Fear: Definition, Symptoms, Traits, Causes, Treatment (2023)

By Olivia Guy-Evans, published Jan 04, 2022

by Saul Mcleod, PhD

Fear is a natural and primitive emotion that can be experienced by everyone to some degree. It alerts us to the presence of dangers, whether they be real dangers or imagined.

People may experience fear when in situations such as walking home alone at night, when faced with animals they perceive as dangerous, or when about to skydive out of a plane.

Fear can also be attributed to feelings of stress and anxiety. It may also contribute to some feelings of disgust, as according to a study investigating those who feared or did not fear snakes, those who experienced this fear reported high feelings of disgust as well as fear (Rádlová et al., 2020).

Biochemical Reaction

Fear is a normal response to many situations and is composed of two primary reactions: biochemical and emotional reactions.The biochemical reaction to fear causes our bodies to respond to perceived threats in the environment.

This produces automatic physical reactions such as sweating, increased heart rate, and dilated pupils. The purpose of these bodily reactions is to prepare the body to either combat the threat or to run away from it - this is called the ‘fight or flight’ response.

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In response to a threat the sympathetic nervous system, part of the autonomic nervous system, is activated by the sudden release of hormones.

The sympathetic nervous system then stimulates the adrenal glands to trigger the release of hormones, specifically epinephrine (adrenaline) and norepinephrine (noradrenaline), which results in the physical reactions.

Emotional Response

The emotional response to fear, however, is personalized to the individual. Since the biology of fear involves some of the same chemical responses to positive emotions such as excitement and happiness, people can experience either positive or negative emotions to fear.

For instance, some people may find enjoyment in riding extreme rollercoasters whilst others may have a negative reaction and will avoid these at all costs.

Although the biochemical reaction for fear may be the same, some people will experience the intensity of fearful situations differently than others.

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Symptoms and diagnosis

People can experience fear differently, but some of the common physical and emotional symptoms are:

  • Sweating

  • Rapid heart rate

  • Nausea

  • Chest pain

  • Dry mouth

  • Upset stomach

  • Chills

  • Shortness of breath

  • Trembling

  • Feeling overwhelmed

  • Feeling upset

  • Feeling out of control

  • A sense of impending death

  • Dread

For a condition associated with fear and anxiety to be diagnosed, the symptoms must be persistent, interfere with some part of normal functioning, and cannot be better explained by another condition.

If feelings of fear become persistent and excessive, this could be diagnosed as an anxiety disorder depending on the symptoms being experienced.

Common disorders which are associated with fear are: phobias, generalized anxiety disorder, social anxiety disorder, and panic disorder.

Is fear useful?

In a lot of situations, fear is normal and healthy in that it can keep us from entering harmful situations and can help us decide when to get out from these situations.

The immediate threat of danger and the physical responses that come with it can help focus our attention and mobilize us to cope with the danger. Fear may also help us to react to danger without having to consciously think about it.

For example, if a car is coming towards us, fear can make us jump out of the way and thus save our lives. Also, if humans have the capacity to notice fear in others since we recognize it in ourselves, we can offer compassion and reassurance to others to help them cope.

In contrast, extreme levels of fear could result in the development of mental health conditions such as phobias or other anxiety conditions. A phobia is an intense and persistent fear or something, an event, or a situation.

Phobias twist the normal fear response into something difficult or impossible to control and can be detrimental to people’s lives. Likewise, other anxiety conditions such as generalized anxiety disorder and social anxiety disorder involve intense worry or fear of many things and social situations respectively.

The biochemical and emotional response to fear can be so extreme that it can interfere in people’s lives negatively. If fear gets to extreme levels such as in those experiencing anxiety disorders, it can keep us feeling trapped, preventing us from doing things we want to do.

Types of Fear


Phobias may be diagnosed when certain situations, events, or objects create a strong, irrational fear. Some symptoms of phobias include:

  • A sensation of uncontrollable anxiety when exposed to the source of the fear.

  • The feeling that the source of the fear needs to be avoided at all costs.

  • Not being able to function properly when exposed to the fear.

  • They may acknowledge that the fear is irrational and exaggerated combined with the inability to control feelings of fear.

There are different types of phobias that can be diagnosed: specific phobias, social phobias, and agoraphobia. Specific phobias are intense, irrational fears of a specific trigger.

Some common specific phobias are spiders and snakes. Social phobia is a profound fear of public humiliation or being judged negatively by others in social situations.

