Dr Caroline Leaf and the Myth of the Chemical Imbalance Myth

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There are lots of medical myths that people believe.

“I have acne because I eat too much chocolate, or my face isn’t clean enough”

“Stomach ulcers are because of stress”

“I coughed up some yellow phlegm, so I must need antibiotics right?”

“My baby’s fevers are because of teething.”

Is the “chemical imbalance” theory one of them?

Dr Leaf is a communication pathologist and self-titled cognitive neuroscientist. A couple of weeks ago she opened a proverbial can of worms by quoting the out-spoken Peter Gøtzsche, claiming that psychiatric drugs are the third leading cause of death after heart disease and cancer. This did not go down well, and Dr Leaf had to issue three separate statements on social media to try and justify herself and attempt to rescue her rapidly deteriorating credibility.

Not that she issued an apology, mind you, or retracted her statement.

Today, Dr Leaf published a blog on psychiatric medications … but again, not to apologise but to further justify why she is right, and nearly every other doctor and scientist in the world is not. Worse than that, she went so far as to accuse doctors of deliberately prescribing clearly dangerous drugs, which have no therapeutic effects, just because of some overcooked drug-company sponsored dinner and a few pens. More on that later.

Her post is a defiant deflection, a logically flawed and factually inaccurate criticism of modern psychiatry and psychopharmacology – not fueled by research, but largely based on the books of disgruntled fringe psychiatrists and researchers with an axe to grind.

Dr Leaf doesn’t discuss the actual science of the medications that she’s so against, but simply tries to create a smokescreen of distrust.

A good example of all that is wrong with this post is contained in the opening paragraph.

Today, it has become commonplace to say that people have chemical imbalances in their brain, most notably a disruption in the proper production of dopamine (for “diseases” like ADHD) and serotonin (for “diseases” like depression). These people, it is supposed, need drugs to “cure” these chemical imbalances, hence the terms “antipsychotics” or “antidepressants”.

The first thing to note is how Dr Leaf uses the term “cure”. No doctor ever uses the word “cure”, especially when talking about complex diseases. This is a pejorative term which is used to set up the implication that modern medicine is only interested in permanently fixing things. But it’s a straw man fallacy, a false premise that Dr Leaf then uses to cast the medical model as impotent and futile. Nice try, but no one in medicine ever promises cure, and no doctor in their right mind would ever be so narrow-minded as to suggest that drugs are the only treatment for every condition. This doesn’t mean that drugs are not useful, nor that the medical model is broken. As we’ll discuss soon, medications are extremely helpful for certain conditions, when used carefully, as are non-drug treatments like CBT.

Dr Leaf also puts inverted commas around the word “diseases” as if to suggest that ADHD and depression aren’t diseases, an act which smacks of petulance and willful ignorance, and is insulting to those who have or who have ever suffered from ADHD and depression.   Last week, Dr Leaf was happy to share that her eldest daughter suffered from bulimia and depression, but now she’s suggesting that depression isn’t really a disease. So what is it then? Malingering? Just personal weakness? Bad parenting?

It’s really surprising that someone claiming to be a cognitive neuroscientist would ignore strong scientific evidence.  For example, ADHD is associated with dopamine dysfunction as well as the dysfunction a number of other neurotransmitters [1-3]. And depression is associated with a decrease in the growth factor BDNF, (known as the neurotrophic hypothesis of depression) [4-6]. Schizophrenia, which Dr Leaf conveniently failed to mention, is clearly related to dopamine dysfunction in nerve cells of the pre-frontal cortex and the striatum, two parts of the brain that are incredibly important for how your brain processed incoming and outgoing signals [7-9].

So there is nothing to suppose here. There is ample evidence that psychiatric diseases are related to dysfunction within the brain, commonly with the function of neurotransmitters among other things. Call it whatever you like, the truth doesn’t change. “Chemical imbalance” is just an easy phrase for the general public to remember.

Dr Leaf then tries to suggest that psychiatric drugs don’t fix chemical imbalances but create them, citing the 1950’s observations of French researchers Deniker and Delay who noted that the first anti-psychotic, chlorpromazine, caused symptoms of Parkinson’s Disease. And indeed it did, but this wasn’t a new disease, just evidence that it worked.

Psychosis, a pathological state involving hallucinations and delusions, is because of an excess of the neurotransmitter called dopamine. Dopamine is the neurotransmitter that’s used by the nerve cells deep in the brain in a part called the basal ganglia, which acts like a central mail delivery centre for incoming and outgoing signals from other parts of the brain. The function of the nerves in one part of the basal ganglia are responsible for sending sensory signals to the frontal lobes of the brain. In another part, the signals are important for smooth movements of our muscles. Proper function depends on just the right amount of dopamine – too much and you get psychosis. Not enough and you get Parkinson’s disease symptoms.

All the French researchers were noting were the side-effects of too much medication blocking the action of dopamine in the basal ganglia – the psychosis had improved, but the blockade of dopamine was just too much in some patients, who had the opposite symptoms.

Again, Dr Leaf’s position is diametrically opposed to the published science [10, 11], and if anything, her claim contradicts her fundamental argument. After all, if chemical imbalances are myths, then how can chlorpromazine create a “new neurological syndrome” because of a chemical imbalance?

Dr Leaf then launches into a discussion on the history of the DSM and psychiatric medications. This is just the first in her ad hominem attacks on the medical profession –  playing the man, not the ball if you will. If she can discredit the doctors that prescribe the medication, then she indirectly discredits the medications.  This appears desperate and ultimately serves to weaken her case.

“It was just assumed that since these drugs affected brain chemistry in a certain way, the opposite reaction must be the result of the disease, notwithstanding the fact that this has never been adequately proven.”

The history of medicine is littered with cures being found without the disease being fully understood. Take Edward Jenner, for example, who is the founder of the modern technique of vaccination. He didn’t know why his smallpox vaccine worked, only that it did. Electron microscopes and a modern understanding of the immune system were centuries away, but Jenner saved billions of lives through his observation that prior vaccination with a small sample of cowpox virus would protect against smallpox [12].

When amphetamines, known to increase dopamine concentrations in the brain, caused psychotic symptoms and reserpine, a dopamine blocker, improved psychosis, it stood to reason that dopamine was a good candidate as a cause of psychosis and schizophrenia. Decades of research have gone on to further confirm and delineate the link [7]. Again, this is not “an overly simplistic explanation of chemical imbalances”. It is well proven, and rather complex.

Dr Leaf also makes the astounding accusation that psychiatrists inflicted suffering and caused “a public health disaster” by creating the DSM. The DSM, the ‘Diagnostic and Statistical Manual’ is an agreed-upon standard classification for psychiatric diagnoses. It is nothing more than a system of classification. It allows psychiatrists and researchers to speak a common language and attempt some coherence among their diagnoses.

Dr Leaf wrote, “… institutions like the American Psychiatric Association and the DSM would define what is normal, in turn telling us what it means to suffer and, essentially, what it means to be human. They medicalized misery, and today millions are suffering because of their actions, creating a public health disaster.”

That’s like saying that classifying the different types of cancer causes cancer. And that millions of people are suffering from cancer because doctors know to call it ‘cancer’. People have been suffering long before the DSM came along. The DSM doesn’t tell people they’re suffering, and it certainly doesn’t define what it is to be human. Such statements are disingenuous and melodramatic.

But wait, there’s more. “Today a psychiatrist can be praised for drugging a depressed person with mind-altering substances and, if these do not work, institutionalizing them and shocking their brain with ECT (electroconvulsive therapy). It is even an acceptable and commonplace practice to imprison mentally ill persons, drug them and lock them in solitary confinement, compelling them to live their days marinating in their own excrement.”

