Specific phobias have a one-year prevalence of 8.7% in the USA with 21.9% of the cases being severe, 30.0% moderate and 48.1% mild. The usual age of onset is childhood to adolescence. Women are twice as likely to suffer from specific phobias as men.

Evolutionary psychology argues that infants or children develop specific phobias to things that could possibly harm them, so their phobias alert them to the danger.

The most common co-occurring disorder for children with a specific phobia is another anxiety disorder. Although comorbidity is frequent for children with specific phobias, it tends to be lower than for other anxiety disorders.

Onset is typically between 7 and 9 years of age. Specific phobias can occur at any age but seem to peak between 10 and 13 years of age.

Social anxiety disorder is known to appear at an early age in most cases. Fifty percent of those who develop this disorder have developed it by the age of 11, and 80% have developed it by age 20. This early age of onset may lead to people with social anxiety disorder being particularly vulnerable to depressive illnesses, drug abuse and other psychological conflicts.

When prevalence estimates were based on the examination of psychiatric clinic samples, social anxiety disorder was thought to be a relatively rare disorder. The opposite was found to be true; social anxiety was common, but many were afraid to seek psychiatric help, leading to an underrecognition of the problem.

The National Comorbidity Survey of over 8,000 American correspondents in 1994 revealed 12-month and lifetime prevalence rates of 7.9 percent and 13.3 percent, respectively; this makes it the third most prevalent psychiatric disorder after depression and alcohol dependence, and the most common of the anxiety disorders. According to U.S. epidemiological data from the National Institute of Mental Health, social phobia affects 15 million adult Americans in any given year. Estimates vary within 2 percent and 7 percent of the U.S. adult population.

The mean onset of social phobia is 10 to 13 years. Onset after age 25 is rare and is typically preceded by panic disorder or major depression. Social anxiety disorder occurs more often in females than males. The prevalence of social phobia appears to be increasing among white, married, and well-educated individuals. As a group, those with generalized social phobia are less likely to graduate from high school and are more likely to rely on government financial assistance or have poverty-level salaries. Surveys carried out in 2002 show the youth of England, Scotland, and Wales have a prevalence rate of 0.4 percent, 1.8 percent, and 0.6 percent, respectively. In Canada, the prevalence of self-reported social anxiety for Nova Scotians older than 14 years was 4.2 percent in June 2004 with women (4.6 percent) reporting more than men (3.8 percent). In Australia, social phobia is the 8th and 5th leading disease or illness for males and females between 15–24 years of age as of 2003. Because of the difficulty in separating social phobia from poor social skills or shyness, some studies have a large range of prevalence. The table also shows higher prevalence in Sweden.

Agoraphobia occurs about twice as commonly among women as it does in men. The gender difference may be attributable to several factors: sociocultural traditions that encourage, or permit, the greater expression of avoidance coping strategies by women (including dependent and helpless behaviors), women perhaps being more likely to seek help and therefore be diagnosed, and men being more likely to abuse alcohol in reaction to anxiety and be diagnosed as an alcoholic. Research has not yet produced a single clear explanation for the gender difference in agoraphobia.

Panic disorder with or without agoraphobia affects roughly 5.1% of Americans, and about 1/3 of this population with panic disorder have comorbid agoraphobia. It is uncommon to have agoraphobia without panic attacks, with only 0.17% of people with agorophobia not presenting panic disorders as well.

It has been shown that there is a two to threefold greater risk of having social phobia if a first-degree relative also has the disorder. This could be due to genetics and/or due to children acquiring social fears and avoidance through processes of observational learning or parental psychosocial education. Studies of identical twins brought up (via adoption) in different families have indicated that, if one twin developed social anxiety disorder, then the other was between 30 percent and 50 percent more likely than average to also develop the disorder. To some extent this 'heritability' may not be specific – for example, studies have found that if a parent has any kind of anxiety disorder or clinical depression, then a child is somewhat more likely to develop an anxiety disorder or social phobia. Studies suggest that parents of those with social anxiety disorder tend to be more socially isolated themselves (Bruch and Heimberg, 1994; Caster et al., 1999), and shyness in adoptive parents is significantly correlated with shyness in adopted children (Daniels and Plomin, 1985).

Growing up with overprotective and hypercritical parents has also been associated with social anxiety disorder. Adolescents who were rated as having an insecure (anxious-ambivalent) attachment with their mother as infants were twice as likely to develop anxiety disorders by late adolescence, including social phobia.