Agoraphobia is an intense fear of situations from which it would be difficult to escape if a person were to experience extreme panic. This could be a fear of open spaces as well as confined spaces.

Specific phobias are known as simple phobias since they can usually be linked to an identifiable cause and are unlikely to affect daily living as the person can simply avoid the trigger.

For instance, if someone has a phobia of heights, they are not likely to experience this fear day-to-day, only in situations where they may have to face their fear.

Social phobia and agoraphobia, however, are known as complex phobias since their triggers are less easily recognisable or avoidable and the individual is more likely to experience the associated fear more frequently than those with a specific phobia.

Generalized anxiety disorder (GAD)

Those who experience GAD typically have chronic and exaggerated worries about everyday life and worry about multiple things. They may be fearful about their health, finances, and safety to the point where it can become exhausting.

People with GAD tend to experience a lot of the physical symptoms associated with fear but more often and for more reasons.

Social anxiety disorder

Also known as social phobia, those with social anxiety disorder have an intense fear of social situations, often driven by irrational fears of humiliation.

If faced with a social situation, it is common that someone with social anxiety will experience physical symptoms such as sweating, blushing, rapid heart rate, and trembling.

They may feel these sensations before, during, and after a social situation alongside thoughts such as worries of being judged, making a mistake, or drawing unwanted attention to themselves.

Panic disorder

Panic disorder is characterized as experiencing panic attacks, which are sudden and intense feelings of terror.

These feelings could sometimes occur without warning and are associated with powerful physical symptoms such as chest pain, feeling short of breath, fast heart rate, and trembling.

Panic attacks can be so intense that the individual cannot function normally whilst experiencing one.

Causes of fear

Intense fears such as specific phobias usually develop in childhood and in some cases can be pinpointed to an exact moment.

In some cases, specific phobias can be the result of an early traumatic experience with the feared object, event, or situation, such as a phobia of bicycles being caused by a traumatic incident of falling off a bike as a child.

Phobias that start in childhood could also be caused by witnessing the phobia of a family member and developing the same phobia. For instance, if a parent has a phobia of spiders, the child may learn to also have a phobia of spiders.

Evolutionary theory of fear

Seligman (1971) applied his preparedness hypothesis theory to explain why humans fear. The preparedness hypothesis is the belief that humans have a tendency to fear thing which were a source of danger to our ancestors.

Seligman proposed that the fears of individuals who are diagnosed with phobias reflect the evolutionary prepared learning to fear events and situation that have provided survival threats.

He argued these threats would be from an evolutionary rather than a contemporary perspective.This can be used to explain why phobias such as threatening animals, heights, closed spaces, and social evaluations are very common and appear to be innate fears.

Whilst contemporary fears such as bicycles, broken electrical equipment, and guns as less common as these would not have been survival threats to our ancestors.

The preparedness hypothesis suggests that humans can have innate responses to specific stimuli without any previous environment input.

This has been tested with scientists who have found that it was easier to train humans to fear snakes and spiders than friendly dogs of pillows for instance.

This was found to be especially true for very young children who have appeared to be fearful of snakes and spiders before encountering or hearing about them.

Fear conditioning

Pavlovian fear conditioning is a state of fear or anxiety that has been demonstrated in animals after repeated pairings of a threatening stimulus with a previously neutral stimulus using classical conditioning.

In experiments, the researchers would pair a neutral stimulus with an unpleasant stimulus – such as a loud noise or shock. After repeated pairing of these two stimuli, eventually the neutral stimulus on its own would elicit a state of fear.

This is another way in which intense fear could be caused. The fear expressed by the animals would be seen as essential for their survival in this instance.

This fear conditioning could be learnt in humans who suffer from posttraumatic stress disorder (PTSD). PTSD is defined as the exaggerated and unrelenting unconditioned responses to stimuli (e.g., crowds, flashes of light, or sounds) which are associated with trauma (e.g., death or injury).

PTSD can bring about feelings of intense fear when something specifically triggers it. Most of the time, the trigger will not be an actual threat to survival but is a conditioned stimuli for the individual.

This means they can experience intense feelings of fear at times when it is not appropriate.

The brain’s fear response

The primary brain region that is responsible for fear is the amygdala. The amygdala is a collection of nuclei in the limbic system, deep in the brain.

Fear: Definition, Symptoms, Traits, Causes, Treatment (3)

Some of the main nuclei in the amygdala are the lateral, basal, central lateral, and central medical nuclei. The lateral nucleus is the primary input nucleus which receives input from the thalamus and the cortex of the brain, which provides it with information about the sensory stimuli that is being experienced.