Dr Leaf is again playing to the fears of the public who have watched too many movies and only think of ‘One Flew Over the Cuckoo’s Nest’, ‘Shutter Island’ or scenes from ’12 Monkeys’. There are more oversight boards and lawyers than there are psychiatric patients, and the only people who are institutionalised are those who are clearly a danger to themselves or others. And while institutionalised, they are not subjected to random bouts of electrical shock as if some doctor is wandering around with a medical grade cattle prod, zapping people and laughing maniacally. Nor is anyone locked in solitary confinement and forced “to live their days marinating in their own excrement”.

The paranoid accusations continue some more. Dr Leaf accuses all psychiatrists of ignorance, and then accuses primary care physicians of negligence, by claiming that we prescribe medications that we do not understand because of the bribes and a pretty smile from a pharmaceutical rep.

Again, Dr Leaf contradicts her own argument:

Despite the recognition amongst many psychiatrists and medical health professionals that the chemical imbalance theory is not valid, drug companies like Eli Lilly still claim that ‘antipsychotic medicines are believed to work by balancing the chemical found naturally in the brain’.

Except that antipsychotic medications DO balance the naturally occurring chemical in the brain (dopamine) as we discussed earlier. What the … a drug company telling doctors how their drug works! How dare they tell the truth!

I find it disturbing that Dr Leaf would stoop so low as to insult the entire medical profession, especially every GP and family physician the world over.

Hey, I’m not above criticism. It’s important to have a good long look at ourselves from time to time, to review our practice, and make sure we’re treating our patients in the best possible way. The RACGP, the peak body of Australian GP’s, invited Prof Gøtzsche to present his opinions on anti-depressant medications so that GP’s could decide for themselves if they should adjust their prescribing.

But to suggest that primary care physicians are stupid, ignorant, incompetent and money hungry, that we would sell our soul for a drug company branded pen, is insulting. Though the irony of her statement, “we do not ask ourselves if these doctors really understand all the implications of using these substances. Not even the psychiatrists understand these drugs” is clearly lost on Dr Leaf.  It’s clear from the rest of her essay that Dr Leaf has no idea how these medications work or what benefits they have for those who suffer from mental ill-health.

There’s a lot more to discuss in response to Dr Leaf’s diatribe, but for the sake of brevity, I’ll try and discuss just a couple of other important themes.

Dr Leaf continues to try to make the medications sound useless and poisonous. She has several paragraphs on the placebo effect, making the false argument that the effect of the medications is just because someone tells you it will work. Of course, the placebo effect is part of the therapeutic effect, but that’s the same for all treatments, even Dr Leaf’s programs … “So, if the pastor or cell-group leader says that these programs are safe and will fix your toxic thinking, even though they get most of their information from the author, we believe wholeheartedly in what he or she may say and are more inclined to believe the program will work for us. These beliefs, which ignore actual scientific results, are buttressed by a flood of distorted and biased news reports, press releases and scientific journal articles on supposed toxic thoughts, and have transformed the theory into church dogma. So, obviously, if we experience negative side effects and do not feel the program is working, it must be something wrong with us, not the program.” Is that a fair statement?

Dr Leaf that plays the fear card again by listing all of the potential side effects from psychiatric medications. Dr Leaf is right in saying that psychiatric medications have serious proven long term side effects, and we should be careful.

For instance, if you knew that thrombocytopenia, anaphylaxis, cutaneous hypersensitivity reactions including skin rashes, angioedema and Stevens Johnson syndrome, bronchospasm and hepatic dysfunction were the potential side effects for a medication, would you take it? Most people wouldn’t.   Reading the list makes that drug sound really dangerous, and is it any wonder that we should be up in arms about such a dangerous drug … except that this list of side effects isn’t a psychiatric drug at all, and is actually the side effect profile of paracetamol (acetaminophen in the US). People take paracetamol all the time without even thinking about it.

Saying that we shouldn’t take medications because of potential side effects is a scarecrow argument, a scary sounding straw man fallacy. All drugs have serious proven long term side effects. Licencing and prescribing a medication depends on the overall balance of the good and the harm that a medication does. And no one has ever hidden these side effects from the public as if there is a giant conspiracy from the doctors and the pharmaceutical companies. They’re right there in the product information (here is the product information for fluoxetine. See for yourself).

Whilst it’s true that these side effects do happen, we know that they happen infrequently, just like we know that people win lotteries infrequently. Even so, the medications are not just doled out like sweets at a candy store. You require a minimum of ten years of university level education to be able to prescribe them.

Patients ALWAYS have a right to ask questions about possible benefits and side effects, and in my practice, I tell my patients the pros and the cons before prescribing, and I give them the choice of whether they want them or not. No one is ever forced into taking them.

Finally, Dr Leaf makes a number of irrational statements and flawed arguments in her final page of ranting. Let me quickly go through some of the honourable mentions:

* “Most people recover from depression without antidepressants” – true, because most cases of depression are mild. That doesn’t mean to say that antidepressants shouldn’t be used for severe depression, just like most people recover from upper respiratory infections without antibiotics, but that doesn’t mean that we shouldn’t use antibiotics for severe tonsillitis or pneumonia.
* “Antidepressants are no better than placebos” – It’s a controversial topic right now. There are many pushing the barrow that SSRI medications are no better than a sugar pill. But Dr Leaf has conveniently ignored several Cochrane reviews (the best of medical evidence) that shows anti-depressants work for a variety of disorders [13-15], but that psychological therapy might not [16].
* Equating antidepressants and antipsychotics with illicit drugs, and claiming that “more people die from overdoses of psychiatric drugs than illicit drugs” – This is Reductio ad absurdum – the logical conclusion from this argument is that illicit drugs are safer than psychiatric drugs. And therefore we should not give people psychiatric drugs since we don’t give people the ‘safer’ illicit drugs. But that conclusion is absurd, and when you think about it, the whole thing is based on hidden false premises – people rarely die of illicit drug overdoses because they’re illegal and are hard to come by. And also, people who use illicit drugs are not usually suicidal, whereas those given psychiatric medications sometimes are suicidal, and sometimes use them to try and commit suicide. But modern psychiatric drugs are much less dangerous in overdose than their old counterparts.  It should also be noted here that more overdose suicide attempts are with paracetamol or ibuprofen than with psychiatric medications [19], but I don’t see paracetamol or ibuprofen being demonised.
* Psychiatric medications are part of a neo-liberal capitalist plot to keep the rich, richer and the poor, poorer – To me, this looks like Dr Leaf clutching at straws. Her statement, “By emphasizing that the problem lies within an individual’s biology, we are less inclined to look at their experiences and the social context of why they are feeling the way they feel. We look at the mythical chemical imbalance instead of economic exploitation, violence and inept political structures” is false.   Schizophrenia is often seriously discussed in terms of neurodevelopment and not just ‘chemical imbalances’ [17, 18]. So it’s just plain wrong to suggest that researchers don’t look at the “economic exploitation, violence and inept political structures”. Oh, and Dr Leaf suggests that foster children are abused because they’re all forced to take psychiatric medication, and implies that ADHD children are abused by being force-fed Ritalin because they “move a lot in class”. Again, these are emotional over-generalisations that have no basis in reality.

And this was only part one.  If Dr Leaf’s promised second part is anything like the first, we’re in for a real treat.

