# Social anxiety disorder

Social anxiety disorder (SAD), also known as social phobia, is an anxiety disorder characterized by sentiments of fear and anxiety in social situations, causing considerable distress and impairing ability to function in at least some aspects of daily life. These fears can be triggered by perceived or actual scrutiny from others. Individuals with social anxiety disorder fear negative evaluations from other people.
Physical symptoms often include excessive blushing, excessive sweating, trembling, palpitations, rapid heartbeat, muscle tension, shortness of breath, and nausea. Panic attacks can also occur under intense fear and discomfort. Some affected individuals may use alcohol or other drugs to reduce fears and inhibitions at social events. It is common for those with social phobia to self-medicate in this fashion, especially if they are undiagnosed, untreated, or both; this can lead to alcohol use disorder, eating disorders or other kinds of substance use disorders. SAD is sometimes referred to as an illness of lost opportunities where "individuals make major life choices to accommodate their illness". According to ICD-10 guidelines, the main diagnostic criteria of social phobia are fear of being the focus of attention, or fear of behaving in a way that will be embarrassing or humiliating, avoidance and anxiety symptoms. Standardized rating scales can be used to screen for social anxiety disorder and measure the severity of anxiety.
The first line of treatment for social anxiety disorder is cognitive behavioral therapy (CBT). CBT is effective in treating this disorder, whether delivered individually or in a group setting. The cognitive and behavioral components seek to change thought patterns and physical reactions to anxiety-inducing situations.
The attention given to social anxiety disorder has significantly increased since 1999 with the approval and marketing of drugs for its treatment. Prescribed medications include several classes of antidepressants: selective serotonin reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), and monoamine oxidase inhibitors (MAOIs). Other commonly used medications include beta blockers and benzodiazepines. Medications such as SSRIs are effective for social phobia, such as paroxetine.

## History

Literary descriptions of shyness can be traced back to the days of Hippocrates around 400 B.C. Hippocrates described someone who "through bashfulness, suspicion, and timorousness, will not be seen abroad; loves darkness as life and cannot endure the light or to sit in lightsome places; his hat still in his eyes, he will neither see, nor be seen by his good will. He dare not come in company for fear he should be misused, disgraced, overshoot himself in gesture or speeches, or be sick; he thinks every man observes him."
The first mention of the psychiatric term "social phobia" (phobie des situations sociales) was made in the early 1900s. Psychologists used the term "social neurosis" to describe extremely shy patients in the 1930s. After extensive work by Joseph Wolpe on systematic desensitization, research on phobias and their treatment grew. The idea that social phobia was a separate entity from other phobias came from the British psychiatrist Isaac Marks in the 1960s. This was accepted by the American Psychiatric Association and was first officially included in the third edition of the Diagnostic and Statistical Manual of Mental Disorders.
After a call to action by psychiatrist Michael Liebowitz and clinical psychologist Richard Heimberg, there was an increase in attention to and research on the disorder. The DSM-IV gave social phobia the alternative name "social anxiety disorder". Research on the psychology and sociology of everyday social anxiety continued. Cognitive behavioural models and therapies were developed for social anxiety disorder. In the 1990s, paroxetine became the first prescription drug in the US approved to treat social anxiety disorder, with others following.

## Signs and symptoms

The 10th version of the International Classification of Diseases (ICD-10) classifies social anxiety as a mental and behavioral disorder.

### Cognitive aspects

In cognitive models of social anxiety disorder, those with social phobias experience dread over how they will present to others. They may feel overly self-conscious, pay high self-attention after the activity, or have high performance standards for themselves. According to the social psychology theory of self-presentation, an affected person attempts to create a well-mannered impression towards others but believes they are unable to do so. Many times, before the potentially anxiety-provoking social situation, they may deliberately review what could go wrong and how to deal with each unexpected case. After the event, they may have the perception that they performed unsatisfactorily. Consequently, they will perceive anything that may have possibly been abnormal as embarrassing. These thoughts may extend for weeks or longer. Cognitive distortions are a hallmark and are learned about in CBT (cognitive-behavioral therapy). Thoughts are often self-defeating and inaccurate. Those with social phobia tend to interpret neutral or ambiguous conversations with a negative outlook and many studies suggest that socially anxious individuals remember more negative memories than those less distressed.