The primary output nuclei of the amygdala is the central medial nucleus which projects to different structures such as the paraventricular nucleus of the hypothalamus which triggers the release of the stress hormone cortisol.

It also projects to the lateral hypothalamus to stimulate the autonomic nervous system, which results in the physiological symptoms associated with the fight or flight, or fear, response.

The amygdala is also thought to be the area of the brain responsible for fear conditioning. In rats it was found that an unconditioned stimulus such as a shock is picked up by the spinal cord, which sends this signal to the thalamus and the cortex which then both project to the lateral nucleus on the amygdala.

The synaptic inputs from the unconditioned stimulus are strong enough to excite the lateral amygdala neurons which results in activation of the neurons in the central medial nucleus and thus produces a fear response.Sensory information from a neutral stimulus (e.g., music) also reaches the thalamus and cortex but the inputs from this stimulus are not strong enough on their own to excite the lateral amygdala neurons, so the central amygdala neurons remain unstimulated and there is no fear response.

However, if the neutral stimulus (music) is paired with the unconditioned stimulus (shock), both can be encoded by neurons at the same time. This can strengthen the synapse between incoming neurons carrying information about the neutral stimulus and the lateral amygdala neurons.

Eventually, this synapse is strengthened enough to allow them to stimulate the lateral amygdala neurons on their own without the unconditioned stimulus. The lateral nucleus will then excite the central medial nucleus to produce the fear response.

The hippocampus, which plays a role in storing episodic memories can also interact with the amygdala and be involved in fear. The neurons from the hippocampus can project to the basal nucleus of the amygdala which can then stimulate the central medial nucleus.

Because it can do this, the hippocampus allows contextual-related memories to the fear. This could be why we can have fearful memories and why they are so strong.There are suggested to be sex differences in amygdala activation.

A study which used the brain imaging technique of functional magnetic resonance imaging (fMRI) found that when presented with happy facial expressions, there was greater activation in the right amygdala for males but not for females.

Both males and females showed greater left amygdala activation for fearful faces which provides support that the left may be more involved in negative affect (Killgore & Yurgelun-Todd, 2001).Other researchers have found that the volumes of brain regions involved in fear may be different in those who have experienced more trauma.

Using MRI on children who experienced trauma, there was found to be reduced hippocampal and increased amygdala volume with increasing levels of trauma exposure. Higher levels of exposure to violence were also found to be associated with increase amygdala activation.

Finally, increased functional connectivity between the amygdala and the brain stem were associated with higher levels of exposure to violence (Van Rooij, et al., 2020).

Treatment and management

Treatments for phobias can often be used for conditions associated with extreme fear. These usually involve repeated exposure to the feared situation until they become familiar, to slowly minimize the fear response.

This was demonstrated in studies with the rats who had been trained to have a conditioned feared response to a stimulus. The researchers would eventually stop pairing the unconditioned stimulus (such as a shock) with the now conditioned stimulus (such as music), they would only present the conditioned stimulus.

After repeated exposure to the conditioned stimulus the rats were able to eventually have neutral feelings toward it once realising that nothing bad was going to happen, so it became a neutral stimulus again.

Systematic desensitization

A common therapy for people with extreme fears is systematic desensitization. This involves gradually leading the individual through a series of exposure situations, commonly used for those with specific phobias.

For instance, if someone has a phobia of spiders the steps may go as follows:

  1. Talking to the therapist about spiders

  2. See pictures of spiders – this could start off as drawings and gradually getting more realistic until the patient can manage viewing a photo of one.

  3. The patient may be encouraged to watch video footage of a spider

  4. The patient could handle a toy spider

  5. Eventually the patient should get to a stage where they can face a real spider

The steps taken to complete the therapy may take a long time depending on how strong the fear is.

Once the individual feels comfortable at each step and the fear is diminishing can they move onto the next step until they gradually become desensitized to their fear.


Flooding is a type of exposure therapy that works on the idea that phobias are a learned behavior and so can be unlearnt.

This method involves exposing the individual with a vast amount of their fear for a prolonged period of time in a safe, controlled environment.

The individual may feel intense fear and anxiety for a while, but the idea is to get past the point of this overwhelming fear to a place where eventually the fear diminishes.

This is a way in which people can confront their fears and come to the realisation that after a while, nothing bad has happened and so this no longer becomes a fear.