Dr Leaf seems lost.  She’s ignored solid published medical and scientific evidence in coming to an opinion based on the discontented rumblings of a few vocal but outspoken critics. In order to make her arguments, she has had to resort to borderline-slanderous ad hominem attacks on scientists and the medical profession, and purely emotional arguments based on fear and mistrust.

Though as if that wasn’t enough, by suggesting that psychiatric drugs cause changes in your brain, cause chemical imbalances, and cause that slew of negative side effects, Dr Leaf is admitting that it’s your brain that changes your thought life, which directly contradicts her most recent teachings. After all, if thought was the dominant force in your neurology and your mind controlled your brain, then the medications would have no effect since they’re physical and aren’t connected to our mind, so there would be no need for Dr Leaf to worry us about these medications.

So which is it? Because if the brain controls our mind, then her best-seller needs to be pulped and refunds offered to the hundred of thousands of people who bought it. But on the other hand, if the mind really does control the brain, then you’re wrong to tell people that these drugs will change your thoughts.

Dr Leaf has painted herself into a corner and there’s still part two to come.


[1]        Prince J. Catecholamine dysfunction in attention-deficit/hyperactivity disorder: an update. J Clin Psychopharmacol 2008 Jun;28(3 Suppl 2):S39-45.
[2]        Del Campo N, Chamberlain SR, Sahakian BJ, Robbins TW. The roles of dopamine and noradrenaline in the pathophysiology and treatment of attention-deficit/hyperactivity disorder. Biological psychiatry 2011 Jun 15;69(12):e145-57.
[3]        Cortese S. The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): what every clinician should know. European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2012 Sep;16(5):422-33.
[4]        Haase J, Brown E. Integrating the monoamine, neurotrophin and cytokine hypotheses of depression–a central role for the serotonin transporter? Pharmacol Ther 2015 Mar;147:1-11.
[5]        Bus BA, Molendijk ML, Tendolkar I, et al. Chronic depression is associated with a pronounced decrease in serum brain-derived neurotrophic factor over time. Molecular psychiatry 2015 May;20(5):602-8.
[6]        Sousa CN, Meneses LN, Vasconcelos GS, et al. Reversal of corticosterone-induced BDNF alterations by the natural antioxidant alpha-lipoic acid alone and combined with desvenlafaxine: Emphasis on the neurotrophic hypothesis of depression. Psychiatry research 2015 Sep 1.
[7]        Howes OD, Fusar-Poli P, Bloomfield M, Selvaraj S, McGuire P. From the prodrome to chronic schizophrenia: the neurobiology underlying psychotic symptoms and cognitive impairments. Curr Pharm Des 2012;18(4):459-65.
[8]        Williams GV, Castner SA. Under the curve: critical issues for elucidating D1 receptor function in working memory. Neuroscience 2006 Apr 28;139(1):263-76.
[9]        Der-Avakian A, Markou A. The neurobiology of anhedonia and other reward-related deficits. Trends Neurosci 2012 Jan;35(1):68-77.
[10]      Leucht S, Tardy M, Komossa K, et al. Antipsychotic drugs versus placebo for relapse prevention in schizophrenia: a systematic review and meta-analysis. Lancet 2012 Jun 2;379(9831):2063-71.
[11]      Torniainen M, Mittendorfer-Rutz E, Tanskanen A, et al. Antipsychotic treatment and mortality in schizophrenia. Schizophrenia bulletin 2015 May;41(3):656-63.
[12]      Riedel S. Edward Jenner and the history of smallpox and vaccination. Proc (Bayl Univ Med Cent) 2005 Jan;18(1):21-5.
[13]      Arroll B, Elley CR, Fishman T, et al. Antidepressants versus placebo for depression in primary care. The Cochrane database of systematic reviews 2009(3):CD007954.
[14]      Soomro GM, Altman D, Rajagopal S, Oakley-Browne M. Selective serotonin re-uptake inhibitors (SSRIs) versus placebo for obsessive compulsive disorder (OCD). The Cochrane database of systematic reviews 2008(1):CD001765.
[15]      Kapczinski F, Lima MS, Souza JS, Schmitt R. Antidepressants for generalized anxiety disorder. The Cochrane database of systematic reviews 2003(2):CD003592.
[16]      Jakobsen JC, Lindschou Hansen J, Storebo OJ, Simonsen E, Gluud C. The effects of cognitive therapy versus ‘treatment as usual’ in patients with major depressive disorder. PloS one 2011;6(8):e22890.
[17]      van Os J, Linscott RJ, Myin-Germeys I, Delespaul P, Krabbendam L. A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder. Psychological medicine 2009 Feb;39(2):179-95.
[18]      Howes OD, Murray RM. Schizophrenia: an integrated sociodevelopmental-cognitive model. Lancet 2014 May 10;383(9929):1677-87.
[19]     Prescott K, Stratton R, Freyer A, Hall I, Le Jeune I. Detailed analyses of self-poisoning episodes presenting to a large regional teaching hospital in the UK. Br J Clin Pharmacol 2009 Aug;68(2):260-8.


  1. Do not abruptly stop any medications that you are taking. Talk to your licenced physician first. They’re not all money-hungry, imbecilic drug-company bitches. Most of them actually know what they’re talking about.
  2. For the record, I declare that I have no connection with any pharmaceutical company. I do not accept gratuities of any form from any sales representative. I don’t eat their food, I don’t take their pens, and I don’t listen to their sales pitches

The significance of thoughts

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A few days ago, I posted a rebuttal to one of Dr Leaf’s favourite memes, “Thoughts are real and occupy mental real estate.”

In short, I wrote that thoughts are real, but the issue hasn’t ever been whether thoughts are real, but what thoughts really are. The conclusion was that thoughts are just a projection, a function of the brain. They are not independent of the brain and they do not control the brain.

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. Dr Leaf tried to refine her meme today, saying:

“Your thoughts produce proteins, which form real structures that change the landscape of your brain.”

So, is that true? Do thoughts produce proteins which change the structure of the brain? To answer that, we need to have a look at some basic neurobiology.

The brain is made of nerve cells. Nerve cells have three unique structures that help them do their job. First are dendrites, which are spiny branches that protrude from the main cell body, which receive the signals from other nerve cells. Leading away from the cell body is a long thin tube called an axon which helps carry electrical signal from the dendrites, down to the some tentacle-like processes that end in little pods. These pods, called the terminal buttons of the axon, and then convey the electrical signal to another nerve cell by directing a burst of chemicals towards the dendrites of the next nerve cell in the chain.

In order for the signal to be successfully passed from the first nerve cell to the second, it must successfully traverse a small space called the synapse.

Despite being very close to each other, no nerve cell touches another. Instead, the spray of chemicals that’s released from the terminal button of the axon floats across a space of about 20-40nM (a nanometre is one billionth of a metre).

Combining nerve cells and synapses together creates a nerve pathway, where the input signal is received by specialised nerve endings and is transmitted down the nerve cell across a synapse to the next nerve cell, across the next synapse to the next nerve cell, and on and on until the signal has reached the destination for the output of that signal.

And that’s it. The entire nervous system is just a combination of nerve cells and the synapses between them.

What gives the nervous system and brain the near-infinite flexibility, and air of mystery, is that there are eighty-six billion nerve cells in the average adult (male) brain. Each nerve cell has hundreds to thousands of synapses. It’s estimated that there are about 0.15 quadrillion (that’s 150,000,000,000,000) synapses throughout the average brain [1]. Each of these cells and synapses connect in multiple directions and levels, and transmit signals through the sum of the exciting or inhibiting influences they receive from, and pass on to, other nerve cells.