### Behavioral aspects

Social anxiety disorder is a persistent fear of one or more situations in which the person is exposed to possible scrutiny by others and fears that they may do something or act in a way that will be humiliating or embarrassing. It exceeds normal "shyness" as it leads to excessive social avoidance and substantial social or occupational impairment.
Those who have social anxiety disorder fear being judged by others in society. In particular, individuals with social anxiety are nervous in the presence of people with authority and feel uncomfortable during physical examinations. People who have this disorder may behave a certain way or say something and then feel embarrassed or humiliated after. As a result, they often choose to isolate themselves from society to avoid such situations. They may also feel uncomfortable meeting people they do not know and act distant when they are with large groups of people. In some cases, they may show evidence of this disorder by avoiding eye contact, or blushing when someone is talking to them.

### Physiological aspects

Physiological effects may include excessive sweating, nausea, difficulty breathing, shaking, palpitations, and increased heart rate.

### Social aspects

People with SAD avoid situations that most people consider normal. People with SAD avoid all or most social situations and hide from others, which can affect their personal relationships. Social phobia can completely remove people from social situations due to the irrational fear of these situations. People with SAD may be addicted to social media networks, have sleep deprivation, and feel good when they avoid human interactions. SAD can also lead to low self-esteem, negative thoughts, major depressive disorder, sensitivity to criticism, and poor social skills that do not improve. People with SAD experience anxiety in a variety of social situations, from important, meaningful encounters to common situations. These people may feel more nervous in job interviews, dates, interactions with authority, or at work.

### Comorbidity

SAD shows a high degree of co-occurrence with psychiatric disorders. In fact, a population-based study found that 66% of those with SAD had one or more additional mental health disorders. SAD often occurs alongside low self-esteem and most commonly clinical depression. Clinical depression is 1.49 to 3.5 times more likely to occur in those with SAD. Research also indicates that the presence of certain social fears (e.g., avoidance of participating in small groups, avoidance of going to a party) are more likely to trigger comorbid depressive symptoms than other social fears.
Anxiety disorders other than SAD are also common in people with SAD, in particular generalized anxiety disorder. Avoidant personality disorder is likewise highly correlated with SAD, with comorbidity rates ranging from 25% to 89%.
To try to reduce their anxiety and alleviate depression, people with social phobia may use alcohol or other drugs, which can lead to substance use disorders. It is estimated that one-fifth of people with social anxiety disorder also have alcohol use disorder. However, some research suggests SAD is unrelated to, or even protective against alcohol-related problems. Those who have both alcohol use disorder and social anxiety disorder are more likely to avoid group-based treatments and to relapse compared to people who do not have this combination.

## Causes

Research into the causes of social anxiety and social phobia is wide-ranging, encompassing multiple perspectives from neuroscience to sociology. Scientists have yet to pinpoint the exact causes. Studies suggest that genetics can play a part in combination with environmental factors. Social phobia is not caused by other mental disorders or substance use. Generally, social anxiety begins at a specific point in an individual's life. This will develop over time as the person struggles to recover. Eventually, mild social awkwardness can develop into symptoms of social anxiety or phobia. Passive social media usage may cause social anxiety in some people.

### Genetics

It has been shown that there is a two to a 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, and shyness in adoptive parents is significantly correlated with shyness in adopted children.
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 a social anxiety disorder.

### Social experiences

A previous negative social experience can be a trigger to social phobia, perhaps particularly for individuals high in "interpersonal sensitivity". For around half of those diagnosed with social anxiety disorder, a specific traumatic or humiliating social event appears to be associated with the onset or worsening of the disorder; this kind of event appears to be particularly related to specific social phobia, for example, regarding public speaking. As well as direct experiences, observing or hearing about the socially negative experiences of others (e.g. a faux pas committed by someone), or verbal warnings of social problems and dangers, may also make the development of a social anxiety disorder more likely. Social anxiety disorder may be caused by the longer-term effects of not fitting in, or being bullied, rejected, or ignored. Shy adolescents or avoidant adults have emphasized unpleasant experiences with peers or childhood bullying or harassment. In one study, popularity was found to be negatively correlated with social anxiety, and children who were neglected by their peers reported higher social anxiety and fear of negative evaluation than other categories of children. Socially phobic children appear less likely to receive positive reactions from peers, and anxious or inhibited children may isolate themselves.

