The Guide to How Anxiety Works: Using Neuroscience to Explain Anxiety
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Before we dive into this extensive and in-depth article, let us imagine a short scenario to get a better understanding of how anxiety works, the anxiety process and how anxiety plays out in our daily lives.
You plan on doing some shopping so you hop in your car and head to the mall. As you approach the parking lot, you begin feeling anxious. By the time you park your car, your heart is thumping and your stomach is in knots. Your mind begins to replay images of the last time you were here and how anxious you felt. You think “It will happen again,” “Why am I so afraid?” “What if I have to leave?” “What if everyone notices me freaking out?” By the time you walk from your car to the front door of the mall you’re on the verge of a panic attack; thoughts racing, heart pounding, stomach churning and your hands clammy as you reach for the door.
What is happening?
Why do you feel this way?
Anxiety can often seem unpredictable, uncontrollable and even automatic at times.
Understanding the processes behind anxiety may seem complicated.
We may believe this understanding to be limited to doctors or psychiatrists.
But we can all develop a better understanding of how anxiety works and improve our lives in the process.
In order to explain how anxiety works, I will be using the latest research and scientific understanding of the brain – neuroscience – to explain the processes behind anxiety and answer the most common questions many of us want answered.
- What happens when we are anxious?
- How does our brain create anxiety?
- What are the effects of anxiety on the brain and nervous system?
- Which neurotransmitters are associated with or involved with anxiety?
- Why do certain people, places or things trigger anxiety?
- What happens during the fight-or-flight response and how does it relate to anxiety?
Understanding how anxiety works can shine a light on an area where most of us are in the dark.
When we understand how anxiety works, we can better understand why certain approaches and strategies reduce or eliminate our anxiety.
When we understand the processes behind anxiety, we develop a clearer picture of the anxiety response and how it plays out in our lives.
When we see that our brain is initially responsible for our anxiety response and our body is simply responding in the ways it is meant to respond, we can develop greater acceptance and less fear surrounding the feelings of anxiety.
So… let's dive in and shine a light on anxiety and the brain using neuroscience as our guide.
Please note: this article is not meant to be taken as medical advice. The content provided is for informational purposes only. Consult with your doctor or healthcare provider before changing your diet, prescriptions, or making any other health-related changes.
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A Quick Note
I've intentionally simplified certain brain and body processes and made an effort to avoid overly scientific terms wherever possible.
Hopefully, this makes the article not only easier to read but more enjoyable as well.
As an example; we will be using the term “cortex” throughout this article to describe the many processes of the cerebral cortex, instead of stating the specific areas of the cortex such as the anterior cingulate cortex or orbitofrontal cortex (which is a mouthful to say the least).
Also, although the brain and bodily systems function as a whole to communicate, we will be focusing primarily on the areas directly associated with anxiety, while ignoring others.
Overall, this should make the article easier to follow and understand, without taking away from the information and the science behind it.
Neuroscience and Anxiety
The incredible amount of progress in the field of neuroscience over the past few decades has led to a vast increase in our knowledge of how the brain works.
As a result – we now have a greater understanding of anxiety, how the brain creates anxiety and its resulting physical and emotional symptoms.
In fact, anxiety is the most well understood of all the so-called “disorders.”
We currently have a better understanding of the causes and treatments available for anxiety as well as the potential future treatment options.
Neuroscientific research on the brain and anxiety centers around the brain's detection and response to threats and how we create and respond to fear.
According to the research; the brain detects and responds to threats through specific areas in the brain and physiological changes in the brain and body. These changes include the infamous “fight-or-flight” response and the release of key neurotransmitters and hormones.
The threat our brain detects and responds to can be physical; such as being in physical danger – or mental, such as thoughts and images related to a threatening event, or experiencing a loss of our sense of homeostasis (mental or emotional balance).
These potential threats can be real or imagined.
Quite often these potential threats are imagined or at least exaggerated out of proportion.
The brain and body respond to these imagined threats in the same way as a real threat.
Research also shows the important role of stress in anxiety.
Intense stressful experiences and prolonged stressful situations can often lead to symptoms of anxiety, physical and mental tension and panic attacks.
The Latest Research
In this article, we will use the latest research in neuroscience to explain how the brain creates anxiety and what is happening in our brain and body when we experience anxiety.
I have based the information provided on the latest scientific research wherever possible. As of today, this is the furthest understanding we have about the brain and anxiety as far as I am aware.
But science is always pressing forward.
The knowledge of ourselves, our brains and our mental and emotional states is always expanding.
I will do my best to update this information as it arrives.
The Brain and Anxiety
Anxiety can seem to originate from complex sources with a wide variety of symptoms.
Typical symptoms can include: a fast-beating heart, fearful thoughts, obsessive thinking, sweating, worry, mental or physical tension and panic – to name only a few.
Anxiety can also seem to come out of nowhere, occur automatically or come from outside of us.
Our brains have evolved to take in information from experiences and our surroundings while keeping a watchful eye for potential threat or danger.
While anxiety can seem to start in the body or even come from situations outside of us – in reality, all anxiety starts in the brain, regardless of where we think it started or what seemed to trigger it.
There are key areas of the brain responsible for keeping us safe and avoiding potential danger.
These areas of the brain and nervous system also help to determine how we respond to threatening situations, through our interpretations and our actions.
While these areas have many important roles – we will focus primarily on their direct relationship to anxiety, panic and fear.
Below I will briefly summarize several important areas of the brain.
Later we will discuss two in particular – the amygdala and the cortex – in more detail.
Important Areas of the Brain in Anxiety: A Brief Overview
THE LIMBIC SYSTEM
A system of closely related structures in the brain primarily responsible for our emotions and memory.
- Thalamus: like grand central station of the brain, the thalamus takes sensory information and “passes” it to the proper channel in the limbic system or cortex
- Hypothalamus: responds to stress from other parts of the limbic system (particularly the amygdala) by releasing stress hormones and activating the nervous system
- Hippocampus: important in the registering of details and facts, and for the formation of memory
- Amygdala: the key player in fear and anxiety, registers emotions with a strong focus on threatening or scary ones, works to avoid potential dangers based on past experiences, uses “triggers” to avoid certain people, places or things; communicates with the hypothalamus to start the stress response
THE CORTEX
Responsible for our thinking and perceiving – the cortex allows us to think, make plans, attach meaning and interpret experiences.