The brain is a highly plastic organ. When biologists talk about plasticity, they aren’t talking about the chemical plastic that we make everything out of, like plastic cups or bottles, but the ability for the cells, tissues or organs to change or adapt. And the brain does this all of the time. Every stimulus changes one or more of the billions of branches and synapses that the brain has. Branches can be pruned back, or new ones grown. Existing branches can be strengthened or weakened. Each change to the branches of the nerve cells helps the brain to adapt to the ever-changing internal and external stream of signals that the brain is required to process.

So returning to Dr Leaf’s statement: The key part of the meme is, “Your thoughts produce proteins”. This is where Dr Leaf’s statement is wrong. The error is deceptively subtle, but it’s still wrong. When changes are required, new branches are formed, which do indeed require new proteins. But most brain function, including our thoughts, is simply electrical current running along the pathways already formed by the branches of our nerve cells.

Even then, our stream of conscious thought is only a tiny fragment of the billions of nerve impulses our brains produce each and every second of our lives. As I described in my previous post, thought is not dominant. Our thoughts do not control our brains, it’s our brains that control our thoughts. Thoughts are real, but they’re real like an image on a screen is real, but isn’t the real thing.

Thoughts are only significant when they are considered for what they truly are. Our stream of consciousness is simply a selective place of refinement for highly salient parts of our non-conscious information that need further processing before further action is taken with that information. They are like the dials on your dashboard, which give selective important information about the car but they don’t control the car. Thoughts do not control our brains growth, or alter our brains architecture.

Dr Leaf should have said something along the lines of, “The landscape of the brain is created by real structures called neurons and synapses, which have many functions including our thoughts.”

As it is, Dr Leaf’s meme creates a false impression that our thoughts are the critical factor in determining our brains structure and function, when the reality is the exact opposite.


[1]        Sukel K. The Synapse – A Primer. 2013 [cited 2013 28/06/2013]; Available from: http://www.dana.org/media/detail.aspx?id=31294

Dr Caroline Leaf – Thoughts are real. So what?

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Today’s meme from Dr Leaf is one of her favourite, often repeated phrases:

“Thoughts are real and occupy mental real estate.”

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. Her entire preaching empire rests on her assumption that our thinking is the driving force of not just our mental health but also our physical health, and even physical matter!

No one’s denying that thoughts are real. The key issue is not whether thoughts are real, but what thoughts really are.

Professor Bernard J. Baars is an Affiliate Fellow at The Neurosciences Institute in La Jolla, California. He is a real cognitive neuroscientist. In the late 1980’s, Professor Baars built on Baddeley’s model of working memory by proposed the Global Workspace theory [1]. Together with Professor Stan Franklin, also a real cognitive neuroscientist (and a mathematician and computer scientist) at the University of Memphis, they took the Global Workspace theory further with the Intelligent Distribution Agent model [2]. Central to this model is the “Cognitive Cycle”, a nine-step description of the underlying process from perception through to action. In the model, implicit neural information processing is considered to be a continuing stream of cognitive cycles, overlapping so they act in parallel. The conscious broadcast of our thought stream is limited to a single cognitive cycle at any given instant, so while these thought cycles run in in parallel, our awareness of them is in the serial, sometimes disparate, streams of words or pictures in our minds. Baars and Franklin suggests that about ten cycles could be running per second, and since working-memory tasks occur on the order of seconds, several cognitive cycles may be needed for any given working memory task, especially if it has conscious components such as mental rehearsal [2].

In recent years, the Global Workspace/Intelligent Distribution Agent hypothesis has been updated to help facilitate the quest to create different forms of artificial intelligence. The LIDA (“Learning Intelligent Distribution Agent”) model incorporates the Global Workspace theory with the concepts of memory formation to create a single, broad, systems-level model of the mind.

Franklin et al summarise the process, “During each cognitive cycle the LIDA agent first makes sense of its current situation as best as it can by updating its representation of its current situation, both external and internal. By a competitive process, as specified by Global Workspace Theory, it then decides what portion of the represented situation is the most salient, the most in need of attention. Broadcasting this portion, the current contents of consciousness, enables the agent to chose an appropriate action and execute it, completing the cycle.” [3]

Information within the cognitive cycle is broadcast to our consciousness in order to recruit a wider area of the brain to enhance the processing of that information [2, 4]. It’s the broadcasting of this portion of the information flow that renders it “conscious”.

So thought is nothing more than a broadcast of one part of a deeper flow of information. In the same way that a projection on a movie screen is a real series of images of a historical or fictional event, but not the actual event, so thoughts are a real but are just a projection of the deeper information stream within the brain.

This is very important, as it means that thought is not an instigator or a controlling force. It’s not a case of, “I think, therefore, I am”, but, “I am, therefore, I think.

So Dr Leaf is right, thoughts are real. So what? Thoughts are just a projection, a function of the brain. They are not independent of the brain and they do not control the brain. And they definitely don’t control physical matter.

In posting things like todays meme, Dr Leaf is proving just how far her assumptions are from the work of real cognitive neuroscientists, while misdirecting her audience, duping them into believing that her tenuous speculation is scientific fact.


[1]        Baars BJ. A cognitive theory of consciousness. Cambridge England ; New York: Cambridge University Press, 1988.
[2]        Baars BJ, Franklin S. How conscious experience and working memory interact. Trends in cognitive sciences 2003 Apr;7(4):166-72.
[3]        Franklin S, Strain S, McCall R, Baars B. Conceptual Commitments of the LIDA Model of Cognition. Journal of Artificial General Intelligence 2013;4(2):1-22.
[4]        Baars BJ. Global workspace theory of consciousness: toward a cognitive neuroscience of human experience. Progress in brain research 2005;150:45-53.

Dr Caroline Leaf and the Mental Monopoly Myth (Mark II)


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In my last post, I asked the question, “What’s more important to a person’s health and well being?” and I showed that Dr Caroline Leaf proposition that the mind dominates ones mental health and well-being is patently false.

Not to be outdone, Dr Leaf countered today with a tweak to her initial proposition: “Mind-action is actually THE predominant element in mental well-being.”

Dr Caroline Leaf is a communication pathologist and self-titled cognitive neuroscientist. She’s also started calling herself an expert in mental health, despite never having trained in medicine or psychology, or working in counselling.

Dr Leaf may have tightened up her wording from her previous statement, but her claim that mind-action is the predominant element in mental well-being is still wrong, because her fundamental assumption is wrong.

What fundamental assumption? That the brain doesn’t control the mind, but the mind controls the brain.

As I discussed in the last post, this idea of the mental monopoly dominates every one of Dr Leaf’s works, and most of her social media memes. Take her most recent meme for example, published just today, “The brain is not a chemical stew that is missing a key spice! The brain is hugely complicated and complex and is controlled by the even more hugely complex and eternal mind!”

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The premise that the mind controls the brain is wrong. Completely and utterly wrong. It is precisely the opposite of what science tells us. The mind is a function of the brain, just like breathing is a function of the lungs. No lungs, no breath. No brain, no mind. (see my posts here, here and here, and others for further discussion)


It’s been said, “Consistency: It’s only a virtue if you’re not a screwup.” Perhaps that’s a little harsh, but it does illustrate the point that just because you say something often enough, doesn’t make it true. So no matter how many times Dr Leaf repeats herself, the fact that the brain controls the mind isn’t going to change.

