Anxiety Disorders, Panic, Phobias and Fear Part 2 Anxiety and the Stress Response: Not enough brakes and too much gas.
I’ve been studying stress and writing about it since the mid 1980’s. Back then every textbook on stress proclaimed that the stress response began in the Hypothalamus. All the renowned early experts on Stress from Walter B. Cannon to Hans Selye talked about, wrote about and studied the “HPA Axis”.
When the body is challenged by stress, the Hypothalamus releases CRH (corticotropin-releasing hormone) which causes the Pituitary gland (once upon a time incorrectly named the brain’s master gland) to release ACTH which when it arrives at the adrenal glands (sitting on top of the kidneys) causes them to release cortisol and adrenaline.
Then along came the Magnetic Resonance Imaging (MRI) device in the 1990’s. For the first time ever, scientists were able to look inside the brain without physically having to open it up. Along with that ability to bloodlessly peer inside the brain came a better understanding of exactly how the brain worked. And as a result, scientists were able to identify a little almond shaped area of the midbrain called the amygdala and see in real time exactly what it does. It’s the amygdala that is NOW thought to be the origin of the stress response.
Dan Goleman, told me that this spike in research in the 1990’s led to him writing his now world-famous series of best-selling books on Emotional and Social Intelligence. Goleman had a direct pipeline to this research through his Harvard buddy, Dr. Richard Davidson, (who liked to put meditating Tibetan Monks into an MRI at his lab at the University of Wisconsin). And it was in Dan’s writing both in the New York Times (he worked there as a science writer) and in his books where I first started to see the word amygdala. (Spell check annoyingly autocorrected it to amygdale for about 20 years between 1990 and 2010)
While it was Richard Davidson who provided us with a lot of information about how different parts of the brain worked in real time, the researcher who usually gets the credit for pointing out that the amygdala is the starting-off point for the stress response is a scientist named Joe LeDeux. So it was big news when about ten years ago, Dr. Joe changed his mind about the purpose of the amygdala. In his update to his original research, he opined that the amygdala was simply a “threat detector,” not necessarily the true source of our stress.
You see, the amygdala gets the information from the eyes and ears via a single neuron connection and immediately sounds an alarm. This can start the HPA axis in motion releasing CRH. (See above diagram.) The prefrontal cortex (PFC), now considered the executive center of the brain, gets the exact same information about a second later. If you were ever startled by a loud noise in the middle of the night, and then realized a moment later that it was probably the cat knocking something over, you have personally experienced this split second time gap between what the amygdala does: detect a threat and what the PFC does which is to determine if it REALLY is a threat.
I recently attended an all-day program on 6 forms of anxiety from OCD to PTSD. For various reasons, people who are diagnosed with an anxiety disorder, usually have an overly sensitive amygdala and a PFC that is not very skilled at down-regulating it. It’s what our presenter, Dr. Mark Schneider, described as having too much gas (in the amygdala) and not enough brakes (in the PFC). And it’s the research of Richard Davidson that has shown us how Tibetan Monks, who are the elite athletes of meditation, have PFCs that as Davidson described it are so much bigger than average, they’re“off the charts.” So, these monks have braking power to spare.
But Davidson has also put beginning meditators into his MRI device. And he has seen that even those who have practiced meditation for as little as 8 weeks, have the ability to control their emotions in ways that others, without a meditation practice don’t have. This research has been backed up by Harvard Professor, Dr. Sara Lazar, who like Davidson, puts meditators into an MRI and maps their brain. Her research also shows that there’s a shrinking in the size of the amygdala (less gas) and an increase in the size of the PFC (more brakes) for people who meditate as little as 20 minutes a day for 8 weeks. She told me in a podcast interview, that even if you think you are terrible at meditation, you will still get the benefit from having a regular practice. (You can watch this interview on our mental well-being web portal: My Stress Tools. Here’s where you can sign up for a 30-day free trial and listen to this podcast and many others.
Yoga, meditation and mindfulness which we will discuss later in this 10-part series are all ways of treating anxiety by changing the brain in the opposite direction of how stress changes the brain. In other words, these integrative therapies help to take the foot off the gas pedal and increase the ability of the PFC to apply the brakes.
In part 3 of this series, we’ll look at what habits and behaviors maintain and amplify anxiety in the brain, taking it from an occasional problem that EVERYONE experiences, to an ongoing disorder that affects less than 10% of the population. And in part 4-8 we’ll look at different anxiety disorders including Panic Disorder, Social Anxiety, Generalized Anxiety, and PTSD. In parts 9 and 10 we’ll look at a variety of treatments for anxiety. If you missed Part 1 Please click here.
James Porter
Author