The cortex also handles all the higher-level functioning of the brain – rational thinking, using logic, thinking about thinking, etc.
Considering how our thoughts and interpretations often create (or intensify) our feelings of anxiety; understanding the cortex’s role in anxiety should be easy to see.
There are 4 parts to the cortex – each with different roles – but all parts of the cortex work together.
For the sake of brevity and simplicity, I will refer to all the parts of the cortex simply as – the “cortex.”
THE BASAL GANGLIA
The basal ganglia are responsible for many processes in the body.
In terms of anxiety; the basal ganglia are involved in the level of energy, arousal and motivation felt.
Dopamine plays a large part in the motivation factor in the BG, while GABA keeps these energy levels in check.
High dopamine (and norepinephrine) and low GABA in the basal ganglia can cause physical and mental tension, perfectionism, and high drive.
This combination of tension, drive and perfectionism often leads to burnout and high levels of anxiety.
The basal ganglia are also responsible for the formation of habits.
This is important considering that many negative habits can cause anxiety.
Our habits can also keep anxiety in place and can be an important factor when working to overcome anxiety.
The Two Pathways to Anxiety
There are 2 major pathways to anxiety.
One path to anxiety occurs when an external stimulus (or trigger) activates the amygdala – which activates the stress response (fight-or-flight response). We often experience this as a knee-jerk (automatic) anxiety/fear response and it may seem to occur for an unknown reason.
Another possible path to anxiety is when our cortex processes (thoughts, perceptions or interpretations) trigger the amygdala – which starts the anxiety/stress response. This often occurs when we obsess, worry or imagine threatening scenarios or interpret experiences in a threatening way. The amygdala responds as if the thought or imagined situation were real.
Understanding how anxiety works in each pathway can help us recognize which area is causing us trouble.
Each path responds to different therapies and techniques.
Knowing which we are dealing with can be extremely valuable.
For example; if our anxiety is cortex based (meaning our thoughts are the problem) than a cortex based therapy such as CBT could work well.
If our anxiety is amygdala based (meaning we have a spontaneous fear/anxiety response to situations or particular phobias – often without knowing why) than something like psychotherapy or techniques like mindfulness can be more useful.
The amygdala kick starts the fight-or-flight response and is the anxiety initiator – therefore both pathways lead to the amygdala. By understanding where our anxiety first begins (whether it's our thoughts frightening the amygala, or an external trigger), we can determine the strategies that will be most effective for us.
Below we’ll be diving more into each pathway.
The Amygdala
The amygdala is an almond-shaped structure within the brain. Although there are 2 amygdalae (one on each side of the brain) – we will use the common term amygdala.
The amygdala is an essential part of the limbic system; the amygdala receives information from the outside world from the thalamus, forms memories with the hippocampus and starts the stress response (fight-or-flight) with the hypothalamus.
Our conditioned fear responses, phobias and anxiety triggers are directly associated with the amygdala.
The amygdala can become activated (become triggered or feel threatened) and lead the body to respond before we can even think about what is happening.
Unlike the cortex which can take a second or two to think about something and respond – the amygdala can respond almost immediately based on conditioned fear responses and external triggers our cortex may not even be aware of.
The amygdala functions by taking only the most basic, “raw” data available and responding in fractions of a second. The cortex is usually left playing catch up.
This nearly instant process is for a good purpose.
Think about when you are driving and a car swerves over into your lane; the amygdala can instantly determine a potential threat, making your body respond and react by hitting the brakes or swerving out of the way before your thinking mind (cortex) has time to figure out what happened.
The Amygdala Playing Tricks
Our amygdala isn’t perfect and can play tricks on us. Since the amygdala is only taking in raw data it can often mistake non-threatening things or situations for dangerous ones.
Let's use an example:
You get home alone late in the evening, the house is dark. You walk upstairs and through the darkened hallway, headed to the bathroom at the end of the hall. As you pass your bedroom, you believe you see someone out of the corner of your eye standing in your darkened room. You tense up and feel instant fear. Your cortex didn’t get enough information to determine what it was you saw but your amygdala is already preparing your body for fight or flight. Your palms begin to sweat, you feel fear and anxiety. At this point you may use your cortex to rationalize the situation, thinking “it was probably nothing,” or the cortex could make it worse by imagining all kinds of scary scenarios. You decide to check it out. You walk into the bedroom and turn on the overhead light. It turns out it was only a floor lamp.
The Amygdala & the Stress Response
In the example above; our amygdala began activating the stress response based on very limited “data” – a fleeting image out of the corner of the eye.
Once the stress response is triggered we often quickly feel anxiety, fear and panic.
The amygdala initiates the stress response – otherwise known as the fight-or-flight response.
The amygdala responds to threatening situations (real or imagined) by communicating to the hypothalamus to release certain hormones and neurotransmitters, starting the stress response.
The amygdala also activates the sympathetic nervous system; increasing blood flow, heart rate and respiration, among other processes.
Both systems, initiated by the amygdala’s response to a potential threat, prepare the body to fight or take flight (flee or run away).
We will discuss the stress response and the actions of the sympathetic nervous system in more detail later in this article.
Both are important factors for understanding how anxiety works.
The Role of the Amygdala in Anxiety & Fear
One of the primary roles of the amygdala is in the processing of emotional responses; such as anxiety, fear and aggression.
The amygdala also plays an important role in memory, especially emotional memory and trauma.
The amygdala has additional roles in processes such as sexual behavior and bonding but we will only discuss the amygdala's primary role in fear and anxiety, its role in creating anxiety-producing memories and its role in registering emotions.
One of the major roles of the amygdala is attaching emotional significance to objects, situations or experiences. The amygdala “labels” experience based on emotional responses to the particular experience and helps to create memories with the labels it has prescribed.
While the amygdala registers all emotions – it focuses more on scary and threatening ones.
The amygdala places extra emphasis on the memories it has associated (labeled) with threatening emotions.