Even without appealing to the plethora of scientific information out there, Dr Leaf’s claim that mind-action dominates mental well-being is wrong, since mind-action is simply brain-action, which in turn, is influenced by the complex interplay of our genes, our physical health, our uncontrollable external environment, our social networks and our spirituality. Our mental well-being is no different to our general well-being in this regard. It is still part of the complex interplay that is represented by the biopsychosocial (and spiritual) model.

It’s time for Dr Leaf to update her teaching, and abandon her unscientific presuppositions and philosophies.

Dr Caroline Leaf – Better graphics, same content

Screen Shot 2015-09-04 at 2.08.15 pm

In the world of marketing, visual media is king. Humans are sight based creatures. About thirty percent of our brains cortex is dedicated to vision , compared to 8 percent for touch and 2 percent for hearing http://channel.nationalgeographic.com/brain-games/articles/brain-games-watch-this-perception-facts/)

It’s no wonder then that sites like Pinterest and Instagram have so rapidly become such dominant sites on the social media landscape. And why billions of dollars are invested in visual advertising on TV and billboards.

Dr Caroline Leaf is a communication pathologist and self titled cognitive neuroscientist. In the last few weeks, she’s gone for a new look for her Instagram and Facebook posts – gone are the simple lines, plain text and stand alone logo. Her posts have gone glam, with backgrounds of her photo treated with coloured layering and shading, overlaid with Dr Leafs favourite text. Sometimes the text is pretty easy to read. Other times it looks like a 4th grade class got to take turns picking the font and text size for each different word. But hey, it’s edgy, it’s happening, it’s so hot right now.

It’s a real shame that she only chose to update the look and not the actual content of her social media memes. Take today’s offering as an example: “The mind processes. The brain reflects this processing.” (The unsaid conclusion being that, “The mind controls the brain.”)

I’ve written about this meme a few times (here, here, here and here, as a small sample). But let’s relook at it again, since Dr Leaf is unwilling to reconsider the statements lack of validity.

Does the mind really control the brain, or does the brain control the mind? Well, if the mind was separate from the brain and controlled the brain, then the mind would be able to function independently of the brain. And also, if the mind was separate to the brain, then changes to the brain would not influence the function of the mind.

It’s difficult to show that a person has a mind without a brain. You can’t really remove someone’s brain and then put it back again, so not many people are keen to volunteer for that study. But anecdotally, have you ever heard of a person who has woken from a coma having spend all that time in deep thought?

What IS much easier to study, and has been proven over the course of centuries, is the change to our cognitive function when our brain is changed, physically or functionally.

The mind changes when the function of the brain is changed by medications.
The mind changes when the function of the brain is changed by illicit drugs.
The mind changes when the function of the brain is changed by electrical stimulation.
The mind changes then the structure of the brain is changed by tumours or injuries.

In 1848, a man named Phineas Gage was packing gunpowder in some rock when an accidental detonation blasted a foot-long iron rod through the left face and forehead, severely damaging the left frontal lobe of his brain. History records that his personality changed from polite, well mannered, and well spoken to fitful, irreverent, impatient of restraint or advice, obstinate and capricious [1].

Whilst Phineas Gage was is most famous, other brain injuries can also change the way in which someone thinks. For example, lesions of the parietal lobe of the brain changes the way people see their own bodies. Baars writes, “Patients suffering from right parietal neglect can have disturbing alien experiences of their own bodies, especially of the left arm and leg. Such patients sometimes believe that their left leg belongs to someone else (often a relative), and can desperately try to throw it out of bed. Thus, parietal regions seem to shape contextually both the experience of the visual world and of one’s own body.” [2]

Some might argue that the mechanism of injury might be the variable that could change someone’s personality. After all, if an iron rod was blasted through my skull, I might be a little antsy too. But other structural change to the brain, not associated with a sudden traumatic event, can also result in personality changes – it’s well recognised that personality changes can be the first presenting symptom of brain tumours, for example.

Though the brain doesn’t have to be horribly distorted for the mind to change. In the last couple of decades, a tool has been developed called TMS – short for transcranial magnetic stimulation. A magnetic pulse is delivered over a part of the skull, passing through the bone to reach the brain, causing changes to the electrical current running through the nerve cells. Stimulation of different intensities can either turn off the nerve cells or excite them. TMS has become a great tool for studying cognitive neuroscience because it directly changes the function of the brain in a well localised and temporary manner. It’s also easy for scientists to blind the subjects to whether they’re receiving the treatment or a sham treatment, so the results are reliable. Research shows that when the frontal lobes of the brain are changed by the electrical signals, their executive function also changes [3].

Changes to the function of the brain are known to change the function of the mind and have been known to do so for centuries. From religious hallucinogens to Woodstock hippies, drugs of various forms have been used to alter mood, thought, and perceptions of reality. But there’s a drug that’s much more common, that’s known for its ability to alter our brains thinking ability the world over, and even Dr Leaf enjoys it.

Like most people, my morning doesn’t really start until after my first cup of coffee. Sure, I’m functional, but barely. Fifteen minutes after the first short black is in my system, I find that I’m much more alert and my thinking is clearer.

What’s changed? Is it my mind changing the function of my brain, or is it the coffee, specifically the caffeine in it, that’s changing my brain which is in turn is making my mind clearer and sharper? I think the answer is obvious. Caffeine is the most commonly used recreational drug in the history of mankind, and every cup of java (real coffee that is, not the travesty that is decaf) is more proof against Dr Leaf’s dogmatic misrepresentation of basic science.

So, if the mind is changed by alterations to the structure and/or function of our physical brain, it follows that our mind must be a function of our brain. Therefore, the mind does not process, while the brain simply hangs on for the ride. Rather, the brain processes, and our mind reflects this processing.

Dr Leaf can tart up her memes all she likes, but until she changes the content of her memes to match some actual science, it’s all just smoke and mirrors. The truth doesn’t need visual pimping. It is simply the truth.


[1]        Fumagalli M, Priori A. Functional and clinical neuroanatomy of morality. Brain : a journal of neurology 2012 Jul;135(Pt 7):2006-21.
[2]        Baars BJ. Global workspace theory of consciousness: toward a cognitive neuroscience of human experience. Progress in brain research 2005;150:45-53.
[3]        Guse B, Falkai P, Wobrock T. Cognitive effects of high-frequency repetitive transcranial magnetic stimulation: a systematic review. J Neural Transm 2010 Jan;117(1):105-22.

“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 – Still Contradicted by the Latest Evidence, Scripture and Herself

Leaf Cognitive Neuroscientist

Dr Caroline Leaf is a communication pathologist, world renowned author, public speaker, and self-titled cognitive neuroscientist. Her influence continues to grow. She is regularly invited to speak at some of the world’s largest churches. She spoke at her first TEDx conference in February, and she’s about to host her own conference for the second time. She has more than 120,000 Facebook followers, with many more on Twitter and other social media platforms. And she continues to top the sales charts of Christian best sellers.

She is a self-marketing machine.

But there are cracks appearing. More and more, people are realizing that beneath the facade of her numerous Instagram posts, happy snaps, and the allure of popular success, Dr Leafs teachings on science and the Bible don’t match up with actual science and good theology. While many in the church adorn themselves with her teaching, a growing minority are starting to realise that the Emperor has no clothes.

Almost two years ago to the day, I sat in the congregation of Kings Christian Church on the Gold Coast, and heard Dr Leaf speak live for the first time. What I heard troubled me, and I blogged about my concerns to open a dialogue on Dr Leaf and her teaching. Her husband, Mr Mac Leaf, dismissed my concerns out of hand, which only steeled me to take further action. Now, two years of intense research, dozens of posts and a book later, people are starting to take notice.

