Kathleen Kawamura, PhD Clinical Psychologist
Kathleen Kawamura, PhDClinical Psychologist 

Anxiety and the Brain

Over thirty years of scientific research has supported the efficacy of cognitive behavioral therapies in the treatment of anxiety disorders, but it is only recently that technological advances have shed light on the neurological explanations for how anxiety disorders develop and why cognitive behavioral treatments are so highly effective.


An understanding of the brain can be extremely helpful when learning to manage uncontrollable, excessive anxiety, and therefore, this section will attempt to describe in general the brain mechanisms related to the experience of anxiety.




Our brains control our thoughts, feelings, and behaviors, but changing the way we think and changing the way we respond can also change brain structures and patterns of responding in the brain. This is referred to as neuroplasticity.


Being stuck in inflexible patterns of thoughts and behaviors are the problem in anxiety disorders, but by practicing new ways of responding to fearful situations, brain circuitry can be rewired to respond more flexibly to situations that cause anxiety.


Old patterns do not necessarily disappear, but rather new circuitry, new patterns of thinking, and new ways of responding are strengthened while old habitual patterns are weakened creating more flexibility of choice.




The amygdala is an almond-shaped structure in the brain found on each side of our cortex. The amygdala is responsible for the physiological component of anxiety in that it initiates the fight or flight response in the rest of the body.


Without the amygdala, we would not be able to have a fear response, and in fact, studies have shown that animals and humans with compromised amygdala functioning no longer have normal, adaptive fear responses to dangerous situations. On the other hand, those with a genetic vulnerability to having a sensitive amygdala may exhibit strong fear responses to any sign of danger.


When the amygdala senses danger, it acts as a protector and seizes control of our thoughts and behaviors so that we are focused on responding to danger. It sends an immediate alarm that can be automatically activated even before we have had time to think. This is why we can jump out of the way of a car before our thinking brain has even registered the danger.


The amygdala makes rough assessments for a quick anxiety response, which is adaptive in emergency situations, but may lead to inaccurate, false alarms. In dangerous situations, though, it is better to be safe than sorry.


The amygdala appears to respond in a preprogrammed way to certain fears such as snakes, spiders, and heights, but fears can also be learned.  The amygdala can learn to fear a new situation if it is paired with a distressing anxiety response and afterwards may continue to automatically send out an alarm response in error even if the situation is no longer dangerous.


It is the amygdala that is involved in the classical conditioning of fears.


To learn a less fearful response to a trigger, the amygdala must be activated and then presented repeatedly with a new learning experience where there is no danger despite uncomfortable, distressing feelings of anxiety. The amygdala seems to learn through experience, not logic, and through pairings or associations. 


Once the amygdala has initiated an automatic or conditioned fear response, it takes time for the body to settle down, even if the threat is no longer present and even if we tell ourselves that we are safe. This means that we may need to ride out the experience of a primary anxiety response while trying not to ignite a secondary fear response.


Thoughts from the cortex (see below) can help you ride out the anxiety ("This is scary but probably not dangerous") or set off a secondary anxiety response ("This anxiety means I'm in danger!") 


Techniques to Calm the Amygdala: 


Though some people seem genetically prone to having overly sensitive amygdala responses to danger, there are still techniques that can dampen the amygdala activation system.


Diaphragmatic breathing, aerobic exercise, and yoga can lower the intensity of the amygdala response. Regular aerobic exercise, yoga, and adequate sleep are also helpful in decreasing the overall sensitivity of the amygdala response.


For long term rewiring of the amygdala circuitry, the most effective intervention is repeated, prolonged exposure to the feared events, objects, experiences, or memories without any dangerous outcome.


The primary goal in therapy is not necessarily to be able to enter feared situations while calm but rather to face feared situations despite the anxiety. That is when true learning occurs in the brain. The short term discomfort is a necessary part of healing in the long run.




As described above, sensory experiences (sights, sounds, smells, tastes, physical feelings) can travel directly to the amygdala immediately igniting an anxiety response even before we have had time to think about what we've experienced. The part of the brain that does the thinking or the interpreting is the cortex.


The cortex is what people typically think about when we think about the brain. It is the thinking brain, the logical brain, the planning brain. It is the part of the brain involved in obsessing, worrying, ruminating, and dwelling.


The pathway from our senses to the cortex and then to the amygdala is slower and more thoughtful than the pathway straight to the amygdala. The cortex takes in information from our environment and interprets the world around us, and if it senses danger, it can send information to the amygdala which can then activate the fear response.


For example, while on a hike if you see a long, slender shape on the path, the amygdala immediately makes a rough assessment of the situation and interprets this threatening shape as a snake (better safe than sorry), and the body reacts automatically by jumping out of the way before the cortex has had time to register the shape as a stick.


Once the cortex interprets the object as safe, it sends a message to the amygdala but the amygdala response takes some time to terminate and furthermore adrenaline has already been dumped into your body system. Thus, the anxiety response may continue for several minutes to an hour depending on the initial level of amygdala activation. 


The cortex is also capable of igniting anxiety by generating its own thoughts and images without any stimulation from the environment. Worries and obsessions are essentially being created from within the cortex itself.


The cortex also has the ability to dwell and ruminate on these thoughts and images, whether they are real or not, which then activates the amygdala which then activates the fear response. 


The cortex can also plan ahead and foresee anxiety provoking situations in the future which leads to anticipatory anxiety.


In addition, the cortex can worry and ruminate about fearful situations in the past. In a sense, the cortex is capable of worrying about the past and the future, scaring the amygdala in the present.


Techniques to Calm the Cortex: 


As with the amygdala, neuroplasticity is seen in the cortex, meaning it is capable of change. The cortex responds to education, reason, logic, debate, and experience, and thus fears can be explored and challenged and new beliefs can be developed and practiced.


The most effective way to rewire the circuitry of the cortex is to practice thoughts and interpretations that allow for a new, stronger, pathway to be developed in the brain. This is referred to as the “survival of the busiest,” where the circuitry or pathway in the brain that is used the most becomes the strengthened whereas those that are not being used as much become weaker.   


Therapy techniques that might help rewire the cortex (the thinking brain) are those that identify and challenge thoughts and interpretations that induce anxiety.


Logical approaches that use scheduling, planning, and problem solving also seem to help calm the cortex.


Understanding where these beliefs came from can also help diffuse some of the power behind the thoughts.


For some, the cortex may have fallen into the habit of generating anxiety provoking thoughts and then gets stuck on this “anxiety channel,” which activates the amygdala. The realization that these thoughts are not dangerous and are not productive and that it is not helpful to listen to these anxiety provoking messages can provide great relief.


Mindfulness techniques can help to develop the ability to allow thoughts to pass by so as to not activate circuits that induce anxiety.