### Parental influences

Different parenting styles can also contribute to the development of Social Anxiety disorder. The common negative parenting styles, such as overcontrol and criticism can be detrimental for a child to be able to overcome difficult situations. More aggressive and harsh parenting styles that include both verbal abuse and physical punishment are linked with an insecure attachment and risk for Social Anxiety Disorder. On the contrary, positive parenting that fosters a more supportive and warm environment for the child is correlated to a decreased risk of developing this disorder. On the biological level as well, there is strong evidence that states how children from parents with Social Anxiety Disorder have significantly increased risk to the disorder.

### Cultural influences

Cultural factors that have been related to social anxiety disorder include a society's attitude towards shyness and avoidance, affecting the ability to form relationships or access employment or education, and shame. One study found that the effects of parenting are different depending on the culture: American children appear more likely to develop social anxiety disorder if their parents emphasize the importance of others' opinions and use shame as a disciplinary strategy, but this association was not found for Chinese/Chinese-American children. In China, research has indicated that shy-inhibited children are more accepted than their peers and more likely to be considered for leadership and considered competent, in contrast to the findings in Western countries. Purely demographic variables may also play a role.
Problems in developing social skills, or 'social fluency', may be a cause of some social anxiety disorder, through either inability or lack of confidence to interact socially and gain positive reactions and acceptance from others. The studies have been mixed, however, with some studies not finding significant problems in social skills while others have. What does seem clear is that the socially anxious perceive their own social skills to be low. It may be that the increasing need for sophisticated social skills in forming relationships or careers, and an emphasis on assertiveness and competitiveness, is making social anxiety problems more common, at least among the 'middle classes'. An interpersonal or media emphasis on 'normal' or 'attractive' personal characteristics has also been argued to fuel perfectionism and feelings of inferiority or insecurity regarding negative evaluation from others. The need for social acceptance or social standing has been elaborated in other lines of research relating to social anxiety.

### Substance-induced

While alcohol initially relieves social phobia, excessive alcohol misuse can worsen social phobia symptoms and cause panic disorder to develop or worsen during alcohol intoxication and especially during alcohol withdrawal syndrome. This effect is not unique to alcohol but can also occur with long-term use of drugs that have a similar mechanism of action to alcohol such as the benzodiazepines which are sometimes prescribed as tranquillisers. Benzodiazepines possess anti-anxiety properties and can be useful for the short-term treatment of severe anxiety. Like the anticonvulsants, they tend to be mild and well-tolerated, although there is a risk of habit-forming. Benzodiazepines are usually administered orally for the treatment of anxiety; however, occasionally lorazepam or diazepam may be given intravenously for the treatment of panic attacks.
The World Council of Anxiety does not recommend benzodiazepines for the long-term treatment of anxiety due to a range of problems associated with long-term use including tolerance, psychomotor impairment, cognitive and memory impairments, physical dependence and a benzodiazepine withdrawal syndrome upon discontinuation of benzodiazepines. Despite increasing focus on the use of antidepressants and other agents for the treatment of anxiety, benzodiazepines have remained a mainstay of anxiolytic pharmacotherapy due to their robust efficacy, rapid onset of therapeutic effect, and generally favorable side effect profile. Treatment patterns for psychotropic drugs appear to have remained stable over the past decade, with benzodiazepines being the most commonly used medication for panic disorder.
Many people who are addicted to alcohol or prescribed benzodiazepines when it is explained to them they have a choice between ongoing ill mental health or quitting and recovering from their symptoms decide on quitting alcohol or their benzodiazepines. Symptoms may temporarily worsen however, during alcohol withdrawal or benzodiazepine withdrawal.