Not that Dr Leaf has changed her tune. Her fundamental teaching still relies on the idea that our thoughts control our physical and mental health, and toxic thinking causes disease because our thoughts change our DNA and the expression of our genes through epigenetics. And, if we ‘detox’ our thoughts, we will be restored to the health that God intended. Dr Leaf is also expanding her ministry to the subject of mental health and she plans to release a book on food in early 2016.

Dr Leaf can spruik whatever she likes, but her claims of expertise and her scientific and scriptural legitimacy are crumbling.

This post is a little longer than usual, but I’ve divided it up for easier reading:

  1. Dr Leaf is contradicted by her own qualifications
  2. Dr Leaf is contradicted by science
  3. Dr Leaf is contradicted by scripture
  4. Dr Leaf is contradicted by Dr Leaf

1. Dr Leaf is contradicted by her own qualifications

In her books, on TV, at churches, and in promotional material, Dr Leaf describes herself as a ‘cognitive neuroscientist’.

However, Dr Leaf does not have formal qualifications in neuroscience, has not worked at a university as a neuroscientist, has not worked in any neuroscience research labs, nor has she published any papers in neuroscience journals.

Actually, Dr Leaf is trained as a communication pathologist. A communication pathologist is an allied health professional which seems to be unique to South Africa where Dr Leaf trained. It’s a synthesis of audiology and speech pathology. It qualified her to work as a therapist, which Dr Leaf did for children with traumatic brain injuries. Dr Leaf also researched a narrow band of educational psychology as part of her PhD, and she also worked in a number of schools and for educational boards in South Africa. Dr Leaf hasn’t performed any university based research since her PhD was published in 1997.

In contrast, true cognitive neuroscientists actively carry out research into the biological basis of thoughts and behaviours – either mapping behaviours to certain brain regions using electrical currents from the brain, or with functional brain imaging like fMRI, or stimulating or suppressing the activity of a region of the brain and seeing how a person responds.

Simply having some training in neuroanatomy and psychology doesn’t make you a cognitive neuroscientist. Completing a PhD that involved a model for learning doesn’t make you a cognitive neuroscientist. Reading a lot of books on neuroscience doesn’t make you a neuroscientist either, just like reading the Bible doesn’t automatically make you a Pastor.

So no matter how much Dr Leaf may try to convince us that she’s an expert cognitive neuroscientist, truth be told, she is not.

Of more concern is that Dr Leaf is also trying to position herself as an expert in the fields of mental health and nutrition. But if she can’t get her facts right in an area in which she’s had some training, then it’s unlikely Dr Leaf’s teaching will be reliable in areas that she’s had no formal training or experience whatsoever.

I might add, Dr Leaf’s insistence that she’s a cognitive neuroscientist and an expert on mental health and nutrition is also quite insulting for real psychologists, neuroscientists and nutritionists whose opinions are ignored in favour of a self-titled expert whose only ‘authority’ comes by popular demand, not training or experience.

2. Dr Leaf is contradicted by science

There are so many examples of Dr Leaf being directly contradicted by the science that she claims expertise in that I don’t have room in this blog to outline them all. What I can do in this limited space is to outline Dr Leaf’s most egregious and ironic fallacies as a taster.

The 98 percent

One of Dr Leaf’s most fundamental assertions is that “75 to 98 percent of mental and physical illness comes from ones thought life” [1]. She uses this little factoid all the time to justify her belief in the power of thoughts.

However, her statement is completely wrong. When considered in the historical and global context [2], most of human illness is related to preventable diseases that are so rare in the modern western world because of generations of high quality public health and medical care.

For example, Hunter et al state that, “diarrhoeal disease is the second most common contributor to the disease burden in developing countries (as measured by disability-adjusted life years (DALYs)), and poor-quality drinking water is an important risk factor for diarrhoea.” [3]

De Cock et al write, “Recent estimates of the global incidence of disease suggest that communicable diseases account for approximately 19% of global deaths” and that “2.5 million deaths of children annually (are) from vaccine-preventable diseases.” [4]

Routine screening with the much-maligned pap smear has decreased the death rate from cervical cancer in women by as much as 83% [5]. And having a competent midwife and obstetric support during childbirth can decrease the odds of dying in childbirth from 1 in 6 to less than 1 in 30,000 [6].

Midwives, vaccinations, pap smears, clean drinking water and internal plumbing have nothing to do with our individual thought life. We take all of this for granted in the first-world, so the impact of our thought life becomes artificially inflated. In reality, modern medicine and civil engineering, not our thought life, have everything to do with our good health..

Though what makes this meme such a good example of the weakness of Dr Leaf’s teaching is not just because it’s contradicted by actual science, but in trying to justify her conjecture, Dr Leaf has resorted to twisting, misquoting, and generally fudging information from her ‘sources’ in order to make them support her false conclusions.

For example, Dr Leaf quoted a source on genetics that was over thirty years old, from a time when genetic studies were still in the dark ages. She also misquotes her sources, significantly changing the meaning of the quotes in the process. One source didn’t even mention the figure she attributed to it. As if that’s not bad enough, Dr Leaf also cites biased sources, pseudoscientists, and other sources that directly contradict her assertion [7; Ch 10].

This pattern of relying on mistruths and factoids to paper over the gaping cracks in her irrational assertions is repeated throughout her teaching.

The heart is a mini-brain

Dr Leaf believes that the human heart acts as a mini-brain. She states that the heart has its own thought functions, is an electrophysiological regulator of every cell in the body, and is the source of the human conscience.

Such an assertion is ludicrous, and science proves it to be so – the “still small voice” comes from our brains [8-10], and everyday office-based medical tests prove that the electromagnetic signal from the heart is too small to have any meaningful influence on our body’s cells, let alone our thinking [7: Ch 11].

You control your DNA with your thoughts

Dr Leaf believes that our thinking can influence our DNA. She said this in her 2013 book [1: p35], and several times on her social media streams. The problem for Dr Leaf is that there is no credible scientific evidence that DNA is controlled by thoughts.

Her main evidence comes from a poster presentation at a 1993 psychotronics conference titled, “Local and nonlocal effects of coherent heart frequencies on conformational changes of DNA” [11]. She describes this paper as, “An ingenuous experiment set up by the HeartMath Foundation (which) determined that genuine positive emotion, as reflected by a measure called ‘heart rate variability’, directed with intentionality towards someone actually changed the way the double helix DNA strand coils and uncoils. And this goes for both positive and negative emotions and intentions.” [1: p111]

Actually, the experiment was based on faulty assumptions, and so full of flaws in the methodology and analysis, that it could show nothing at all [7: Ch 13]. All it could prove was that Dr Leaf was so desperate to grasp hold of anything that seemed to support her theory that she was willing to use a twenty-year-old study from a group of pseudoscientists that also believe in occult practices like ESP and telekinesis (http://psychotronics.org).

On and on, the same pattern continues. She claims that our thoughts are powerful enough to control our DNA and our brain, except that the opposite is true – it’s our DNA code, with some influence from our environment, that creates our pattern of neurons responsible for our stream of thoughts. She teaches that thoughts cause stress, when again, the evidence is the opposite – psychological stress starts as a subconscious process which changes our stream of thoughts. Dr Leaf teaches that in order to improve our mental and physical health, we need to fight any ‘negative’ or ‘toxic’ thoughts, when studies show that cognitive therapy isn’t effective when compared to behavioural activation. (This is explained in more detail, and with the appropriate references, in my book [7]).