A related line of research has investigated 'behavioural inhibition' in infants – early signs of an inhibited and introspective or fearful nature. Studies have shown that around 10–15 percent of individuals show this early temperament, which appears to be partly due to genetics. Some continue to show this trait into adolescence and adulthood, and appear to be more likely to develop social anxiety disorder.

Chronic use of tranquilizers and sleeping pills such as benzodiazepines has been linked to onset of agoraphobia. In 10 patients who had developed agoraphobia during benzodiazepine dependence, symptoms abated within the first year of assisted withdrawal. Similarly, alcohol use disorders are associated with panic with or without agoraphobia; this association may be due to the long-term effects of alcohol misuse causing a distortion in brain chemistry.

Tobacco smoking has also been associated with the development and emergence of agoraphobia, often with panic disorder; it is uncertain how tobacco smoking results in anxiety-panic with or without agoraphobia symptoms, but the direct effects of nicotine dependence or the effects of tobacco smoke on breathing have been suggested as possible causes. Self-medication or a combination of factors may also explain the association between tobacco smoking and agoraphobia and panic.

Discomfort from separations in children from ages 8 to 14 months is normal. Children oftentimes get nervous or afraid of unfamiliar people and places but if the behavior still occurs after the age of 6 and if it lasts longer than four weeks, the child might have Separation Anxiety Disorder.

About 4% of children have the disorder. Separation Anxiety Disorder is very treatable especially when caught early on with medication and behavioral therapies. Helping children with separation anxiety to identify the circumstances that elicit their anxiety (upcoming separation events) is important. A child's ability to tolerate separations should gradually increase over time when he or she is gradually exposed to the feared events. Encouraging a child with separation anxiety disorder to feel competent and empowered, as well as to discuss feelings associated with anxiety-provoking events promotes recovery.

Children with separation anxiety disorder often respond negatively to perceived anxiety in their caretakers, in that parents and caregivers who also have anxiety disorders may unwittingly confirm a child's unrealistic fears that something terrible may happen if they are separated from each other. Thus, it is critical that parents and caretakers become aware of their own feelings and communicate a sense of safety and confidence about separation.

Several studies aim to understand the long-term mental health consequences of SAD. SAD contributed to vulnerability and acted as a strong risk factor for developing other mental disorders in people aged 19–30. Specifically disorders including panic disorder and depressive disorders were more likely to occur. Other sources also support the increased likelihood of displaying either of the two psychopathologies with previous history of childhood SAD.

GAD runs in families and is six times more common in the children of someone with the condition.

While anxiety arose as an adaptation, in modern times it is almost always thought of negatively in the context of anxiety disorders. People with these disorders have highly sensitive systems; hence, their systems tend to overreact to seemingly harmless stimuli. Sometimes anxiety disorders occur in those who have had traumatic youths, demonstrating an increased prevalence of anxiety when it appears a child will have a difficult future. In these cases, the disorder arises as a way to predict that the individual’s environment will continue to pose threats.

At a low level, anxiety is not a bad thing. In fact, the hormonal response to anxiety has evolved as a benefit, as it helps humans react to dangers. Researchers in evolutionary medicine believe this adaptation allows humans to realize there is a potential threat and to act accordingly in order to ensure greatest possibility of protection. It has actually been shown that those with low levels of anxiety have a greater risk of death than those with average levels. This is because the absence of fear can lead to injury or death. Additionally, patients with both anxiety and depression were found to have lower morbidity than those with depression alone. The functional significance of the symptoms associated with anxiety includes: greater alertness, quicker preparation for action, and reduced probability of missing threats. In the wild, vulnerable individuals, for example those who are hurt or pregnant, have a lower threshold for anxiety response, making them more alert. This demonstrates a lengthy evolutionary history of the anxiety response.

Phobias are a common form of anxiety disorders and distributions are heterogeneous by age and gender. An American study by the National Institute of Mental Health (NIMH) found that between 8.7 percent and 18.1 percent of Americans suffer from phobias, making it the most common mental illness among women in all age groups and the second most common illness among men older than 25. Between 4 percent and 10 percent of all children experience specific phobias during their lives, and social phobias occur in one percent to three percent of children and adolescents.

