Why Does Mindfulness-Based Cognitive Therapy Work?
Mindful meditation helps treat depression.
Posted Mar 10, 2015
Clinical psychologists have developed an impressive array of empirically supported treatments over the past several decades. While these new treatments have brought relief to many people, a stubborn scientific problem persists. I refer to the fact that psychologists don’t understand, and therefore can’t explain, how or why any of these treatments work. Mindfulness-based Cognitive Therapy (MBCT) is yet another new therapy that is effective but psychologists cannot explain how it works. The March 2015 issue of the Monitor on Psychology published by the American Psychological Association carried an article by Stacy Lu entitled “Mindfulness holds promise for treating depression”. This article states “While evidence suggests mindfulness works to help prevent depression relapse, researchers don’t yet know how” (p. 53).
Teo (2012) distinguished explanations from interpretations. Natural science explanations are based on principles whereas interpretations are not. While some interpretations are based on more and/or better data than others, they all remain just the personal opinion of the interpreter. Someone else may well provide a different interpretation. Scientific explanation goes beyond interpretation. Scientific principles are generalizations of established facts. While a particular airplane might fly, Bernoulli’s principle compels airplanes of a specific design to fly and thereby explains why they do. While a particular steel boat may float, Archimedes’ principle compels steel boats of a certain configuration to float and thereby explains why they do. This is why we prefer scientific explanations to interpretations.
All Cognitive Behavioral Therapies (CBTs) are based on the premise that how we think influences how we feel and behave. While this premise has guided the development of empirically supported treatments, it does not provide mechanism information that can explain how or why this should be the case. This explanatory problem is part of the larger explanatory problem I referred to in my previous blog entitled The Missing Link Between Psychology and Biology where I pointed out that the fields of psychobiology and biopsychology cannot explain how the mind influences the body and vice versa. I wrote Cognitive Neuroscience and Psychotherapy: Network Principles for a Unified Theory in order to provide some of this missing mechanism information. This includes a Bio<->Psychology Network (BPN) explanatory system based on four core and now nine corollary principles. We learned in my previous blog that the missing link between psychology and biology involves synapses, the junctions between neurons, and the experience-dependent plasticity mechanisms that produce learning and memory by modifying the extent to which synapses facilitate or inhibit activations moving from one neuron to others. The remainder of this blog provides an explanation of why Mindfulness-based Cognitive Therapy works.
Neuroplasticity and Priming
The brain is a network or neural networks. Hence, some form of network theory is required to explain how MBCT works. The Bio«Psychology Network explanatory system identifies core and corollary network principles that have been extensively supported by empirical research. The first core principle holds that the neural activations associated with our thoughts and feelings cascade across this network of neural networks. The second core principle holds that each processing pathway taken through this network activates experience-dependent plasticity mechanisms that biologically reinforce, strengthen, it. This results in memory formation and learning. The well-replicated psychological phenomenon of repetition priming is evidence that this explanation is correct. Repetition priming involves repeated stimulus presentations. These presentations prepare, biologically reinforce, processing pathways in predictable ways. For example, if you have someone say the word BOKE repeatedly and rapidly 20 or 30 times and then ask them “what we call the white part of the egg”, they will predictably say YOKE even though that is the yellow part of the egg. Repeatedly activating the letters OKE by repeatedly and rapidly saying the word BOKE primes saying the word YOKE because they share three letters in common. The person’s prior history of saying egg yoke also primes them to say YOKE. The key idea here is that brain neuroplasticity means that the brain changes in response to experience and those changes influence think, feel, and behave. These changes are rapid and dynamic which is why the above mentioned exercise works in less than a minute.
The “Define:Rumination” command returns the following definition: “The act of thinking about something in a sustained fashion”. Psychologists distinguish rumination from productive problem solving in that rumination features what is known as the depressive triad. That is, attributions concerning causes of events in our lives are: a) internal, b) global, and c) stable. Internal attributions are those that hold the person responsible for bad events even though they may have not had any control over what happened to them. We don’t completely control everything that happens to us except that the depressed mind thinks so. The term global means that these internal attributions are made for everything regardless of how silly such attributions are. They don’t appear to be silly to the depressed mind. Depressed people can hold themselves personally responsible for anything and everything. The term stable means that the depressed mind sees little to no hope for a better future. Suicide results from profound hopelessness.
The problem with rumination is that it primes, biologically reinforces, the brain to process thoughts in ways that are internal, global, and stable. Rumination recruits neuroplasticity mechanisms to biologically strengthen and elaborate neural networks to process attributions as internal, global, and stable. For example, it has been shown that more motor cortex is devoted to operating the violinist’s left hand than is devoted to operating their right hand. This is because the fingers of the left hand have more to do while playing the violin than the fingers of the right hand do. The brain changes how it allocates resources based upon need. Rumination reallocates brain resources in ways that can predispose one to become depressed, exacerbate an existing depression, and/or promote relapse back into depression.
Mindfulness meditation was once presented as something that monks and yoga masters took decades of dedicated training to learn to do. The mystery around meditation has gradually decreased to where Lu (2015) presented “The simplest definition of mindfulness is paying attention to one’s experience in the present moment” (p. 52, emphasis added). Placed in the context of neuroplasticity and priming we can see that mindfulness meditation works because it disrupts rumination. Focusing one’s attention on their experience in the present moment is incompatible with, precludes, cognitive triad processing, which explains its antidepressive properties.
Depressed people frequently mistake their rumination for problem solving which it is not because problem solving is positive and solution focused. Rumination is negative and disparaging of all proposed solutions. MBCT works because it diverts all cognitive processing back to present experience. This constant diversion precludes ruminative processing. An important component of mindfulness meditation is to let thoughts come and go as you return your attention to present experience. Tryon (2014) reported that “We are the editors, not the authors of our thoughts” (p. 176, bold emphasis in the original). While one cannot stop rumination from starting, they can refuse to participate and thereby biologically reinforce rumination by returning attention to present experience.
So how can not participating in rumination be helpful? Why would not participating in rumination change anything? Are the brain changes caused by rumination reversible? The short answer is yes. Not biologically reinforcing ruminative pathways enables the synapses involved in these processing pathways to moderate. The violin example of neuroplasticity mentioned above emphasized that the demands of practice caused the brain to allocate more motor cortex to manage the fingers of the left than right hand. This asymmetry will decrease and disappear if the violinist does not practice. This happens because neural networks consume a lot of energy and the brain takes down extensive unused circuits to save energy. The “use it or lose it” principle is operative here. Hence, not biologically reinforcing ruminative processing is the best way to take down the neural networks that mediate such thinking.
In sum, rumination activates and thereby develops extensive neural networks that process internal, global, and stable attributions that foster depression and that these neural networks will dissipate if they are not biologically reinforced through continued use. MBCT provides a respite from rumination and thereby enables the ruminative networks to be taken down. This results in healthier cognition and emotion. The following TED video by Dr. Sara Lazar provides more information regarding how meditation modifies the brain.
Lu, S. (2015). Mindfulness holds promise for treating depression: New research suggests that practicing mindfulness may help prevent a relapse. Monitor on Psychology, 46, (3), 50-54.
Teo, T. (2012). Psychology is still a problematic science and the public knows it. American Psychologist, 67 (9), 807-808.
Tryon, W. W. (2014). Cognitive neuroscience and psychotherapy: Network Principles for a Unified Theory. New York: Academic Press. http://store.elsevier.com/9780124200715