Cognitive behavioral therapy (CBT)

CBT can be used to help tackle negative and unrealistic thoughts regarding the intense fear.

The individual can work with the therapist to work through their worries and try to form more realistic thoughts instead, challenge their fearful thoughts and learn coping strategies.

CBT is personalized to each person depending on their struggles. It allows people to learn different ways of understanding and reacting to the source of their fear and can help teach a person to control their own feelings and thoughts.


There are some medications that can be useful to aid with the symptoms of extreme fear:

Beta blockers – these work to reduce the physical symptoms of fear through lowering stress on the heart and blood vessels. These block the release of the stress hormones epinephrine and norepinephrine to prevent the fight or flight response from being triggered.

However, these can come with some side effects of insomnia, fatigue, and upset stomach.

Benzodiazepines – tranquilizers are a type of this medication. These help to reduce the symptoms of anxiety and have a sedative effect on the individual, meaning they slow down the body and brain function.

These medications can be taken when required but have been known to cause a dependency and can have withdrawal effects that could be life threatening.

Selective serotonin reuptake inhibitors (SSRIs) – these medications are a type of antidepressant and are commonly prescribed for phobias.

SSRIs affect serotonin levels in the brain and so can produce better moods in individuals. Side effects for these medications include nausea, sleep problems, and headaches.

Other coping methods

Relaxation techniques can be used to help people calm down. These can include meditation and breath retraining exercises to help treat the symptoms of fear, especially when faced with a fearful situation.

Progressive muscle relaxation is a technique where an individual purposely tenses a muscle group for a few seconds then releases it. The idea is that the release of the muscles should decrease any build up tension.

Working through all the muscle groups in this way can encourage the whole body to feel relaxed and reduce the fear response. Likewise, yoga can prove a useful method for reducing the fear response. The combination of physical postures, breathing exercises and meditation in yoga can all help people improve their management of anxiety disorders and fear.

Finally, exercise, specifically aerobic exercise can have a positive effect on stress and anxiety and may decrease the fear response symptoms.

Do you or a loved one need mental health help?


Contact the National Suicide Prevention Lifeline for support and assistance from a trained counselor. If you or a loved one are in immediate danger: https://suicidepreventionlifeline.org/



Contact the Samaritans for support and assistance from a trained counselor: https://www.samaritans.org/; email [emailprotected].

Availiale 24 hours day, 365 days a year (this number is FREE to call):


Rethink Mental Illness: rethink.org

0300 5000 927

About the Author

Olivia Guy-Evans obtained her undergraduate degree in Educational Psychology at Edge Hill University in 2015. She then received her master’s degree in Psychology of Education from the University of Bristol in 2019. Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years.

Fact Checking

Simply Psychology content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication.

How to reference this article:

How to reference this article:

Guy-Evans, O. (2022, Jan 04). What is fear. Simply Psychology. www.simplypsychology.org/what-is-fear.html

APA Style References

Brazier, Y. (2020, November 26). Everything you need to know about phobias. Medical News Today. https://www.medicalnewstoday.com/articles/249347

Fritscher, L. (2020, April 23. Differences Between Fear and Phobia Responses. Very Well Mind. https://www.verywellmind.com/fear-or-phobia-2671982

Fritscher, L. (2020, April 28). What Is Fear? Very Well Mind. https://www.verywellmind.com/the-psychology-of-fear-2671696#causes

Killgore, W. D., & Yurgelun-Todd, D. A. (2001). Sex differences in amygdala activation during the perception of facial affect.Neuroreport,12(11), 2543-2547.

Öhman, A. (2009). Of snakes and faces: An evolutionary perspective on the psychology of fear.Scandinavian journal of psychology,50(6), 543-552.

Rádlová, S., Polák, J., Janovcová, M., Sedláčková, K., Peléšková, Š., Landová, E., & Frynta, D. (2020). Emotional reaction to fear-and disgust-evoking snakes: sensitivity and propensity in snake-fearful respondents.Frontiers in psychology,11, 31.

Seligman, M. E. (1971). Phobias and preparedness.Behavior therapy,2(3), 307-320.

Steimer, T. (2002). The biology of fear-and anxiety-related behaviors.Dialogues in clinical neuroscience,4(3), 231.

van Rooij, S. J., Smith, R. D., Stenson, A. F., Ely, T. D., Yang, X., Tottenham, N., Stevens, J. S. & Jovanovic, T. (2020). Increased activation of the fear neurocircuitry in children exposed to violence.Depression and anxiety,37(4), 303-312.

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