Monday, June 4, 2012

How Stress Affects Memory

We know from several studies now that some patients show cognitive decline just prior to cancer treatment.
And as I’ve written in other posts, this has led to a whole new realm of study looking at how inflammatory molecules, called “cytokines,“ may be contributing to post-diagnosis problems with memory and concentration and word retrieval, etc.
But there are other theories as well. We discuss one in our book that relates to stress (depression also) and how it may affect memory (a recent study in the Journal of Clinical Psychology supports the stress-memory connection). Fear and anxiety can produce a debilitating drop in energy and mood, and cloud how we think. So it’s good to understand how stress affects our minds and find ways to cope, whether you’re dealing with cancer or not.

The material below is adapted from our book, Your Brain After Chemo. I hope it helps.

Fight or Flight?
Short-term stress creates a chemical reaction in our bodies known as the fight-or-flight response. It’s a reaction that is so primitive and hardwired into our genetic makeup that from the beginning of human existence it has helped ensure our survival. This response helped our ancestors defeat or run from jungle predators. Physically what happens is, our pulse quickens. We breathe harder. Our pupils dilate. Our livers release more glucose into our blood to provide extra energy to our muscles and brain.

Fighting Tigers
These kinds of short-term stresses are our physical and emotional tigers and have stayed with us through evolution. We release these stress chemicals when someone cuts us off on the highway and when our “Type A” personality kicks into overdrive. When the threat disappears, we can relax. Our brain calls off its “red alert.” Our sympathetic nervous system slows. Our parasympathetic nervous system resumes its maintenance functions.

What Color is Your Cortisol?
But there are also long-term stresses that may damage the brain and the immune system over time. This happens when our brains remain on “orange alert,” when we feel helpless, perhaps when we have been ill and when worry and grief consume us. When that happens, we release another set of hormones, the best studied of which is called cortisol. We release this hormone from the cortical (outer shell portion) of our adrenal glands and pump it into our bloodstream.

We even know from blood and amniotic fluid samples of pregnant women who are stressed that high amounts of cortisol will affect the neuroendocrine systems of their developing fetuses. Biologically, these babies will be more sensitive to stress.

Over the long term, cortisol suppresses our immune systems, and we become less able to fight off infections. Too much cortisol will also directly affect the brain . . . for example, cortisol can shrink cells in the hippocampus, a part of the brain that is necessary for forming and accessing memories.

Aiming for Calm
What’s interesting is there’s also a relaxation response which returns our bodies to a normal state. So relaxation techniques such as meditation (we include an exercise in our book), physical exercise, qi gong, yoga, talking about your stressors with a friend or a psychotherapist, help break the momentum. For more on this, see our chapter, “Fear, Stress, and Mindfulness.”


  1. Idelle,
    I've enjoyed learning about your work and wish I could attend the NCI conference next week to hear you and meet you in person.

    I've always wondered as well about the incidence of chemobrain in previously depressed women; and those who are in peri-menopause. These are a lot of factors to ferret out.

    Thanks for great information,

  2. Hi Jody, I wish you could be there too. And thanks so much for the gracious mention on #BCSM tonight.

    I wonder about the pre-depression too, that's a very interesting question. I also wonder about how hormones may or may not play a role with women in peri-menopause. There is so much to consider!

    Looking forward to getting to know you better!