“Touching the hem of her garment” – A Review of Dr Caroline Leaf at Nexus Church, Brisbane, 2nd August 2015

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 [1]. 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” [2], 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 [3].

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 [4]. 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 [8], 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 [9]. 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 [10], 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.


[1]        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.
[2]        Leaf CM. The gift in you – discover new life through gifts hidden in your mind. Texas, USA: Inprov, Inc, 2009.
[3]        Pitt CE. Hold That Thought: Reappraising the work of Dr Caroline Leaf. 1st ed. Brisbane, Australia: Pitt Medical Trust, 2014.
[4]        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.
[5]        Karatsoreos IN, McEwen BS. Resilience and vulnerability: a neurobiological perspective. F1000prime reports 2013;5:13.
[6]        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.
[7]        Karatsoreos IN, McEwen BS. Psychobiological allostasis: resistance, resilience and vulnerability. Trends in cognitive sciences 2011 Dec;15(12):576-84.
[8]        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.
[9]        Kihlstrom JF. Social neuroscience: The footprints of Phineas Gage. Social Cognition 2010;28:757-82.
[10]      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.

Dr Caroline Leaf and the Myth of the Blameless Brain

Screen Shot 2014-06-06 at 4.10.33 pm

When I came back to Facebook this morning, I found this from Dr Leaf on my feed,

“Don’t blame your physical brain for your decisions and actions. You control your brain!”

Dr Caroline Leaf is a Communication Pathologist and a self-titled Cognitive Neuroscientist. Her post follows her theme of the last couple of weeks, the premise that the mind is the dominant cognitive force, controlling the physical brain, and indeed, all matter. I have written about the Myth of Mind Domination in a previous blog. But Dr Leaf’s latest offering here deserves special attention.

Lets think about her statement in more detail:

“Don’t blame your physical brain for your decisions and actions.”

What Dr Leaf is really saying is that the physical brain has no role in your choices or behaviour whatsoever, because if your physical brain had a role in the decisions and actions you make, it would also carry some blame for your poor decisions and actions.

“You control your brain.”

The question to ask here is, “Which part of ‘you’ controls your brain?” Her answer would be, “Your mind”, although she never says where the mind is. Certainly not in the physical brain or even in our physical body, since “Our mind is designed to control the body, of which the brain is a part, not the other way around.” [1: p33].

So an ethereal, disembodied force is in full control of our physical body, such that our brain has no role in the decisions we make or actions we take. Even at this stage of analysis, Dr Leaf’s statement is ludicrous. But wait, there’s more.

Dr Leaf’s statement puts her at odds with real Cognitive Neuroscientists. Professor Patrick Haggard is the Deputy Director of the Institute of Cognitive Neuroscience at the University College London. He has authored or co-authored over 350 peer-reviewed articles on the neuroscience of making choices. He writes, “Modern neuroscience rejects the traditional dualist view of volition as a causal chain from the conscious mind or ‘soul’ to the brain and body. Rather, volition involves brain networks making a series of complex, open decisions between alternative actions.” [2] Strike one for Dr Leaf.

Dr Leaf’s statement puts her at odds with herself. Two weeks ago when misinterpreting James 1:21, Dr Leaf wrote, “How you react to events and circumstances of your life is based upon your perceptions.” Perception is classically defined in neurobiology as conscious sensory experience [3: p8] although the work of cognitive neuroscientists has shown that perception can also be non-conscious [4, 5]. Either way, perception is based entirely on processing within the brain [3: p6-11]. So one week, Dr Leaf is saying that our brain determines how we behave, and then ten days later, she is telling us that our brain does not determine how we behave. Which is it? Strike two for Dr Leaf.

Finally, Dr Leaf’s statement is borderline insulting to the sufferers of congenital or acquired brain disorders. Would you tell a stroke patient that they shouldn’t blame their physical brain for their immobility, because they’re mind is in control of their brain? What about a child with Cerebral Palsy? Would you tell a mother of a child with Downs Syndrome that their child is having recurrent seizures because they aren’t using their mind properly to control their brain? Dr Leaf is doing exactly that. I find it incredible that she could be so insensitive, given her background as a speech pathologist working with patients with Acquired Brain Injury.

I imagine that her defence would be something along the lines of, “What I meant was, ‘don’t blame your normal physical brain for your decisions and actions. You control your functional brain.’” That sort of explanation would be less insulting to people with strokes or brain injuries, but it then undermines her whole premise. The hierarchy of the brain and the mind doesn’t change just because a part of the brain is damaged.