### Psychological factors

Research has indicated the role of 'core' or 'unconditional' negative beliefs (e.g. "I am inept") and 'conditional' beliefs nearer to the surface (e.g. "If I show myself, I will be rejected"). They are thought to develop based on personality and adverse experiences and to be activated when the person feels under threat. Recent research has also highlighted that conditional beliefs may also be at play (e.g., "If people see I'm anxious, they'll think that I'm weak").
A secondary factor is self-concealment which involves concealing the expression of one's anxiety or its underlying beliefs. One line of work has focused more specifically on the key role of self-presentational concerns. The resulting anxiety states are seen as interfering with social performance and the ability to concentrate on interaction, which in turn creates more social problems, which strengthens the negative schema. Also highlighted has been a high focus on and worry about anxiety symptoms themselves and how they might appear to others. A similar model emphasizes the development of a distorted mental representation of the self and overestimates of the likelihood and consequences of negative evaluation, and of the performance standards that others have. Such cognitive-behavioral models consider the role of negatively biased memories of the past and the processes of rumination after an event, and fearful anticipation before it.
Studies have also highlighted the role of subtle avoidance and defensive factors, and shown how attempts to avoid feared negative evaluations or use of "safety behaviors" can make social interaction more difficult and the anxiety worse in the long run. This work has been influential in the development of cognitive behavioral therapy for social anxiety disorder, which has been shown to have efficacy.

## Diagnosis

ICD-10 defines social phobia as fear of scrutiny by other people leading to avoidance of social situations. The anxiety symptoms may present as a complaint of blushing, hand tremor, nausea, or urgency of urination. Symptoms may progress to panic attacks.
Standardized rating scales such as the Social Phobia Inventory, the SPAI-B, Liebowitz Social Anxiety Scale, and the Social Interaction Anxiety Scale can be used to screen for social anxiety disorder and measure the severity of anxiety.

### DSM-5 diagnostic criteria

Although the DSM defines social anxiety disorder as an intense fear or anxiety of social situations, it makes clear a distinction to separate social anxiety disorder from simply social anxiety or social fear.

#### Social situations

* The anxiety must occur in a social setting under circumstances that are conducive to the possible scrutiny of others.
** For children, the DSM-5 notes that the anxiety must be in a setting with other children and not with adults.
* Social situations induce and are avoided due to the intense feelings of anxiety or fear.
* Social situations must be the cause of anxiety or fear.
The DSM-5 notes that for social anxiety disorder, the fear must be attributed or correlated to social situations and not another condition.

#### Anxiety

* The fear or anxiety is out of reasonable proportion to the context of the situation.
* The fear or anxiety affects an individual for an abnormally long time of 6 months or more.
* There is a significant negative impact on an individual’s life due to the fear or anxiety in a social, professional, or other important area of their life.
To determine a reasonable proportion, an individual’s socio-cultural situation must be taken into account as different cultures have different criteria for differentiating a reasonable fear to a learned behavioral accepted trait in a particular social situation. Furthermore the duration of the fear is used to distinguish the disorder from more common transient social fears that effect particularly, as the DSM notes, children. The last criteria for anxiety is the noticeable and major impact the anxiety or fear has on their life, for example if the fear has no major or noticeable impact on a person’s life it isn’t social anxiety disorder but rather just a social fear or anxiety. However if this fear has a major or noticeable impact in their social, professional, or other important area of their life it is considered a social anxiety disorder.

#### Other causes

* Condition is not an psychological effect induced by a substance (e.g. drugs, alcohol, or medication)
* Condition is not an psychological effect induced by another medical condition
* Condition is not a psychological effect induced by another mental disorder
The symptoms for social anxiety disorder can be attributed to other factors and conditions so the DSM-5 notes it cannot be the effect of another mental disorder, a medical condition, or the effect of a substance.

#### Performance

* Fear is limited to only public speaking or public performing
The DSM-5 notes that performance only type of social anxiety disorder (a subset specific version of this disorder) often affects individual’s professional lives of those involved with public speaking or public performing. These fears can arise in settings other than just an individual’s professional life but are limited to only public social performance situations.