The amygdala does this to protect us and help us avoid potentially dangerous situations.
It does this based on things (events, people, objects, experiences) that scared us in the past or things it associates with threatening emotions.
We can think of the amygdala as our personal protector.
The amygdala’s main goal is to keep us safe.
So attaching extra emphasis on scary or threatening memories should make sense if we think about it.
If we are in a dangerous situation such as driving carelessly on an icy road and we wreck our car and injure ourselves – the amygdala will register our fear and stress based on the event.
Next time we are driving on an icy road the amygdala may increase our alertness (and increase our stress) so we focus better and drive more carefully than we did the last time.
There can be issues with the amygdala’s processing of threatening memories.
The amygdala doesn’t “think” about or rationalize the situation – it responds emotionally.
Therefore, it can exaggerate the severity of a situation or place anxiety-producing significance on a seemingly mundane object or event.
I attended a “Neuroscience and Anxiety” seminar a few years ago where the speaker discussed a patient with PTSD.
This patient was an Afghanistan war veteran.
The patient was doing well when he suddenly began experiencing intense anxiety in the morning.
He couldn’t figure out what was causing the anxiety.
When he began examining his morning routine, he discovered the soap he had recently bought, and was using in the shower each morning, was the same soap he used while fighting in Afghanistan.
The smell of this soap had triggered fear and anxiety based on his experiences in the war.
When he got rid of the soap, his anxiety went away.
Anxiety Triggers
In the story above, the amygdala placed emotional significance on the soap because it associated the soap with a threatening situation – fighting in a war.
In other words – the soap became an anxiety trigger.
Anxiety triggers serve a purpose (to avoid danger) but the amygdala often places threatening significance on people/places/things that aren't dangerous in and of itself – such as soap.
The amygdala pathway is closely associated with phobias.
Our fear/phobia of a particular person, place or thing is directly related to these anxiety “triggers” created by the amygdala, often at an early age.
Someone who had a threatening or scary experience with a dog as a child may develop a phobia of dogs later in life.
This is because dogs have been “labeled” as dangerous by the person’s amygdala – thus becoming an anxiety trigger.
Anxiety triggers can be anything; smells, sounds, objects, places, people, or anything else. As I mentioned before, the amygdala is responding emotionally, not rationally, so it can place emotional significance on anything associated with the threatening event.
A woman sexually assaulted at a party while Led Zeppelin played on the stereo may have panic attacks afterward whenever she hears Led Zeppelin.
A young Army private home from war may become terrified of the sound of fireworks on the 4th of July that sound eerily similar to the sound of explosions and gunfire.
In both cases neither trigger is dangerous in the present context – it’s the association created by the amygdala between the trigger and threatening situation of the past that is causing fear and anxiety in the present.
The Amygdala & Trauma
The amygdala pathway to anxiety is closely linked to trauma and PTSD.
The amygdala’s role in placing emotional significance on events and forming emotional (anxiety/fear producing) memories is at the core of most trauma.
Trauma can link itself to particular memories and triggers. If we’ve experienced trauma, we may be conscious (aware) of these memories and triggers or they may be unconscious (we are unaware of them).
When we are aware of traumatic memories, we may consciously avoid situations and people related to the memory.
For example:
If we were physically assaulted while walking down a city street at night; in the following weeks or months, we may avoid that street or area, avoid walking alone or even avoid walking at all. This fear and anxiety related to the situation and our avoidance of similar situations may last days, weeks, months or even longer depending on how we handle our experience and the trauma we have faced.
If we are unaware of the memory and it remains in the unconscious (or subconscious) – we may respond to certain situations with anxiety and fear and we may not fully understand why.
We often repress trauma experienced in early childhood and the trauma remains in the unconscious.
This can often lead to unconscious fears, phobias and avoidance of particular people, places or things later in life.
In either situation, the amygdala is responding based on the emotional significance it has attached to the prior event and is functioning in a way to help us avoid experiencing the same threatening/painful situation.
Retraining the Amygdala
The good news is we can retrain the amygdala.
We can teach the amygdala that the anxiety triggers it has created are not dangerous in the present experience.
We can also let go of or come to terms with past traumas and traumatic memories.
While we may have experienced a real traumatic event in our lives, we need not continue reliving it or associate the present experience with the past.
Two powerful ways to retrain the amygdala and come to terms with our phobias and traumas are through Psychotherapy (particularly trauma-focused therapy) and Exposure.
Psychotherapy can help us uncover and integrate unresolved traumas and memories.
When we uncover (bring to awareness) unresolved traumas, we will no longer continue reliving past experiences or become fearful and anxious for unknown reasons.
The amygdala can then learn to let go of its intense association between the past event and present events, objects, people and experiences.
Exposure can help us face what we are afraid of and create new (safer) experiences and memories.
Using the example of the fear of dogs above; we could use exposure to our fear of dogs by taking time to pet and play with a friendly Labrador.
We can retrain the amygdala to see that dogs can be loving and friendly and need not ignite our anxiety.
Over time and with repeated exposure, the amygdala will no longer associate all dogs with threat.
The goal of retraining the amygdala is to show the amygdala we are safe now. What we are experiencing now is not the same as what we experienced in the past.
We may have experienced trauma as a child growing up in an abusive household – but we are safe NOW.
We may have experienced a dog that scared us when we were young – but we can be safe petting a dog NOW.
We may have experienced the traumas of war while in the military – but we are home and safe NOW.
The Cortex
The cortex – also known as the cerebral cortex – is the part of the brain most of us think of when we think of the brain.
This is the area responsible for thinking and perceiving.
The cortex itself comprises several important structures including: the insular cortex (or insula), the cingulate cortex, the orbitofrontal cortex and the prefrontal cortex.
For this article, we will simply use the generic term “cortex” to avoid confusion.
The cortex is involved in many essential mental and emotional processes:
- Thinking and perceiving
- Processing sensory information (information coming in from the outside world)
- Attaching meaning to perceptions
- Using logic and reasoning
- Understanding and interpreting situations
- Planning and responding to events and experiences
- Using the imagination
The Cortex and Anxiety
As we mentioned already, the cortex is responsible for our thinking and perceiving.