Dr Leaf even goes so far as to say that our thoughts can control physical matter! [1: p33,38]

Over and over again, Dr Leaf’s teaching conflicts with modern science. That Dr Leaf also regularly misquotes her sources and relies on unpublished opinion from pseudoscientists and new-age practitioners also brings her reputation as an expert scientist into disrepute.

3. Dr Leaf is contradicted by scripture

In her books and on social media, Dr Leaf often quotes scripture in an attempt to reinforce her reputation as some form of Biblical expert. Everything’s fine when she simply quotes scripture, but problems arise when she tries to interpret it. Like her use of science, Dr Leaf often misquotes or paraphrases scripture, or uses it out of context, in order to try and Biblically justify her tenuous hypotheses.

2 Timothy 1:7

One of Dr Leaf’s favourites is 2 Timothy 1:7: “For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.” Dr Leaf interprets the phrases of “spirit of fear” and “a sound mind” as “anxiety” and “mental wholeness” respectively. For example, on the 12th of May 2014, she posted to her social media feeds, “Your mind is all-powerful. Your brain simply captures what your mind dictates. 2 Timothy 1:7” And in her book “Switch on your brain” [1], she said on page 33, “For now, rest in the assurance that what God has empowered you to do with your mind is more powerful and effective than any medication, any threat, any sickness, or any neurological challenge. The scripture is clear on this: You do not have a spirit of fear but of love, power and a sound mind (2 Tim 1:7).”

Simply checking the verse in its full context, and in a different translation, shows it in a completely different light to the way Dr Leaf promotes it. From the NIV, “I am reminded of your sincere faith, which first lived in your grandmother Lois and in your mother Eunice and, I am persuaded, now lives in you also. For this reason I remind you to fan into flame the gift of God, which is in you through the laying on of my hands. For the Spirit God gave us does not make us timid, but gives us power, love and self-discipline. So do not be ashamed of the testimony about our Lord or of me his prisoner. Rather, join with me in suffering for the gospel, by the power of God.” (2 Timothy 1:5-8)

The Greek word for “fear” in this scripture refers to “timidity, fearfulness, cowardice”, not to anxiety or terror. The Greek word that was translated “of a sound mind” refers to “self-control, moderation”, not to mental wholeness. So Paul is teaching Timothy that God doesn’t make him timid, but full of power, love and self-control. Paul is simply saying that through the Holy Spirit, we have all the tools: power, love and the control to use them, so we don’t have to be afraid.

This scripture has nothing to do with our mental health. It certainly doesn’t say that our minds are “more powerful and effective than any medication, any threat, any sickness, or any neurological challenge”. Dr Leaf’s use of this scripture is misleading.

Proverbs 23:7

Another favourite of Dr Leaf’s is Proverbs 23:7, “For as he thinketh in his heart, so is he”.

She used this scripture a number of times on her social media feeds, including on the 4/2/2015, “‘The more you believe in your own ability to succeed, the more likely it is that you will. Shawn Achor’ – ‘For as he thinketh in his heart, so is he …’ Proverbs 23:7”, and the 29/5/2015, “Mind In Action: ‘Genes cannot turn themselves on or off. In more scientific terms, genes are not ‘self-emergent’. Something in the environment has to trigger gene activity.’ Dr Bruce Lipton’ – That ‘something’ is your thoughts! Read Proverbs 23:7”. Dr Leaf also used the same scripture to try and explain how the woman with the issue of blood managed to obtain her healing [1: p111].

What’s interesting is how Dr Leaf only ever uses the first half of this verse. The whole verse (in the King James Version) reads, “For as he thinketh in his heart, so is he: Eat and drink, saith he to thee; but his heart is not with thee.”

So what’s with the second half of the verse? What’s the eating and drinking half of the verse got to do with our thought life?

The explanation is that this verse has nothing to do with our thought life at all. Dr Leaf has simply been misquoting it for years, and no one checked to see if she’s right. According to the Pulpit commentary found on the Bible Hub website, “The verb here used is שָׁעַר (shaar), ‘to estimate … to calculate’, and the clause is best rendered, ‘For as one that calculates with himself, so is he’. The meaning is that this niggardly host watches every morsel which his guest eats, and grudges what he appears to offer so liberally … He professes to make you welcome, and with seeming cordiality invites you to partake of the food upon his table. But his heart is not with thee. He is not glad to see you enjoy yourself, and his pressing invitation is empty verbiage with no heart in it.” (http://goo.gl/nvSYUh)

Thus, the scripture does not prove that our thoughts define us as Dr Leaf would suggest. Dr Leaf’s use of this scripture is misleading.

James 1:21

Another example, on the 26 May 2014 on her social media feeds, Dr Leaf said, “James 1:21 How you react to events and circumstances of your life is based upon your perceptions” and then a week later, “James 1:21 Our thoughts and perceptions have a direct and overwhelmingly significant effect of the cells of our body” (4/6/2014).

Except that James 1:21 actually says, “Wherefore lay apart all filthiness and superfluity of naughtiness, and receive with meekness the engrafted word, which is able to save your souls”, and has absolutely nothing to do with our perceptions and our cellular biology.

The same pattern is repeated on social media and in her books. Dr Leaf finds scriptures where one version mentions words like “thinking” or “choice”, isolates them from their context and reinterprets them to suit her meaning, rather the actual meaning of the verse in the original language and the original context.

4. Dr Leaf is contradicted by Dr Leaf

Not only is Dr Leaf’s teaching contrary to science and scripture, but even her own teaching contradicts itself. Dr Leaf also makes claims about her research and achievements that aren’t backed up by her published papers.

To gift or not to gift …

In her 2009 book, “The gift in you” [12], Dr Leaf teaches about the gifts that we have, specifically, our gifts are something uniquely hardwired into our brain, something that we cannot change even if we wanted to, and that it’s our brain structure that gives rise to the way in which we think, the actions that we take, and the gifts we are given from God.

On page 47, Dr Leaf said,

The mind is what the brain does, and we see the uniqueness of each mind through our gifts. This, in itself is delightful and, intriguing because, as you work out your gift and find out who you are, you will be developing your soul and spirit.” (Emphasis added)

This quote in and of itself isn’t actually that significant until we compare it to a quote from the first chapter of Dr Leaf’s 2013 book, “Switch on your brain.” [1]

“The first argument proposes that thoughts come from your brain as though your brain is generating all aspects of your mental experience. People who hold this view are called materialists. They believe that it is the chemicals and neurons that create the mind and that relationships between your thoughts and what you do can just be ignored.
So essentially, their perspective is that the brain creates what you are doing and what you are thinking. The mind is what the brain does, they believe, and the ramifications are significant. Take for example, the treatment of depression. In this reductionist view, depression is a chemical imbalance problem of a machinelike brain; therefore, the treatment is to add in the missing chemicals.
This view is biblically and scientifically incorrect.” [1: p31-32] (Emphasis added)

So … our gifts are hardwired into our brain and can’t be changed because our mind is what our brain does OR our brain is what our mind does, so our gifts aren’t uniquely hardwired into our brain, and we should be able to change our gifting if we want to, based on our choices. Which is it? It can’t be both. Dr Leaf’s fundamental philosophies are mutually exclusive.

Now, we all make innocent mistakes. No one is perfectly congruent in everything they say. But this isn’t just getting some minor facts wrong. These statements form the foundation for Dr Leaf’s major works, and are in print in two best selling books, from which she has used to present countless sermons and seminars around the globe.

To summarise, Dr Leaf has directly called her own beliefs and teaching “biblically and scientifically incorrect”, and not noticed. The confusion and embarrassment are palpable.