Besides, changes to brain function at any level can change the way a person thinks and behaves. The classic example was Phineas Gage, who in 1848, accidentally blasted an iron rod through his skull, damaging his left frontal lobe. History records that Gage’s well-mannered, pleasant demeanour changed suddenly into a fitful, irreverent, obstinate and capricious man whose workmates could no longer stand him [6]. Medical science has documented numerous cases of damage to the right ventromedial prefrontal cortex causing acquired sociopathy [7]. How can the mind be in control of the brain when an injury to the brain causes a sudden change in thought pattern and behaviour? Clearly one CAN blame the physical brain for one’s decisions and actions. Strike three. You’re out.

Dr Leaf is welcome to comment here. Perhaps she meant something completely different by her post, although there’s only so many ways that such a statement can be interpreted.

Ultimately, Dr Leaf’s love of posting pithy memes of dubious quality is now getting embarrassing. Being so far behind the knowledge of a subject in which she claims expertise is ignominious. Undermining her own premise and contradicting herself is just plain embarrassing. But to be so insensitive to some of the most vulnerable is poor form. I think she’d be well served by re-examining her facts and adjusting her teaching.


  1. Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:
  2. Haggard, P., Human volition: towards a neuroscience of will. Nat Rev Neurosci, 2008. 9(12): 934-46 doi: 10.1038/nrn2497
  3. Goldstein, E.B., Sensation and perception. 8th ed. 2010, Wadsworth, Cengage Learning, Belmont, CA:
  4. Kouider, S. and Dehaene, S., Levels of processing during non-conscious perception: a critical review of visual masking. Philos Trans R Soc Lond B Biol Sci, 2007. 362(1481): 857-75 doi: 10.1098/rstb.2007.2093
  5. Tamietto, M. and de Gelder, B., Neural bases of the non-conscious perception of emotional signals. Nat Rev Neurosci, 2010. 11(10): 697-709 doi: 10.1038/nrn2889
  6. Fumagalli, M. and Priori, A., Functional and clinical neuroanatomy of morality. Brain, 2012. 135(Pt 7): 2006-21 doi: 10.1093/brain/awr334
  7. Mendez, M.F., The neurobiology of moral behavior: review and neuropsychiatric implications. CNS Spectr, 2009. 14(11): 608-20 http://www.ncbi.nlm.nih.gov/pubmed/20173686


Dr Caroline Leaf – Serious questions, few answers (Part 2)

Yesterday I published the first part of an essay discussing the presentation of Dr Caroline Leaf, Audiologist, Communication Pathologist, and self-titled cognitive neuroscientist, at Kings Christian Church, Gold Coast.

Tonight I want to continue dissecting some of the more pertinent statements that she made, including her view of the mind-brain connection, a smattering of smaller issues, her over-reliance on case studies, and her opinion on the cause and treatment of ADHD.

Tomorrow I will publish the last, and most important part of my essay – That Dr Leaf believes that ‘toxic’ thoughts are sinful, and why this single statement unravels her most fundamental premise.


A large part of her sermon was based on her next premise, that the mind changes the brain, and not the other way around. That is half true. The mind influences the brain, and how we think will have effects on neural pathways within the brain. But for a cognitive neuroscientist to state that the brain does not influence the mind is somewhat concerning.

There are several reasons why her assertion is deeply flawed. For starters, where else does the mind or thought come from other than our neural networks? Thought is built on our neural connections. To say that the brain does not influence thought is like saying that the foundation of a building doesn’t influence the bricks.

There are clinical reasons as well. These come from a few areas – firstly the research that showed that newborn babies (who do not have thought like we have thoughts) are pre-wired for emotions which are refined as we learn. There is no time for neonates to have enough stimulation to form those emotions and reactions if it was from our mind.

Secondly, people with brain injuries or tumours can have personality or mood changes. The most famous was a man in the 1800’s called Phineas Gage, who on 13 September 1848 was packing explosives into rock with a tamping iron (a long, tapered, smooth crow-bar). History says that the explosives sent the tamping iron through his left face and skull, taking a fair chunk of his frontal lobe with it. Depending on who you believe, Gage’s personality changed after his physical recovery, reportedly from a moral, respectful man into a cursing, angry one (Kihlstrom 2010). Some reports of his story were that Gage made an almost full recovery, but assuming that some of the historical record is true, changes to his brain changed his mental function, ie: his thoughts.

Further, I have personally seen two patients with personality changes secondary to brain tumours. The first was a woman in her late 20’s who had six months of worsening anxiety, who did not seek help despite my referrals, until she had a seizure and the diagnosis was made. Then there was the sad case of a girl in her pre-teens who had only two weeks of rapidly escalating sullenness then aggression then violence. Her parents initially thought she was moody, and when they brought her into the Emergency Department they thought she was perhaps in the middle of a psychotic episode. It turned out that she had a very aggressive tumour near her frontal lobe.

It is clear from these cases, and from a basic understanding of the concept of thought, that changes to the brain result in changes to thoughts and the mind, and vice versa.