Given this fact, the cortex is responsible for constructing our reality.
What we perceive, what we think and what we think about what we perceive (how we interpret experiences/events) forms our construction of reality and the subjective (personal) reality we experience.
We use our cortex to think about and interpret experiences as they occur.
We think about, imagine or remember experiences in the past or future.
We also create thoughts and images beyond our perceptions.
What we think about, how we interpret our experiences, and even what we picture and imagine – is our experience of reality. But…. the reality we have constructed may not be accurate.
Our thoughts can be false – our interpretations can be misguided.
Let’s use an example:
You've been with your boyfriend for 6 months. While you’re at work one day, your boyfriend texts you the following message: “We need to talk later”
You text back but he doesn’t respond.
Your thoughts and imagination (cortex) begin going wild with possibilities.
- Does he want to break up with you?
- Did he cheat on you and now wants to come clean?
- Why did he say it like that?
- Is he ignoring you now?
What makes you come to these scary conclusions based on 5 simple words?
These thoughts get the attention of the amygdala which sees the current situation as threatening (fear of being abandoned or betrayed) and starts the stress response – which turns into anxiety and if it continues, panic.
Let’s try a different example:
You’ve been struggling with social anxiety.
Recently, you’ve been avoiding going out but some friends invite you to a concert at a local club.
It’s a band that you really like so you decide to go.
Hours before the show you begin thinking about what could happen when you go.
- What if you make a fool of yourself?
- What if people can tell you're uncomfortable?
- What if you want to leave but can’t?
- What if there are too many people there?
- What if you panic?
Here you are again using scary thoughts with anxiety-producing mental images.
You imagine scary scenarios playing out.
Again the amygdala is activated by your thoughts and mental images – even if they are completely imagined and have no basis in actual reality.
Again you become anxious.
If you continue down this path, you may cancel your plans completely to avoid the anxiety.
These are just two examples but the method behind the creation of anxiety is the same regardless of whether the situation is real or imagined.
Even if a real negative situation occurs – such as finding out you are getting laid off from your job in 2 weeks – your thoughts and interpretations can make the situation much worse and spark intense anxiety.
You may think: “I’ll never find another job,” “How will I pay the bills?” “I’m going to be living on the streets,” etc.
How The Cortex Anxiety Process Works:
EXPERIENCE
(Real or Imagined)
INTERPRETATION/
THOUGHTS
(About the Experience)
AMYGDALA is ACTIVATED
(Sees the Situation as Threatening)
STRESS RESPONSE/
FIGHT-OR-FLIGHT
ANXIETY
The cortex doesn't necessarily need actual experiences to activate the amygdala.
Thoughts and mental imagery unrelated to actual experience can be enough to activate the amygdala if the amygdala believes them to be threatening.
One important factor to remember: the cortex can get anxiety started but it cannot create anxiety on its own.
The amygdala causes the actual sensations and experiences of anxiety.
The amygdala is activated when we use threatening thoughts, imaginings and mental images created by the cortex pathway.
The Cortex & Amygdala Connection
Our thoughts and interpretations coming from the cortex can create anxiety because of the cortex’s connection with the amygdala.
The amygdala constantly monitors the cortex for potentially threatening interpretations.
The amygdala can also influence and take over the cortex by making the cortex focus on specific things in dangerous or threatening situations.
While the connection between the cortex and the amygdala goes both ways – the cortex has far fewer connections to influence the amygdala than the amygdala has to influence the cortex.
This is the reason we typically can’t think our way out of a panic attack or reduce our anxiety through thoughts alone during experiences of severe anxiety.
The amygdala responds to experiences more quickly than the cortex can process the information. Once the amygdala is activated and the stress response begins, it is much harder to calm ourselves down than it is prior to the amygdala’s activation.
This may sound like there isn’t much we can do to keep the amygdala calm but there is.
The key is what we focus on, think about and how we interpret our experiences.
Creating Anxiety with Our Thinking
Cortex interpretations can either help the amygdala stay calm or worsen the amygdala's response to situations and experiences.
The amygdala can often become activated simply by our obsessing negative thoughts.
Those of us with strong imaginations work ourselves up with vivid images of every terrible thing we can think of, even when we are physically safe.
When the amygdala is only slightly activated based on a situation we are in, the cortex can send the amygdala into panic mode.
For example; you are walking alone down a city street late at night, you are already slightly on edge but then you begin thinking thoughts such as: “What if someone attacks me?” “What if I get lost?” “What if I run into some bad people?”
The next thing you know you're experiencing intense anxiety and fear.
This is entirely based on your thoughts/interpretations of the situation.
Therapies and techniques that focus on our cognitive processes – thinking, interpretations, memory of experiences, mental habits – are possible solutions to the anxiety created by the cortex pathway.
Cognitive Behavioral Therapy (CBT) is a popular form of cognitive therapy that has shown to be effective for anxiety in particular.
Acceptance and Commitment Therapy (ACT) is another great option for cognitive-based anxiety (and one I personally like a lot).
Neurotransmitters and Anxiety
We now have a better understanding of the two major players involved in anxiety – the amygdala and the cortex.
So what about neurotransmitters and “chemical imbalances,” every doctor and psychiatrist’s favorite terms when discussing anxiety with their patients?
While the “chemical imbalance” theory is often debated – there does seem to be a correlation between the number of specific neurotransmitters available in different parts of the brain and our level of anxiety, fear, tension, panic, negativity, worry and our response to experiences.
Neuroscience also confirms that neurotransmitters can have a direct influence on our anxiety levels and is an important part of understanding how anxiety works.
There can be many reasons for having low or excessive amounts of certain neurotransmitters in the brain.
These reasons can include:
- Trauma: experiencing physical, emotional, or mental trauma can lead to increases in stress hormones and reduction in more calming neurotransmitters such as serotonin
- Chronic Stress: similar to trauma, chronic stress can reduce key neurotransmitters
- Nutrition/Diet: what we eat has a direct effect on how we feel and the health of our brains and bodies
- Illness/Disease: many illnesses can lead to an imbalance in different neurotransmitters
- Poor Sleep: sleep is vital to the production of neurotransmitters and overall health
- Genetics: some of us are simply born with lower availability of specific neurotransmitters or may have fewer receptors in the brain, such as fewer serotonin receptors than the average person
Keep in mind, having an imbalance of neurotransmitters can cause anxiety – but the area in the brain where these neurotransmitters are low or excessive affects the type of anxiety we may experience.
