Stress! Believe the media and seemingly every disease known to man is in some way linked to it. Heart disease = stress. Cancer = stress. Flatulence = stress.
Dr Caroline Leaf, Communication Pathologist and self-titled cognitive neuroscientist, has been of a similar opinion for the last couple of decades. Dr Leaf must have been kind enough to read my book, because after teaching for the last fifteen years that stress is toxic, a subtle shifting under the weight of evidence has appeared.
In her 2009 book , Dr Leaf wrote,
“The result of toxic thinking translates into stress in your body.” (p15)
“Stress is a global term for the extreme strain on your body’s systems as a result of toxic thinking.” (p15)
“Stress is a direct result of toxic thinking.” (p29)
“These stages of stress are scientifically significant because they illustrate how a single toxic thought causes extreme reactions in so many of our systems.” (p39)
In 2013, her position on stress hadn’t really changed that much: “Even a little bit of these negative levels of stress from a little bit of toxic thinking has far-reaching consequences for mental and physical health”, and “The association between stress and disease is a colossal 85 percent.” [2: p36-37]
Again in her 2009 book , Dr Leaf devotes an entire chapter to the alleged effects of the toxic stress pathway on our body (chapter 4, p39-43).
Now in her latest social media update, tucked in amongst the gratuitous selfies and holiday snaps, comes something that’s actually about mental health: “Stress does not kill… is good for us! Its our negative reactions to stressful events that pushes into negative stress…and this is what kills! Sistas 2014 NZ”
The problem for Dr Leaf is that any stress, whether it’s caused by our “negative” reactions or not, doesn’t actually kill us.
There is a phrase used in science, “Correlation does not equal causation”. This simply means that just because two things occur together, one doesn’t necessarily cause the other. For example, do my red watery eyes cause my hives? They always appear together, but they don’t cause each other. The common element that causes both of them is actually the cat that I’ve just patted.
Just because stress is correlated with certain illnesses does not mean that stress causes or contributes to those illnesses. In fact, one of Dr Leafs own pivotal references, an article by Cohen and colleagues in the Journal of the American Medical Association in 2007, discussed the weakness of assuming that stress causes most diseases. As they say, “Although stressors are often associated with illness, the majority of individuals confronted with traumatic events and chronic serious problems remain disease-free.” 
Even if it were true that it how we react to stress contributes to the outcome of that stress, Dr Leaf’s statement about our killer reactions incorrectly presumes that both how we cope with stress, and the physical outcome of stress are the result of our choices.
Our levels of stress, and the way we cope with our stress, is mostly caused by our genetics. Some people will be naturally less stressed, and some people will be naturally better at coping with stress (see chapter 5 of my book  for a full discussion on the science of resilience). Just because you’re more prone to stress doesn’t mean that it’s all down to your bad choices. Assumptions like these only add to your already high levels of stress.
That’s not to say that we don’t have a way to improve our responses. For those of us at the stressed end of the spectrum, successful psychological therapies such as Acceptance and Commitment Therapy will help to improve our coping, and certainly have been shown to improve (not cure) mental illnesses like anxiety and depression, and other chronic conditions like chronic pain (see  for a review).
ACT and other modern psychological therapies recognise that trying to change our thoughts doesn’t make any difference to how we cope. So like I said before, it’s partly true that how we react to normal life experience will help us live full and productive lives, but it’s not about fighting or changing our thoughts. It’s about being mentally flexible enough to make room for our thoughts and fears and move forward towards meaningful action. I’m sure that the ladies at ‘Sistas 2014’ wouldn’t be hearing that from Dr Leaf.
Anyways, I’m glad that Dr Leaf is changing her tune on stress, but there’s still more room for change before she meets up with current scientific understanding.
For an in-depth review of the teachings of Dr Leaf, visit http://www.smashwords.com/books/view/466848 where you can download a free copy of “Hold That Thought: Reappraising the work of Dr Caroline Leaf.“
- Leaf, C., Who Switched Off My Brain? Controlling toxic thoughts and emotions. 2nd ed. 2009, Inprov, Ltd, Southlake, TX, USA:
- Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
- Cohen, S., et al., Psychological stress and disease. JAMA: the journal of the American Medical Association, 2007. 298(14): 1685-7
- Pitt, C.E., Hold That Thought: Reappraising the work of Dr Caroline Leaf, 2014 Pitt Medical Trust, Brisbane, Australia, URL http://www.smashwords.com/books/view/466848
- Harris, R., Embracing Your Demons: an Overview of Acceptance and Commitment Therapy. Psychotherapy In Australia, 2006. 12(6): 1-8 http://www.actmindfully.com.au/upimages/Dr_Russ_Harris_-_A_Non-technical_Overview_of_ACT.pdf