But wait, there’s more.

(Not) Making a Difference

From the pulpit, in her books, and in her promotional material, Dr Leaf refers to her ground-breaking research – how her “Switch On Your Brain 5 Step Learning Process” and the Geodesic Information Processing model (which underpins her program), have helped thousands of children to increase their learning and improve their academic results.

For example, Dr Leaf claims that, “The Switch On Your Brain with the 5-Step Learning Process® was assessed in a group of charter schools in the Dallas [sic]. The results showed that the students’ thinking, understanding and knowledge improved across the board. It was concluded that The Switch On Your Brain with the 5-Step Learning Process® positively changed the way the students and teachers thought and approached learning.” (http://drleaf.com/about/dr-leafs-research/ – Original emphasis)

In her TEDx talk, Dr Leaf stated, “I wasn’t sure if this was going to have the same impact cause until this point I’d been working one on one. Well I’m happy to tell you that we had the same kind of results … The minute that the teachers actually started applying the techniques, we altered the trend significantly.” and,
“I stand up here saying this with conviction because I have seen this over and over and over in so many different circumstances … in this country I worked in Dallas for three years in charter schools, and we found the same thing happening.” [13]

Though there is the minor problem of her research results not demonstrating any actual change.

In Dr Leaf’s first case, Dr Leaf herself admitted that the demonstrated improvement of her single patient was just as likely to be related to spontaneous improvement, and not Dr Leaf’s intervention. In Dr Leaf’s PhD thesis, the students improved almost as much in the year without Dr Leafs intervention as they did with her program. In the Dallas charter schools study, Dr Leaf’s intervention either disadvantaged the students or showed no significant difference. In academic circles, Dr Leaf’s research hasn’t so much as generated a stale whimper [14].

So while Dr Leaf may claim that her research has changed the learning and lives of thousands of students all over the world, but her own published research disputes her claims.

The Emperor has no clothes, but no one wants to say anything

In Hans Christian Andersen’s legendary tale, the Emperor was conned by two swindlers into believing that “they were weavers, and they said they could weave the most magnificent fabrics imaginable. Not only were their colors and patterns uncommonly fine, but clothes made of this cloth had a wonderful way of becoming invisible to anyone who was unfit for his office, or who was unusually stupid.”

If you don’t know the story, you can read it here. In the end, the Emperor was duped so badly that he paraded in front of all his subjects au naturel, but “Nobody would confess that he couldn’t see anything, for that would prove him either unfit for his position, or a fool. No costume the Emperor had worn before was ever such a complete success.”

My analogy here is not to suggest that Dr Leaf is deliberately conning the church. Rather, our natural instinct is to suppress our own judgement, even when it’s right, in favour of everyone else’s. We assume information to be true because others in authority tell us it is. We assume that the Emperor must be wearing something because the trusted ministers and noblemen are holding his imaginary train high in the air.

Likewise, it’s very natural for Christians to believe that Dr Leaf’s teaching must be ok because our pastors and leaders vouch for it. Our pastors and leaders vouch for Dr Leaf’s teaching because it’s been endorsed by world-renowned Christian leaders like Kenneth Copeland and Joyce Meyer. And no one wants to say anything, because they don’t want to look sheepish (or be ostracised). Dr Leaf’s ministry may look like a complete success, but only until someone finally says, “But, the Emperor has no clothes …”

It’s time to call Dr Leaf’s ministry for what it is. In my humble opinion, I suggest that Dr Leaf’s ministry is not based on scientific acumen, but on popularity and reputation. And her reputation, in turn, is based on slick self-promotion and an availability cascade (a self-reinforcing process by which an idea gains plausibility through repetition).

Dr Leaf’s teachings are not supported by science, nor by scripture. Her own fundamental philosophies contradict each other. Her assertions about her title and the results of her work are in conflict with her own official data.

Our church leaders need to come clean about why they publicly endorse Dr Leaf’s ministry. I can justify why I think Dr Leaf should not be preaching from our pulpits – in this and many other blog posts, and in my 68,000 word rebuttal to Dr Leaf’s published works. Can Kenneth Copeland and Joyce Meyer, or churches such as Cottonwood Church or Hillsong Church, produce evidence where they performed due diligence on Dr Leaf’s scientific credibility before endorsing her ministry? I would be happy to publish any responses they may be willing to make, complete and unabridged.

If Dr Leaf is preaching at your church, politely ask your pastor to produce his or her evidence that Dr Leaf’s teaching is scientifically and scripturally sound. If your church leaders can’t show that Dr Leaf’s teachings are scientifically and scripturally accurate, then politely ask them why she’s been invited to preach from their pulpit or to sell her wares in your church? Feel free to share your experiences in the comments section.

Critics and sceptics love to use any opportunity they can to embarrass the church, but by parading our own naivety, we’re simply embarrassing ourselves.

It’s time we dressed ourselves in God’s glory, not our own ignorance and ignominy.


[1]        Leaf CM. Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. Grand Rapids, Michigan: Baker Books, 2013.
[2]        World Health Organization. GLOBAL HEALTH ESTIMATES SUMMARY TABLES: DALYs by cause, age and sex. In: GHE_DALY_Global_2000_2011.xls, editor. Geneva, Switzerland: World Health Organization,, 2013.
[3]        Hunter PR, MacDonald AM, Carter RC. Water supply and health. PLoS medicine 2010;7(11):e1000361.
[4]        De Cock KM, Simone PM, Davison V, Slutsker L. The new global health. Emerging infectious diseases 2013 Aug;19(8):1192-7.
[5]        Dickinson JA, Stankiewicz A, Popadiuk C, Pogany L, Onysko J, Miller AB. Reduced cervical cancer incidence and mortality in Canada: national data from 1932 to 2006. BMC public health 2012;12:992.
[6]        Ronsmans C, Graham WJ, Lancet Maternal Survival Series steering g. Maternal mortality: who, when, where, and why. Lancet 2006 Sep 30;368(9542):1189-200.
[7]        Pitt CE. Hold That Thought: Reappraising the work of Dr Caroline Leaf. 1st ed. Brisbane, Australia: Pitt Medical Trust, 2014.
[8]        Mendez MF. The neurobiology of moral behavior: review and neuropsychiatric implications. CNS spectrums 2009 Nov;14(11):608-20.
[9]        Zysset S, Huber O, Ferstl E, von Cramon DY. The anterior frontomedian cortex and evaluative judgment: an fMRI study. NeuroImage 2002 Apr;15(4):983-91.
[10]      Glascher J, Adolphs R, Damasio H, et al. Lesion mapping of cognitive control and value-based decision making in the prefrontal cortex. Proceedings of the National Academy of Sciences of the United States of America 2012 Sep 4;109(36):14681-6.
[11]      Rein G, McCraty R. Local and nonlocal effects of coherent heart frequencies on conformational changes of DNA. Proc Joint USPA/IAPR Psychotronics Conf, Milwaukee, WI; 1993; 1993.
[12]      Leaf CM. The gift in you – discover new life through gifts hidden in your mind. Texas, USA: Inprov, Inc, 2009.
[13]      Leaf CM. Ridiculous | TEDx Oaks Christian School | 4 Feb 2015. YouTube: TEDx, 2015;20:03.
[14]      Pitt CE, The TEDx Users Guide to Dr Caroline Leaf, cedwardpittcom; 2015   Mar 26, http://cedwardpitt.com/2015/03/26/the-tedx-users-guide-to-dr-caroline-leaf/