Below are the key neurotransmitters involved in anxiety in all of its forms.
For more on anxiety and chemical imbalances, check out our article Biological Causes of Anxiety: Root Causes of Anxiety Part 2
Serotonin
Serotonin is an important neurotransmitter that has a wide-ranging impact on anxiety.
Serotonin’s key function is regulating brain and bodily systems.
Besides playing a role in anxiety and stress, serotonin also regulates sleep, mood and appetite.
When we are low in serotonin, we lose much of this regulation.
We may have trouble sleeping, we may lose our appetite and our mood may become overly negative or we may be unable to pull ourselves out of a depressed/dark mental state.
This loss of regulation due to low serotonin can also reduce our ability to calmly assess potential threats and respond in a healthy way. We may blow situations out of proportion, respond irrationally or become overly sensitive and emotional.
When visiting our doctor for anxiety (or depression) they will often discuss a chemical imbalance – by this they usually mean low serotonin.
Doctors will typically prescribe an SSRI – such as Prozac, Paxil or Lexapro – as first-line treatment options.
SSRIs and other similar drugs work to increase the amount of serotonin available in the brain.
Stating that we have low serotonin doesn’t describe the whole picture or serotonin’s wide-ranging effects on anxiety.
Where serotonin is low in the brain determines the anxiety symptoms we experience.
While not as often discussed, excessive amounts of serotonin can also cause anxiety – particularly social anxiety and social phobia.
Excessive serotonin can also cause an imbalance in other neurotransmitters such as Dopamine and Norepinephrine, leading to loss of motivation and drive and poor concentration and cognitive function.
Low Serotonin in the Limbic System
- Worry
- Negativity
- Overly sensitive to possible threats
Low Serotonin in the Cortex
- Irrational response to situations and events
- Poor impulse control
- Feeling stuck in negativity (having a “dark mood”) or unable to see things positively
- Inflexible attitudes and behaviors
- Loss of emotional control
- Constant underlying worry
High/Excessive Serotonin
- Has been linked to social anxiety and social phobia
- Linked to overall increases in anxiety and panic
Dopamine
Dopamine is a neurotransmitter that plays a role in many important functions. It is well known for its role in motivation, focus and feelings of pleasure.
Low amounts of available dopamine in the brain can lead to cognitive issues such as trouble concentrating or scattered thoughts.
Low dopamine can also lead to an absence of good/positive feelings or a lack of pleasure.
Social anxiety; lack of interest in social interactions, social phobia and social avoidance, have been linked to low dopamine in the brain.
Symptoms of high/excessive levels of dopamine can vary depending on the location in the brain where dopamine is high.
Overall, we associate high/excessive dopamine with perfectionism, panic attacks and intense motivation that can eventually lead to burnout. Chronically high dopamine (excessive dopamine in the brain for long periods of time) can lead to delusional states and even psychosis.
Trauma and periods of extreme stress can often increase levels of dopamine in the brain – which often leads to anxiety and panic attacks.
Chronic drug use with drugs that affect dopamine directly, like cocaine and methamphetamine, can cause rapid and intense increases, followed by significant decreases in the levels of dopamine in the brain.
Dopamine can cause anxiety when it is too low or too high. The part of the brain where dopamine is low or high can determine the symptoms experienced.
High/Excessive Dopamine in the Basal Ganglia
- Perfectionism
- High drive
- High motivation
Low Dopamine in the Basal Ganglia
- Loss of interest in things, other people, activities, etc.
- Lack of motivation
- Low feelings of pleasure or complete loss of pleasure
High/Excessive
Dopamine in the Cortex
- Panic attacks
- Anxiety
- Overly focused on details
- Long-term high dopamine in the cortex can lead to psychosis
Low Dopamine in the Cortex
- Trouble focusing
- Scattered thinking
- Impulsive thinking and behaviors
- Addiction
Norepinephrine
Norepinephrine is an important hormone and neurotransmitter responsible for many functions throughout the brain and body.
To describe every process norepinephrine is involved in would be an article in itself.
Overall, norepinephrine’s main function is to prepare and mobilize the brain and body for action. In the brain it does this by increasing alertness, focus and mental vigilance. In the body, it increases available energy and directly affects different bodily processes when needed.
Norepinephrine is the key player in the fight-or-flight response.
The sympathetic nervous system uses norepinephrine to prepare the body to fight or run (flee).
The sympathetic nervous system also uses norepinephrine to affect the organs of the body directly; such as increasing the heart rate and blood pressure, redirecting blood flow to the extremities (muscles of the arms & legs) and producing more glucose for energy.
While the stress response process is necessary for our survival – it’s relatively easy to see how this could create problems for many of us.
Norepinephrine is an energizer and sets the tone for tension in the brain and body.
Those of us with anxiety are often already tense and overly stressed – it doesn’t take much additional norepinephrine to send us over the edge into anxiety and panic.
Norepinephrine becomes a problem when there is too much – creating tension and anxiety.
Depending on where in the brain or nervous system there is too much norepinephrine will determine the symptoms.
Chronically high levels of Norepinephrine can stem from excessive stress, abuse or trauma, or lifestyle choices.
Low levels of norepinephrine can be an issue as well.
Much like low dopamine, low norepinephrine can lead to many cognitive, energy and motivation related issues.
High Norepinephrine Throughout the Brain
- Over-arousal
- Mental and physical tension
High Norepinephrine in the Basal Ganglia
- Feeling “wired”
- Restlessness
- Unable to relax
High Norepinephrine in the Cortex
- Hypervigilance
- Scattered thoughts
- Chaotic thinking
High Norepinephrine in the Sympathetic Nervous System
- Overall sense or feeling of “doom”
- Panic attacks
GABA
Gamma-Aminobutyric acid – otherwise known as GABA – is the primary inhibitor in the brain and nervous system where it acts to slow or stop neurons from firing.
