Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. She’s currently on tour through Queensland and New South Wales in Australia. Her only stop in Brisbane, my home town, was at Nexus, my former home church. Dr Leaf presented a keynote address at Nexus’s annual Designing Women conference yesterday, and was the guest speaker at their two morning services today.
This morning typified Brisbane winter – cloudless azure skies and a refreshingly cool breeze. In contrast to the air temperature, the hospitality at Nexus was warm and friendly. The worship, soulful and uplifting. I really enjoyed being there.
Then it was Dr Leaf’s turn. It’s amazing just how much misinformation one person can fit into a 30 minute sermon.
The main theme for her sermons was an exposition on the parable of the sower, linking the different ways people receive information, with the story of the woman with the issue of blood. Dr Leaf tried to prove that thought and faith are synonymous by linking verses at the beginning and of the story from the gospel of Mark (5:25-34) – “because she thought, ‘If I just touch his clothes, I will be healed.’” (v28) and “He said to her, ‘Daughter, your faith has healed you. Go in peace and be freed from your suffering.’” (v34).
The link is highly tenuous to start with. Faith is an action, whereas thought is not. We assume that action is always preceded by thought, but it is not. Action does not require thought. Many people act without thinking. This is explained in more detail in my discussion on the Cognitive Action Pathways model.
Though to try and make her explanation more plausible, Dr Leaf padded out the story by telling the Nexus crowds that it was only because the woman had spent 12 years in deep intellectual thinking, meditating on the scriptures, that Jesus could heal her. But that’s Dr Leaf’s conjecture. In truth, no one knows exactly what that woman was doing or thinking in the 12 years that preceded her healing. The Bible never says anything else about the woman, in either version of the story in Mark or Luke (8:43-48), other than “She had suffered a great deal under the care of many doctors and had spent all she had, yet instead of getting better she grew worse” (Mark 5:26). If you have to rely on pure speculation to make your sermon work, then that’s story-telling, not preaching.
The other part of her sermon was an attempt to link the parable of the sower to some neuroscience, specifically the role of hippocampal synaptogenesis in the formation of long term memory (or in English, the changes that take place to nerves in the brain when you hear information and try to remember it).
Dr Leaf interpreted the parable as describing four different types of listener – Listener 1, corresponding to the man who hears the word but the devil takes it away, Listener 2, who hears the word and receives it with joy, but it doesn’t take root, Listener 3 who hears the word but it gets choked out by worries, riches or pleasure, and Listener 4 who hears the word and retains it, and the word produces a harvest.
According to Dr Leaf, these types of listener correspond to different levels of nerve branch growth in the formation of long term memory – Listener 1 doesn’t get past 24 hours before the memory dissipates. Listener 2 only lasts about four to seven days but there isn’t enough emotional salience to continue the growth of the nerve branch. Listener 3 doesn’t get past fourteen days, while the 4th Listener makes it through to a full 21 days, Dr Leaf’s magic number for long term memory.
Sounds great … except that the encoding and consolidation of incoming information is much more complex, and doesn’t rely on just new nerve growth . That, and her numbers are completely arbitrary – with some permanent long term memory encoded in a couple of days. In fact, some long-term memory doesn’t need new synaptic growth at all, just a state of high excitation of the nerve network, known as Long-Term Potentiation, which is reliant on a self-reinforcing chemical cascade (if you want more information on the neurobiology of memory, a good place to start is The Brain From Top To Bottom, maintained by McGill University in Canada).
So the bulk of her sermon was based on biblical conjecture and bad science. Dr Leaf also made a myriad of misleading or mistaken statements: we are wired for love not fear, we learn through the quantum zeno effect, every thought effects every one of our 75 trillion cells, your toxic thoughts poison other people in relationship with you because of quantum physics, and many, many others.
I’ve only really got room for a few extra-special mentions.
1. “The mind controls brain”, and “the non-conscious mind is not bound by time and space”
No actual cognitive neuroscientist would be caught dead making those sort of statements. Saying that the mind controls the brain is like saying that air controls your lungs. The mind is a function of the brain, because when the brain is changed in certain ways, structurally or chemically, the mind changes. This has been known about for over a century, at least as far back as Freud who experimented with cocaine and other “mind-altering” substances.
Therefore if the brain controls the mind, then the non-conscious mind must be bound by the physical universe, which includes space and time. To suggest anything otherwise is just science fiction.
Besides, Dr Leaf herself tells us in her book “The Gift In You” , that our brain controls our mind. Dr Leaf is simply contradicting her own teaching.
2. “75 to 98% of all physical, mental and emotional illness is caused by your thought life.”
This factoid has been thoroughly debunked. If you would like to read more, you can click here or see chapter 10 in my book .
Today, in the second service, Dr Leaf took her fiction a step further and categorically stated that “98% of cancer comes your thought life”. What nonsense! There is no rational evidence for such a ridiculous statement, and I don’t think there is anything more insensitive to cancer victims and their families than to blame then for causing their own cancer.
3. Mental Health
(a) “Mental illness is worse in the last 50 years than ever before”
To try and prove this is true, Dr Leaf flashed up a slide of ‘horrifying statistics” on mental illness. She claims that,
“35-fold increase in mental illness in children”
“Our children are the first in human history to grow up under the shadow of ‘mental illness'”
“Dramatic increase in the number of mentally ill since 50’s … things are worse not better”
“Mental ill health worst its ever been in history of mankind”
Every one of these statements is patently false. Mental illness has been with humankind for ever. The ancient Egyptians were writing about hysteria in women some two thousand years before Christ . It’s only been in the last century or so that mental illnesses have become seen for the biological entities that they are, and not some form of demon possession, criminal behaviour or sexual deviancy.