A Swedish study found that females have a higher incidence than males (26.5 percent for females and 12.4 percent for males). Among adults, 21.2 percent of women and 10.9 percent of men have a single specific phobia, while multiple phobias occur in 5.4 percent of females and 1.5 percent of males. Women are nearly four times as likely as men to have a fear of animals (12.1 percent in women and 3.3 percent in men) — a higher dimorphic than with all specific or generalized phobias or social phobias. Social phobias are more common in girls than in boys, while situational phobia occurs in 17.4 percent of women and 8.5 percent of men.

According to Child and Adolescent Mental Health, approximately 5 percent of children suffer from specific phobias and 15 percent seek treatment for anxiety-related problems. In recent years the number of children with clinically diagnosed phobias has gradually increased. Researchers are finding that the majority of these diagnoses come anxiety related phobias or society phobias.

Specific phobias are more prevalent in girls than in boys. Likewise, specific phobias are also more prevalent in older children than younger.

Though some fears are inborn, the majority are learned. Phobias develop through negative experiences and through observation. One way children begin to develop fears is by witnessing or hearing about dangers. Ollendick proposes while some phobias may originate from a single traumatizing experience, others may be caused by simpler, or less dramatic, origins such as observing another child’s phobic reaction or through the exposure to media that introduces phobias.

- 2% of parents linked their child’s phobia to a [direct conditioning episode]

- 26% of parents linked their child’s phobia to a [vicarious conditioning episodes]

- 56% of parents linked their child’s phobia to their child’s very first contact with water

- 16% of parents could not directly link their child’s phobia

In addition to asking about the origins of a child’s fear, the questionnaire asked if parents believed that “information associated with adverse consequences was the most influential factor in the development of their child’s phobia.” The results were as followed:

- 0% of parents though it was the most influential factor

- 14% of parents though it was somewhat influential

- 86% of parents though it had little to no influence

Mental health professionals often distinguish between generalized social phobia and specific social phobia. People with generalized social phobia have great distress in a wide range of social situations. Those with specific social phobia may experience anxiety only in a few situations. The term "specific social phobia" may also refer to specific forms of non-clinical social anxiety.

The most common symptoms of specific social phobia are glossophobia, the fear of public speaking and

the fear of performance, known as stage fright. Other examples of specific social phobia include fears of intimacy or sexual encounters, internet phobia, using public restrooms (paruresis), attending social gatherings, and dealing with authority figures.

Specific social phobia may be classified into performance fears and interaction fears, i.e., fears of acting in a social setting and interacting with other people, respectively. The cause of social phobia is not definite.

Symptoms of social phobia can occur in late adolescence when youths highly value the impressions they give off to their peers. Clinical experience of the prognosis of social phobia shows that it can prolong for many years but that it improves by mid life.

BII phobia is one of the more common psychiatric disorders, affecting about 3 to 4% of the general population, and in about 80% of the BII phobia cases, the patient experiences syncope or presyncope. After a random survey was completed in Aligarh, India, with 1648 male and 1613 female, it was found that a significantly higher percentage of females compared to males had BII phobia; 23.36% of females were diagnosed with BII phobia while only 11.19% of males were diagnosed. Females also fainted more often than males, at 64.09% compared to a male rate of 39.4%.

Furthermore, only 5.3% of BII phobia patients reported to have visited the hospital once or twice for consultation about BII phobia, however, without engaging in any kind of treatment.

Another study, involving participants from all 50 states and the District of Columbia, ages 65 years and older, found that a total of 386 participants disclosed having BII Phobia throughout their whole lifetime, 90% of those cases consisted of patients dealing with BII Phobia as well as other lifetime fears.

There is a strong agreement in the scientific community that there is no specific cause of emetophobia. Some emetophobics report a traumatic experience with vomiting, almost always in childhood, but many do not. Some suggest that sufferers are victims of childhood abuse – sexual or physical. While this is occasionally true, it seems to be no more prevalent than in the general population. (Christie, 2004) Some experts believe that emetophobia may be linked to worries about lack of control. Many people try to control themselves and their environment in every possible way, but vomiting is difficult or impossible to control.

There are many factors that can cause a legitimate case of emetophobia. It can affect the minds of young children, but emetophobia can also affect a person at any age. While some emetophobics are indeed severely mentally ill, many are not and have been diagnosed as such and treated inappropriately.

Dr. Angela L. Davidson "et al". conducted an experiment where it was concluded through various surveys that people suffering from emetophobia are more likely to have an internal locus of control pertaining to their everyday life as well as health-related matters. A locus of control is an individual's perception of where control comes from. Having an internal locus of control means that an individual perceives that they have their own control over a situation whereas an external locus of control means that an individual perceives that some things are out of their control.