### Differential diagnosis

The DSM-IV criteria stated that an individual cannot receive a diagnosis of social anxiety disorder if their symptoms are better accounted for by one of the autism spectrum disorders such as autism and Asperger syndrome.
Because of its close relationship and overlapping symptoms, treating people with social phobia may help understand the underlying connections to other mental disorders. Social anxiety disorder is often linked to bipolar disorder and attention deficit hyperactivity disorder (ADHD) and some believe that they share an underlying cyclothymic-anxious-sensitive disposition. The co-occurrence of ADHD and social phobia is very high, especially when CDS symptoms are present.

## Treatment
### Psychotherapies

The first-line treatment for social anxiety disorder is cognitive behavioral therapy (CBT), with medications such as selective serotonin reuptake inhibitors (SSRIs) used only in those who are not interested in therapy. According to research studies, combining the use of CBT with escitalopram (a type of SSRI) in contrast to using CBT with a placebo reduced anticipatory speech-state anxiety and increased reductions of social anxiety symptoms, revealing the potential of combining various treatment methods. Self-help based on principles of CBT is a second-line treatment.
There is some emerging evidence for the use of acceptance and commitment therapy (ACT) in the treatment of social anxiety disorder. ACT is considered an offshoot of traditional CBT and emphasizes accepting unpleasant symptoms rather than fighting against them, as well as psychological flexibility – the ability to adapt to changing situational demands, to shift one's perspective, and to balance competing desires. ACT may be useful as a second line treatment for this disorder in situations where CBT is ineffective or refused.
Some studies have suggested social skills training (SST) can help with social anxiety. Examples of social skills focused on during SST for social anxiety disorder include: initiating conversations, establishing friendships, interacting with members of the preferred sex, constructing a speech and assertiveness skills. However, it is not clear whether specific social skills techniques and training are required, rather than just support with general social functioning and exposure to social situations.
There is some evidence that expressive therapies (e.g. painting, drawing or musical therapy) can be effective for treating social anxiety disorder in certain contexts. A 2019 study, for example, found that art therapy produced an "increase in subjective quality of life (both with large effects) and an improvement in accessibility of emotion regulation strategies" in adult women with anxiety. Both VAGA and the American Art Therapy Association run specific workshops for social anxiety disorder.
Furthermore, error-related brain activity varies in accordance to factors that affect the motivational significance of behavioural performance, such as social contexts and personality traits, suggesting that understanding how individuals appraise the relevance of incentives in a given context is crucial for designing interventions to ameliorate or prevent maladaptive patterns of performance evaluation, particularly with regards to social anxiety disorder and substance abuse.
Given the evidence that social anxiety disorder may predict subsequent development of other psychiatric disorders, such as depression, early diagnosis and treatment is important. Social anxiety disorder remains under-recognized in primary care practice, with patients often presenting for treatment only after the onset of complications such as clinical depression or substance use disorders.

### Medications
#### SSRIs

Selective serotonin reuptake inhibitors (SSRIs), a class of antidepressants, are the first choice of medication for generalized social phobia but a second-line treatment. Compared to older forms of medication, there is less risk of tolerability and drug dependency associated with SSRIs.
Paroxetine and paroxetine CR, sertraline, escitalopram, venlafaxine XR and fluvoxamine CR (Luvox CR) are all approved for SAD and are all effective for it, especially paroxetine. All SSRIs are somewhat effective for social anxiety except fluoxetine which was equivalent to placebo in all clinical trials. Paroxetine was able to change personality and significantly increase extraversion.
Other SSRIs like fluvoxamine, escitalopram and sertraline showed reduction of social anxiety symptoms, including anxiety, sensitivity to rejection and hostility.
General side-effects are common during the first weeks while the body adjusts to the drug. Symptoms may include headaches, nausea, insomnia and changes in sexual behavior. Treatment safety during pregnancy has not been established. In late 2004 much media attention was given to a proposed link between SSRI use and suicidality [a term that encompasses suicidal ideation and attempts at suicide as well as suicide]. For this reason, [although evidential causality between SSRI use and actual suicide has not been demonstrated] the use of SSRIs in pediatric cases of depression is now recognized by the Food and Drug Administration as warranting a cautionary statement to the parents of children who may be prescribed SSRIs by a family doctor. Recent studies have shown no increase in rates of suicide. These tests, however, represent those diagnosed with depression, not necessarily with social anxiety disorder.
In addition, studies show that more socially phobic patients treated with anti-depressant medication develop hypomania than non-phobic controls. The hypomania can be seen as the medication creating a new problem.