Dr Leaf was quick to malign the DSM (the Diagnostic and Statistical Manual of psychiatry), suggesting that it’s unscientific. The DSM isn’t perfect, true, but before the DSM, there was even less science to the diagnosis of mental illness. As Dr Leaf herself pointed out, mental illness was previously viewed philosophically or spiritually. There was no consistency in diagnosis and no collection of statistics.
The DSM, for all its faults, gave a framework for mental health diagnosis, but as the science has become more refined, and with increasing awareness and general acceptance of mental health conditions, more people have qualified and/or accepted a diagnosis.
Mental illness has always been there, but now we know what to look for, it’s no longer hidden or ignored.
(b) “Psychotropic medications cause damage to the brain”
While on the subject of mental health, Dr Leaf made the litigation-attracting statement that psychotropic medications (anti-depressants, anti-psychotics) cause damage to the brain. That’s a particularly bold statement to make without citations, or a medical degree, to back it up.
Rather than ‘causing’ damage to the brain, there is scientific evidence that psychotropic medications increase synaptogenesis (the growth of new nerve branches) [5-7], while the NICE guidelines in the UK reviewed the evidence for anti-depressants and found them to be an effective treatment for depression , not harmful as Dr Leaf suggests.
(c) Biological causes for psychiatric illnesses have not been proven.
Dr Leaf also made the preposterous claim that biological causes of psychiatric illness have never been proven, but again, changes to brain structure have been associated with psychiatric symptoms ever since a 13-pound, three-and-a-half foot iron rod went through Phineas Gage’s skull and frontal lobe in 1848, and his personality suddenly changed from pleasant and congenial to depressed and angry . Personality changes represent early symptoms of brain tumours. Use of drugs such as crystal meth can cause paranoia and extreme aggression. You don’t even need to be a doctor to know that, you just need to watch ‘Breaking Bad‘. So examples of the biological basis of psychiatric symptoms are everywhere. There are no grounds for Dr Leaf’s assertion.
4. Toxic thinking causes dementia
Dr Leaf claimed at the end of both sermons that toxic thinking results in the tubular backbone of the new nerve branches becoming contorted, which caused the accumulation of the tau protein in the nerve cells, which was responsible for dementia of every type. This, too, is a fallacy. The accumulation of the tau protein is found only in Alzheimers, not in Lewy Body dementia or in vascular dementia. The abnormal tau protein is likely related to the loss of a intracellular clean-up enzyme system , but Alzheimers is more complicated than just tau protein deposition, and has nothing to do with toxic thinking.
At the conclusion of the second service, I was outside the church when Dr Leaf and her entourage left the church auditorium before the rest of the crowd did, and I approached them to shake her hand and introduce myself. It was the mature thing to do after all. When I was about two metres from her presidential detail, a woman stepped out in front of me, blocking my way.
“You can’t follow them,” she said. “They’re going inside” (ie: hiding in the green room).
“Really?” I said, somewhat caught off guard. “I was simply going to introduce myself.”
“No”, was the firm reply. “You’re not allowed.”
By that time, the presidential detail had disappeared into their fortified sanctuary. The woman with the issue of blood may have got to Jesus, but there was no way I was even getting close to Dr Leaf.
This was a common pattern … Dr Leaf made herself deliberately scarce before and after each service, only coming into the church when the service was well underway, and leaving as soon as she preached, under heavy guard. One has to ask why? What’s she got to be afraid of? Is she so insecure about her teaching that she couldn’t possibly risk speaking to someone and being exposed as intellectually brittle? Or is it that she’s so arrogant as to insist on avoiding the rank-and-file church goer?
The pattern of avoidance of anyone other than her devotees, and her tendency to block anyone who disagrees with her from her social media accounts, would strongly suggest the former, although since she is so insistent on hiding from regular people, it’s really anyone’s guess.
Not that it matters. Dr Leaf could be the nicest person in the world. Her ministry doesn’t rest on her sociability, but its own Biblical and scientific merits, and on that alone, it has been found seriously wanting.
 Citri A, Malenka RC. Synaptic plasticity: multiple forms, functions, and mechanisms. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 2008 Jan;33(1):18-41.
 Leaf CM. The gift in you – discover new life through gifts hidden in your mind. Texas, USA: Inprov, Inc, 2009.
 Pitt CE. Hold That Thought: Reappraising the work of Dr Caroline Leaf. 1st ed. Brisbane, Australia: Pitt Medical Trust, 2014.
 Tasca C, Rapetti M, Carta MG, Fadda B. Women and hysteria in the history of mental health. Clinical practice and epidemiology in mental health : CP & EMH 2012;8:110-9.
 Karatsoreos IN, McEwen BS. Resilience and vulnerability: a neurobiological perspective. F1000prime reports 2013;5:13.
 Duric V, Duman RS. Depression and treatment response: dynamic interplay of signaling pathways and altered neural processes. Cellular and molecular life sciences : CMLS 2013 Jan;70(1):39-53.
 Karatsoreos IN, McEwen BS. Psychobiological allostasis: resistance, resilience and vulnerability. Trends in cognitive sciences 2011 Dec;15(12):576-84.
 Anderson I. Depression. The Treatment and Management of Depression in Adults (Update). NICE clinical guideline 90.2009. London: The British Psychological Society and The Royal College of Psychiatrists, 2010.
 Kihlstrom JF. Social neuroscience: The footprints of Phineas Gage. Social Cognition 2010;28:757-82.
 Tai HC, Serrano-Pozo A, Hashimoto T, Frosch MP, Spires-Jones TL, Hyman BT. The synaptic accumulation of hyperphosphorylated tau oligomers in Alzheimer disease is associated with dysfunction of the ubiquitin-proteasome system. The American journal of pathology 2012 Oct;181(4):1426-35.