She explains how this phobia is created through the locus of control by stating, "Thus far, it seems reasonable to stipulate that individuals with a vomiting phobia deem events as being within their control and may therefore find it difficult to relinquish this control during the act of vomiting, thus inducing a phobia."

In an internet survey conducted by Dr. Joshua D. Lipsitz et al. given to emetophobic people, respondents gave many different reasons as to why they became emetophobic. Among some of the causes listed were severe bouts of vomiting as children and being firsthand witnesses to severe vomiting in others due to illness, pregnancy, or alcoholism.

A phobia is a type of anxiety disorder, defined by a persistent fear of an object or situation. The phobia typically results in a rapid onset of fear and is present for more than six months. The affected person will go to great lengths to avoid the situation or object, typically to a degree greater than the actual danger posed. If the feared object or situation cannot be avoided, the affected person will have significant distress. With blood or injury phobia, fainting may occur. Agoraphobia is often associated with panic attacks. Usually a person has phobias to a number of objects or situations.

Phobias can be divided into specific phobias, social phobia, and agoraphobia. Types of specific phobias include those to certain animals, natural environment situations, blood or injury, and specific situations. The most common are fear of spiders, fear of snakes, and fear of heights. Occasionally they are triggered by a negative experience with the object or situation. Social phobia is when the situation is feared as the person is worried about others judging them. Agoraphobia is when fear of a situation occurs because it is felt that escape would not be possible.

Specific phobias should be treated with exposure therapy where the person is introduced to the situation or object in question until the fear resolves. Medications are not useful in this type of phobia. Social phobia and agoraphobia are often treated with some combination of counselling and medication. Medications used include antidepressants, benzodiazepines, or beta-blockers.

Specific phobias affect about 6–8% of people in the Western world and 2–4% of people in Asia, Africa, and Latin America in a given year. Social phobia affects about 7% of people in the United States and 0.5–2.5% of people in the rest of the world. Agoraphobia affects about 1.7% of people. Women are affected about twice as often as men. Typically onset is around the age of 10 to 17. Rates become lower as people get older. People with phobias are at a higher risk of suicide.

Typically, this disease is presaged by a childhood history of social inhibition and shyness. It is possible that it could result from a humiliating traumatic experience, or it could emerge from a lifelong onset of the illness that only comes to the surface after time.

Clinical data indicates that more males have the condition than females, despite the fact that females scored higher on a social phobia scale than men, and report higher scores on proclivity towards feelings of embarrassment. This differs from Western society where the prevalence of females with social phobias is to some extent greater than that of males. The lifetime prevalence of the disorder falls anywhere between 3% and 13% with changes in severity occurring throughout one's lifetime. It is estimated that about 17% of individuals with taijin kyofusho have fears of releasing foul body odor.

Panic disorder typically begins during early adulthood; roughly half of all people who have panic disorder develop the condition before age 24, especially those subjected to traumatic experiences. However, some sources say that the majority of young people affected for the first time are between the ages of 25 and 30. Women are twice as likely as men to develop panic disorder and it occurs more often in people with above average intelligence.

Panic disorder can continue for months or years, depending on how and when treatment is sought. If left untreated, it may worsen to the point where one's life is seriously affected by panic attacks and by attempts to avoid or conceal the condition. In fact, many people have had problems with personal relationships or employment while struggling to cope with panic disorder. Some people with panic disorder may conceal their condition because of the stigma of mental illness. In some individuals, symptoms may occur frequently for a period of months or years, then many years may pass without symptoms. In some cases, the symptoms persist at the same level indefinitely. There is also some evidence that many individuals (especially those who develop symptoms at an early age) may experience symptom cessation later in life (e.g. past age 50).

In 2000, the World Health Organization found prevalence and incidence rates for panic disorder to be very similar across the globe. Age-standardized prevalence per 100,000 ranged from 309 in Africa to 330 in East Asia for men and from 613 in Africa to 649 in North America, Oceania, and Europe for women.

Treatment of social phobia usually involves psychotherapy, medication, or both.

A specific phobia is any kind of anxiety disorder that amounts to an unreasonable or irrational fear related to exposure to specific objects or situations. As a result, the affected person tends to avoid contact with the objects or situations and, in severe cases, any mention or depiction of them. The fear can, in fact, be disabling to their daily lives.

