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.




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.


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.