If I had the time I would like to look at many others issues that she raised, but this isn’t a book. Suffice it to say that she claimed that stress prunes our “thought trees” although the evidence is only in animal models and only related to severe stress (Karatsoreos and McEwen 2011). She also stated that EVERY thought we EVER have is stored in ALL of our cells (so some random fibroblast in my big toe is somehow affected by my thought about tonights dinner), and that ALL our thoughts are stored in our gametes (our sperm and eggs) and are passed down to our 4th generation (but packed, like in a metaphysical zip-lock bag, and only opened if we choose to have the same thoughts.) And here I was thinking that nurture had something to do with learned behaviour.


She also claimed that 55-70% of ASD/ADHD cases are over-referred and the problem is in educational modeling. This one made me mad.

Not even professorial level researchers know exactly what’s going on in ASD/ADHD, so her statement is a brave one to make, especially without referencing her evidence.

She then espoused the party line of ADHD ignorance – that Ritalin is evil and all you need to do is stop their sugar intake and feed them organic foods and give them supplements. Ritalin isn’t perfect, to be sure, but it is the most effective treatment that’s currently available. If dietary measures and educational measures were effective, then ritalin wouldn’t be prescribed. I have never met a parent that has wanted their child on ritalin. Most of them have tried educational/psychological measures or dietary controls first. The reason why ritalin is prescribed is because dietary and psychological interventions on their own do not adequately control the symptoms, or fail altogether.

To confirm that I’m not just having a rant, there is published scientific literature to back me up. In their recently published meta-analysis, Nigg et al (2012) state, “An estimated 8% of children with ADHD may have symptoms related to synthetic food colors.” Eight percent. That’s all! That’s ninty-two percent of children with ADHD (real ADHD, not just rambunctious children with lots of energy) DID NOT have symptoms due to food colourings. Their conclusions: “A restriction diet benefits some children with ADHD. Effects of food colors were notable but susceptible to publication bias or were derived from small, nongeneralizable samples.” In terms of sugar, Kim and Chang (2011) note that, “children who consumed less sugar from fruit snacks or whose vitamin C intake was less than RI was at increased risks for ADHD (P < 0.05).” (emphasis added) The study was only of about 100 children, but the result was statistically significant. It wasn’t a chance effect.

The misinformation she stated as fact from the pulpit promotes scare-mongering and ignorance throughout the church, which has flow on effects. Church members with children with ADHD or ASD will avoid standard medical treatment on Dr Leaf’s advice. When her treatments fail in the majority of cases, those parents will either live with unnecessarily heightened stress because of their child’s poorly controlled condition, or the guilt of using ritalin, all the while believing that they are ruining their childs brain.

This also places the hosting church in a bind. Do they stand behind their guest speaker, or do they support the advice of the medical community? Is their duty of care to the reputation of the guest speaker or to the congregation under their protection? What would happen if Dr Leaf’s advice lead to the death or disability of a person in their congregation? Would they be libel?


Dr Leaf also told a lot of stories of how everyone afflicted came to her and how she healed them all. If you took her at face value, she would have you believe that people with ASD, ADHD, anorexia, OCD, depression etc, just needed a glimpse of their self-worth and their inner gift and they would be cured. While her stories were inspirational, the world of scientific research demands more. If Dr Leaf’s insights are worth more than the hot air she produces when espousing them, then they should be put to the wider research community so they can pass through the fire of peer review. If peer review prove her insights to be valid, I would be happy to apply them and promote them.

Tomorrow, I will publish the last, and probably the most important part of my essay – that Dr Leaf believes that ‘toxic’ thoughts are sinful, and why this single statement unravels her most fundamental premise.


Crum, A. J., P. Salovey and S. Achor (2013). “Rethinking stress: the role of mindsets in determining the stress response.” J Pers Soc Psychol 104(4): 716-733.

Karatsoreos, I. N. and B. S. McEwen (2011). “Psychobiological allostasis: resistance, resilience and vulnerability.” Trends Cogn Sci 15(12): 576-584.

Kihlstrom, J. F. (2010). “Social neuroscience: The footprints of Phineas Gage.” Social Cognition 28: 757-782.

Kim, Y. and H. Chang (2011). “Correlation between attention deficit hyperactivity disorder and sugar consumption, quality of diet, and dietary behavior in school children.” Nutr Res Pract 5(3): 236-245.

Leaf, C. (2009). Who Switched Off My Brain? Controlling toxic thoughts and emotions. Southlake, TX, USA, Inprov, Ltd.

Nigg, J. T., K. Lewis, T. Edinger and M. Falk (2012). “Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives.” J Am Acad Child Adolesc Psychiatry 51(1): 86-97 e88.