The fear or anxiety may be triggered both by the presence and the anticipation of the specific object or situation. A person who encounters that of which they are phobic will often show signs of fear or express discomfort. In some cases, it can result in a panic attack. In most adults, the person may logically know the fear is unreasonable but still find it difficult to control the anxiety. Thus, this condition may significantly impair the person's functioning and even physical health.

Specific phobia affects up to 12% of people at some point in their life.

Many people report stress-induced speech disorders which are only present during public speech. Some individuals with glossophobia have been able to dance, perform in public, or even to speak (such as in a play), or sing if they cannot see the audience, or if they feel that they are presenting a character or stage persona other than themselves. Being able to blend in a group (as in a choir or band) has been reported to also alleviate some anxiety caused by glossophobia.

It has been estimated that 75% of all people experience some degree of anxiety/nervousness when it comes to public speaking. In fact, surveys have shown that most people fear public speaking more than they fear death. If untreated, public speaking anxiety can lead to serious detrimental effects on one's quality of life, career goals and other areas. For example, educational goals requiring public speaking might be left unaccomplished. However, not all persons with public speaking anxiety are necessarily unable to achieve work goals, though this disorder becomes problematic when it prevents an individual from attaining or pursuing a goal they might otherwise have - were it not for their anxiety.

A recent study conducted by Garcia-Lopez, Diez-Bedmar, and Almansa-Moreno (2013) has reported that previously trained students could act as trainers to other students and help them to improve their public speaking skills.

The cause of BII phobia is not well known. Some studies show that specific genes make one more vulnerable to the phobia. Other studies suggest that just like any other phobia, BII phobia could be caused by a traumatic experience (Chapman). It has been proved that social stress amplifies BII symptoms, however, it is not a main cause.

Phobophobia is the fear of phobia(s) and, more specifically, of the internal sensations associated with that phobia and anxiety, which binds it closely to other anxiety disorders, especially with generalized anxiety disorders (free floating fears) and panic attacks. It is a condition in which anxiety disorders are maintained in an extended way, which combined with the psychological fear generated by phobophobia of encountering the feared phobia would ultimately lead to the intensifying of the effects of the feared phobia that the patient might have developed, such as agoraphobia, and specially with it, and making them susceptible to having an extreme fear of panicking. Phobophobia comes in between the stress the patient might be experiencing and the phobia that the patient has developed as well as the effects on his life, or in other words, it is a bridge between anxiety/panic the patient might be experiencing and the type of phobia he/she fears, creating an intense and extreme predisposition to the feared phobia. Nevertheless, phobophobia is not necessarily developed as part of other phobias, but can be an important factor for maintaining them.

Phobophobia differentiates itself from other kind of phobias by the fact that there is no environmental stimulus per se, but rather internal dreadful sensations similar to psychological symptoms of panic attacks. The psychological state of the mind creates an anxious response that has itself a conditioned stimuli leading to further anxiety, resulting in a vicious cycle. Phobophobia is a fear experienced before actually experiencing the fear of the feared phobias its somatic sensations that precede it, which is preceded by generalized anxiety disorders and can generate panic attacks. Like all the phobias, the patients avoids the feared phobia in order to avoid the fear of it.

The telephone is important for both contacting others and accessing important and useful services. As a result, this phobia causes a great deal of stress and impacts people's personal lives, work lives and social lives. Sufferers avoid many activities, such as scheduling events or clarifying information. Strain is created in the workplace because use of phones may play a crucial role within a career.

There are three major categories of driving phobia, distinguished by their onset.

The first and most common cause of a fear of driving is traffic accidents. These situations cause PTSD driving phobia, where the fear develops in response to a traumatic event. Usually, situations like these trigger a fear of driving in only specific situations related to the original cause, though it also can trigger a fear of driving entirely.

The second most common form is driving phobia as a specific phobia. Because driving does involve some danger and the possibility of a collision, there does exist some fear or caution in many rational people. However, for some the fear of crashing, losing control over the car, being criticized or being in a dangerous situation will cause panic. It is classified as a phobia when the anxiety does not rationally reflect the amount of danger.

The least common category is an extension of agoraphobia, the anxiety of having a panic attack while being in crowds or public places. One manifestation of agoraphobia is the inability to travel long distances away from home. When driving, an agoraphobe may feel that he is putting himself into a fearful situation, and driving phobia may develop.