GABA reduces excitability throughout the nervous system.
GABA is often described metaphorically as the nervous system’s “STOP” signal vs glutamate’s “GO” signal.
Low levels of GABA lead to over-activity in the brain and nervous system – which can lead to anxiety, tension, restlessness and panic. Insufficient levels of GABA can lead to an imbalance and an overall increase of excitatory neurotransmitters like glutamate and dopamine.
GABA has a close link to anxiety and panic attacks and there are many prescription anti-anxiety medications that work by increasing the amount of available GABA in the brain and nervous system.
The most popular of these are Benzodiazepines; which include Xanax, Valium and Ativan.
Most GABAergic drugs produce feelings of relaxation and a reduction in anxiety.
Other drugs such as sleeping pills, muscle relaxers and anti-seizure medications also affect GABA as well as herbs such as Kava and alcohol.
Insufficient GABA in the brain leads to an imbalance in other neurotransmitters.
Low GABA in the Brain
- Anxiety
- Agitation
- Glutamate imbalance
- Neurotransmitter imbalance (which can lead to other problems depending on which neurotransmitters are out of balance)
Low GABA in the Basal Ganglia
- Panic attacks
- Excessive energy/tension
The Autonomic Nervous System
The autonomic nervous system (ANS) is a control system responsible for regulating the body’s unconscious actions.
The ANS is the mechanism in charge of the fight-or-flight response (or stress response) and comprises two complementary parts: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS).
The SNS and PSNS work together to regulate many of the body’s reactions and responses during this period of fight-or-flight including: heart rate, digestion, breathing, energy production and blood flow.
We can think of the SNS as the activator/initiator of the fight-or-flight response, directing the organs to respond and take action – while the PSNS activates the opposite response, “rest and digest”, and returns the body to calm and homeostasis after the stress response.
The sympathetic and parasympathetic nervous systems have opposing actions that complement each other.
For example; the SNS will increase heart rate and decrease digestive activity – while the PSNS will slow the heart rate (or return it to normal) and increase digestive activity.
While the actions of the autonomic nervous system are automatic and operate primarily without our control – we can take over control of the ANS on purpose using various techniques.
The Sympathetic Nervous System (SNS)
The sympathetic nervous system (SNS) originates in the spinal cord and is responsible for activating the changes that occur during the fight-or-flight response.
The SNS alters the functions of the organs such as the heart, liver and lungs to prepare the body to act – either to fight or flight (run or flee).
The SNS is activated by the hypothalamus – which is activated by the amygdala (as we discussed above).
The pituitary and adrenal glands release hormones and brain chemicals (neurotransmitters) such as norepinephrine, epinephrine and cortisol once the SNS is activated.
When we experience the physical symptoms of anxiety and panic such as: shaking, sweating, fast shallow breathing or increased heart rate – we are experiencing the activation of the sympathetic nervous system (SNS).
When our heart is pounding and our hands are shaking because of the fight-or-flight response – which is an intense activation of the SNS – we may become very anxious and if we fear the sensations, we may experience a panic attack.
Panic attacks are often a fear reaction to the activation of the SNS – through our fear we may interpret a pounding heart to be the beginning of a heart attack.
Activation of the SNS: Physiological Changes
All the physiological changes that occur by the activation of the sympathetic nervous system serve a purpose – to give the body increased energy and strength to fight or to run.
Certain bodily processes are accelerated while other processes are reduced/slowed, to give primary importance to our personal safety by preparing our body for fight or flight.
Below are some physiological changes that occur during the activation of the sympathetic nervous system, as well as the purpose of the changes and the possible symptoms we may experience based on our interpretation of the bodily sensation.
Physiological Change
accelerated heart rate and increased blood pressure
Purpose
increases blood flow and supplies extra energy
Possible Anxiety Symptom
pounding heart
blood flow is diverted away from the digestive system
blood is rerouted to the limbs and muscles
stomach pains/knots or nausea
more oxygen is taken into the lungs
allows for more oxygen exchange for energy
panic breaths/ lightheadedness
pupils dilate
allows more light to enter the eye for focused/far vision
tunnel vision
the liver produces extra glucose
supplies additional energy
headache/blurred vision/trouble thinking clearly
While we can understand the purpose behind many of these physiological changes, our reactions and interpretations of these changes when they occur can lead to anxiety and panic.
Understanding how these processes work and why they happen can greatly reduce our fear of them.
It is also an essential part of understanding how anxiety works and the neuroscience of anxiety.
The Parasympathetic Nervous System (PSNS)
The parasympathetic nervous system (PSNS) originates in the brain stem (in the medulla in particular) and activates the “rest and digest” response.
The PSNS is responsible for returning the body to homeostasis (a calm resting state) after the fight-or-flight response.
One of the primary nerves in the PSNS is the vagus nerve, which communicates between the brain and the body.
The vagus nerve can direct the function of the organs such as the heart, lungs and digestive system to balance the activation of the sympathetic nervous system.
The vagus nerve with the PSNS, promotes normal (resting) function by calming action in the body started by the SNS.
This includes: reducing the heart rate, slowing breathing and sending blood flow back to the stomach for digestion.
The PSNS is calm after the storm – but the calm doesn’t happen immediately.
After the sympathetic nervous system has started the fight-or-flight response it can take time before the parasympathetic nervous system brings everything back to normal – even if the danger (real or imagined) has passed.
There are actions we can take to improve the response of the parasympathetic nervous system after a stress response.
We can also control the PSNS through stimulating the vagus nerve – giving us the ability to prevent the stress response before it starts.
Taking Control of the PSNS
Like the sympathetic nervous system – the parasympathetic nervous system functions automatically without our need to control it. However, there are several techniques and practices that allow us to activate the PSNS – reducing the time spent in the fight-or-flight response or preventing the response entirely.
We provide the techniques for stimulating the PSNS throughout this site.
The techniques include; meditation, deep belly breathing or diaphragmatic breathing and relaxation techniques.
The fight-or-flight response is vital to our survival, but the response is not always necessary.
Through the practices mentioned above, we can take control of our ability to prevent exaggerated responses to non-threatening situations.
