrain, but their symptoms improved after they stopped taking a particular medication,” she says.

Managing “chemobrain” requires several approaches, says Meyer. Among them:

  • Reduce fatigue with improved sleep hygiene and aerobic exercise.
  • If the problem is severe, talk to your physician about a referral for neuropsychological testing, and if necessary, brain fitness or cognitive rehabilitation programs.
  • With guidance from your physician, consider medications that stimulate thinking and alertness.
  • Avoiding multitasking. Make use of daily planners, smart phones, to-do lists, and other organizers.
  • Adopt and follow routines – for example, you might choose a place to keep  commonly lost objects, and always put them there.
  • Maintain social connections.

Meyer reassures her patients that chemobrain doesn’t usually get worse once it develops. Moreover, it is not a sign of dementia, nor does it increase the risk of dementia.

Watch Dr. Meyer’s presentation on managing chemobrain.


  1. I was fired from my job because of chemobrain. I at the time was juggling single parenthood, financial crisis and of course almost dying. I often wondered if it was the poor sleep, the depression or what. But I will tell you that a psychiatrist put me on Concerta 1 month post chemo and within a week, it felt like the fog was completely gone…I have often wondered, as a psychologist myself, if this should be explored…the use of ADD drugs for this…

  2. It’s so incredibly annoying that the existence of something is not considered real until the doctors say so. While being in treatment with chemo I experienced moments while playing the piano (I am an accomplished pianist) in which I had no idea how to read music. It would happen just for one beat and then again a few measures later. That was over five years ago. I didn’t bother discussing any more side effects with my oncologist after seeing that glassy eyed, patronizing look. Instead i went to an acupuncturist and took care of it myself.

    • Dear Carol —

      I’m so sorry to hear you have struggled with this side effect. It’s good to hear that you have been able to find some relief in acupuncture.

      You may be interested to know that last spring, the National Comprehensive Cancer Network (NCCN) added chemobrain to its cancer survivorship guidelines. Although there is no specific screening tool for chemobrain, the NCCN’s provided some guidance for clinicians.

      Wishing you all the best!

  3. In 2003 I went through 3 months of chemotherapy.Prior to chemo I was a ”star” in my field of employment, Healthcare Information Systems. I received numerous awards and letters of accolades from clients.After chemotherapy up until 2014 I was fired from 5 jobs due to chemotherapy. I was informed by my Physician that there would be a strong possibility that I would not be able to go back to the career I built for more than 20 years due to what my doctor described as ”chemo brain”. I refused to accept what he was telling me. Consequently I experienced a lot of emotional pain and humility getting fired from 5 jobs in 10 years. I was just about to throw in my hat and enroll into on-line college course for a new career that was not as technical as my original career in Healthcare IS. That was about the time I went in for my yearly check up and was diagnosed with Stage IV breast cancer which metastasis to my bones.I am now on disability. I now spend quality time with friends and family as well as volunteer work with cancer patients as my focus.In some ways Cancer is a gift to show you not to be a workaholic and make better decisions on work and family balance. It really hit home when I read the quote ”on your deathbed you will not be asking to see your awards from employers, you will want your loved ones around you”…lesson learned and I am living to accomplish this motto.

    • Dear Lyndsey —

      Thank you so much for connecting with us and sharing your story. I am so sorry to hear about the health trouble you have faced, but you seem to have the right attitude as you continue this journey. Wishing you all the best.

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