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Fight or Flight Response (The Stress Response)
I’ve mentioned the fight-or-flight response – also known as the stress response – many times throughout this article with brief explanations so far.
Now we will go a little more in-depth into how the fight-or-flight response operates.
Understanding how the fight-or-flight response works is an important part of understanding how anxiety works.
To put its function into the simplest terms: the stress response is a system to get you energy when you need it. In most cases, this would be a dangerous or threatening situation – whether it is real or imagined.
The stress response can function for any length of time (although it will always end) depending on the situation and the response needed.
This could be short bursts such as situations needing a quick reaction or powerful sustained bursts, such as during extended stressful situations.
The amygdala is always the initiator of the fight-or-flight response (as discussed above).
The amygdala receives information from the outside world (through the thalamus), through memory (amygdala based trauma) or through our thoughts and mental images (the cortex).
When we encounter a situation that the amygdala has labeled as threatening it signals to the hypothalamus to activate the stress response.
Once the amygdala detects a threat to our safety and activates the hypothalamus many reactions and chemical processes occur.
Below I’ve provided a visual representation of the stress response to give you a better idea of what is happening. Often having a visual representation can make it easier to get a picture of how something works.
The fight-or-flight response in itself doesn’t necessarily create anxiety, but the continued release of adrenaline, cortisol and other hormones can put us on edge.
The additional energy created can make us feel anxious and the physical symptoms can be uncomfortable and misinterpreted.
Repeated stress responses can inevitably lead to symptoms of chronic stress such as anxiety, fatigue and illness.
The Effects of Chronic Stress on the Brain and Nervous System
The stress response described above provides the energy we need in dangerous or life-threatening situations.
We receive this extra energy through the release of hormones and chemicals in the brain and body.
While this response is natural and vital to our survival, chronic stress and repeated fight-or-flight responses can lead to many issues including: anxiety, insomnia, fatigue, illness, weight gain or weight loss, and inflammation.
One of the key players in the stress response is cortisol – often referred to as the “stress hormone.”
Not only is cortisol released to help start the fight-or-flight response, but it also plays a role in stopping the stress response.
When cortisol is depleted through unrelenting stress, we begin to have problems turning off the stress response.
Cortisol also suppresses the immune system.
Whenever we are barraged with cortisol’s release over long periods of time we may experience illness.
This is why we often catch a cold when we are under periods of intense stress.
When cortisol is released for too long, it can also damage the hippocampus – leading to cognitive and memory issues.
It’s not just cortisol that can wreak havoc on our brains and bodies.
The constant release of norepinephrine and epinephrine (adrenaline) and the dramatic increase and subsequent lowering of our blood sugar levels also play a role in creating anxiety and health problems.
The fight-or-flight response alone isn’t the issue – it is when we respond in this way repeatedly that this constant release of hormones causes problems.
We can repeatedly trigger the fight-or-flight response for many reasons.
A few of the most common are:
- we might live in a dangerous or stressful environment
- we could be suffering from an underlying illness
- we could have past trauma or unresolved psychological issues
- we could have an overly sensitive amygdala
- we could have less of the calming neurotransmitters such as GABA or serotonin
Regardless of the reasons for our overactive fight-or-flight responses – once we get caught up in triggering this response regularly we begin to deplete cortisol, making it harder to turn it off.
As it becomes harder to turn off, we prolong the response and set up a cycle of stress.
Just as significant (and important to understanding how anxiety works) – is the fact that once we begin to repeat thoughts, actions or responses it becomes significantly easier to have these thoughts or responses.
We create “anxiety pathways,” setting ourselves up for worry, anxiety and panic on a regular basis.
Repetition: Creating Anxiety Pathways in the Brain
If you’ve been dealing with anxiety for any length of time, you've probably come to realize that once you get into the habit of worrying, catastrophizing, or responding to experiences with the fight-or-flight response – it becomes easier and easier to repeat these patterns and harder and harder to break away from them.
This habit of worry and anxiety response is due to physiological reasons just as much as any psychological ones.
This is because the repetition of an action or thought increases the likelihood and ease of performing the action (such as having a panic attack) or thinking the worrying thought (such as “the world is unsafe”).
In neuroscience we understand that the brain recognizes repetition as an indicator of significance – therefore the brain literally changes its structure to help make that repetitive thought or action easier to perform.
Repetition of anxiety-producing actions, thoughts, worries or mental images actually strengthens that particular mental or physical action.
The brain supports the neurons responsible for that particular action.
Through repetition, the neurons begin to fire more efficiently, making it easier to keep performing the action.
By constantly repeating anxiety-producing thoughts or actions, we have essentially created anxiety pathways in the brain.
Easy to get on, hard to get off.
Using panic attacks as an example; once we begin having panic attacks repeatedly, it becomes easier and easier to have panic attacks.
Activation of the panic response (the fight-or-flight response) occurs much more easily.
Techniques and therapies focused on reducing the duration and frequency of panic attacks can slow the activation of the response and make it harder to begin in the first place.
Therapies for worry and dealing with anxiety-producing thoughts – focus on eliminating repetitive thoughts and actions.
Cognitive Behavioral Therapy (CBT) is a perfect example of this.
CBT puts a strong focus on keeping track of our cognitive processes (what we think about, focus on, worry about, how we interpret things, etc.) and then works to change the thoughts and processes that don’t serve us.
Whether we are dealing with worry, panic attacks, or any type of anxiety – by reducing the duration and frequency of particular actions, we will (over time) undo the pathway our brains created.
Allowing us to step off the path of anxiety.
Although it may sound like common sense, it may be somewhat strange to hear the following, which best sums it up: the less we worry or have anxiety-producing thoughts or actions, the easier it is not to worry or having anxiety-producing thoughts.
The more we fall into the habit of worry, anxiety and panic through repetition – the harder it is NOT to have these thoughts or responses.
Putting It All Together
If you’ve made it with me this far (and it's been a long journey I know), you hopefully have a better understanding of how anxiety works and the processes involved.
We’ve discussed the limbic system and the amygdala in particular and its role in trauma – labeling potential threat and starting the fight-or-flight response.
We’ve talked about the cortex, where our thoughts and mental images are formed and which can often lead to anxiety or make our anxiety worse by activating the amygdala.
We went over the different neurotransmitters and their role in anxiety, fear, tension and panic.
We discussed the sympathetic and parasympathetic nervous systems and how the fight-or-flight response (stress response) works.
And we talked about repetition and falling into the habit of anxiety.
All of the information we've gone over is part of the anxiety process.
But let us bring it down to real-world concrete examples to help clarify the entire process.
By seeing how these different parts function in a real-life example, we can better understand how anxiety works in everyday life.
Let’s take the scenario we used way back at the beginning of this article:
You plan on doing some shopping so you hop in your car and head to the mall. As you approach the parking lot, you begin feeling anxious. By the time you park your car, your heart is beating and your stomach is in knots. Your mind begins to replay images of the last time you were here and how anxious you felt. You think “It will happen again,” “Why am I so afraid?” “What if I have to leave?” “What if everyone notices me freaking out?” By the time you walk from your car to the front door of the mall you’re on the verge of a panic attack; thoughts racing, heart pounding, stomach churning and your hands clammy as you reach for the door.
How do the different systems and processes we discussed play out in this example? Let’s break it down one piece at a time.
You plan on doing some shopping so you hop in your car and head to the mall. As you approach the parking lot, you begin feeling anxious.
The mall (public place/social engagement) seems to be an amygdala trigger (the amygdala has labeled it as a threat), given the fact you are already anxious by the time you reach the parking lot. You could have also had anxiety-producing thoughts on the drive over and not realized it (cortex) or seeing the mall itself could have triggered the amygdala and your anxiety.
By the time you park your car, your heart is beating and your stomach is in knots. Your mind begins to replay images of the last time you were here and how anxious you felt.
The fight-or-flight response has already begun based on your physical symptoms. The amygdala has been triggered by your memory of the last time you were here (remember the amygdala focuses on strong emotions related to safety or potential threat). The sympathetic nervous system has been activated by the amygdala; heart rate increased, digestion slowed and blood moved away from the gut to the muscles and extremities.
You think “It will happen again,” “Why am I so afraid?” “What if I have to leave?” “What if everyone notices me freaking out?”
The cortex makes matters worse with fearful thoughts, making the fight-or-flight response more intense. You worry about the sensations you are experiencing, possibly triggering a panic attack.
By the time you walk from your car to the front door you’re on the verge of a panic attack; thoughts racing, heart pounding, stomach churning and your hands clammy as you reach for the door.
The fight-or-flight response is in full swing at this point. If you continue to worry and fear your sensations you may have a panic attack. Otherwise, it will pass as the parasympathetic nervous system calms the response and returns you to homeostasis. It always passes no matter how bad it seems.
What about neurotransmitters?
Neurotransmitters play a significant role not only during anxiety but before and after.
Neurotransmitters play a part in the duration and intensity of our anxiety, how we respond and whether we go down the path of anxiety and panic in the first place.
We are not robots governed solely my transmitters in our brains – but neurotransmitters play a strong role in whether we tend to focus on negative thoughts and scenarios or healthy affirming ones (serotonin), the intensity of our anxiety (dopamine), the overactivity or calm of our minds (GABA) and whether we over-respond to small stresses (norepinephrine).
Where does repetition fit into this scenario?
Through repetition and repeating the behavior of worry, anxiety and panic whenever we approach the mall – we make it much easier to become anxious and panic whenever we are in the same situation.
In the example, I mentioned the memory of being anxious the last time you were at the mall, which kicked off the anxiety and panic.
Repetition is already beginning to reinforce the panic response being triggered by the mall.
If the repetition continues, we will begin to automatically panic whenever we go to the mall.
This is something we would need to break ourselves away from.
Final Thoughts
I discovered much of this information after nearly a decade of dealing with anxiety and panic attacks.
While learning how anxiety works didn’t cure my anxiety, it helped me to put things into perspective and understand what was happening when I was anxious or in the throes of panic.
Learning this information also helped to reduce my fear around the physical symptoms of anxiety and the fight-or-flight response.
My pounding heart wasn’t a heart attack – it was simply an increased heart rate and increased blood flow.
The dizziness I felt didn’t mean I was about to pass out – it was simply the release of different brain chemicals and a change in blood sugar levels.
Both were normal parts of the fight-or-flight response.
This information also helped me to see how I was creating a lot of my own anxiety (being anxious about anxiety) and how I was making minor anxiety-producing situations much worse.
I have written this article to help you understand the processes behind anxiety so you can understand what is happening when you experience anxiety.
Hopefully, it will help to reduce your fears around anxiety and lead to a better understanding of the techniques and therapies you can use to handle the anxiety you are dealing with – as it did for me.
Related Articles You May Find Helpful:
Related Resources
- The American Journal of Psychiatry: Using Neuroscience to Help Understand Fear and Anxiety
- NCBI: The Neurobiology of Anxiety Disorders
- The Journal of Neuroscience: Contributions of the Central Extended Amygdala to Fear and Anxiety
- NCBI: Amygdala Activity, Fear and Anxiety: Modulation by Stress
- Science Direct: Parasympathetic Nervous System
- Harvard Health Publishing: Understanding the Stress Response
- NCBI: The Peripheal Sympathetic Nervous System – It's Role in Normal and Pathologic Anxiety
- Medscape: What are the CNS Mediators of Anxiety Disorder Symptoms?
- NCBI: The Neurocircuitry of Fear, Stress and Anxiety Disorders
- Healthline: Chemical Imbalance in the Brain: What You Should Know
- NCBI: How the Prefrontal Cortex Modulates the Subcortical Fear Response
- Science Daily: Individuals with Social Phobia have too much Serotonin- not too little
- Psychology Today: Panic as Fight-or-Flight
- NIH.gov: Stress System Malfunction Could Lead to Serious Disease
- JAMA Psychiatry: Sympathetic Activity in Patients with Panic Disorder
- IJPSR: Role of Different Neurotransmitters in Anxiety
- NCBI: The Neurobiological Mechanisms of GAD and Chronic Stress