#### Other drugs

Other prescription drugs are also used, if other methods are not effective. Before the introduction of SSRIs, monoamine oxidase inhibitors (MAOIs) such as phenelzine were frequently used in the treatment of social anxiety. Evidence continues to indicate that MAOIs are effective in the treatment and management of social anxiety disorder and they are still used, but generally only as a last resort medication, owing to concerns about dietary restrictions, possible adverse drug interactions and a recommendation of multiple doses per day. A newer type of this medication, reversible inhibitors of monoamine oxidase subtype A (RIMAs) such as the drug moclobemide, bind reversibly to the MAO-A enzyme, greatly reducing the risk of hypertensive crisis with dietary tyramine intake. However, RIMAs have been found to be less efficacious for social anxiety disorder than irreversible MAOIs like phenelzine.
Benzodiazepines are an alternative to SSRIs. These drugs' recommended usage is for short-term relief, meaning a limited time frame of over a year, of severe, disabling anxiety. Although benzodiazepines are still sometimes prescribed for long-term everyday use in some countries, there is concern over the development of drug tolerance, dependency and misuse. It has been recommended that benzodiazepines be considered only for individuals who fail to respond to other medications. Benzodiazepines augment the action of GABA, the major inhibitory neurotransmitter in the brain; effects usually begin to appear within minutes or hours. In most patients, tolerance rapidly develops to the sedative effects of benzodiazepines, but not to the anxiolytic effects. Long-term use of a benzodiazepine may result in physical dependence, and abrupt discontinuation of the drug should be avoided due to high potential for withdrawal symptoms (including tremor, insomnia, and in rare cases, seizures). A gradual tapering of the dose of clonazepam (a decrease of 0.25 mg every 2 weeks), however, is well tolerated by patients with social anxiety disorder. Benzodiazepines are not recommended as monotherapy for patients who have major depression in addition to social anxiety disorder and should be avoided in patients with a history of substance use.
Certain anticonvulsant drugs such as gabapentin and pregabalin are effective in social anxiety disorder and may be a possible treatment alternative to benzodiazepines. However there is concern regarding their off-label use due to the lack of strong scientific evidence for their efficacy and their proven side effects.
Serotonin-norepinephrine reuptake inhibitors (SNRIs) such as venlafaxine have shown similar effectiveness to the SSRIs. In Japan, Milnacipran is used in the treatment of Taijin kyofusho, a Japanese variant of social anxiety disorder. The atypical antidepressants mirtazapine and bupropion have been studied for the treatment of social anxiety disorder, and rendered mixed results.
Some people with a form of social phobia called performance phobia have been helped by beta-blockers, such as propranolol, commonly used to control high blood pressure.

## Epidemiology

| Country | Prevalence |
| United States | 2–7% |
| England | 0.4% (children) |
| Scotland | 1.8% (children) |
| Wales | 0.6% (children) |
| Australia | 1–2.7% |
| Brazil | 4.7–7.9% |
| India | 12.8% (adolescents) |
| Iran | 0.8% |
| Israel | 4.5% |
| Nigeria | 9.4% (university students) |
| Sweden | 15.6% (university students) |
| Turkey | 9.6% (university students) |
| Poland | 7–9% (2002) |
| Taiwan | 7% children (2002~2008) |
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, substance use, and other psychological conflicts.
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 use disorder, and the most common of the anxiety disorders. According to US 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 US 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 and 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.

## Research

Although social anxiety disorder has been under study for decades, the underlying neurobiology is not well understood. Neurotransmitters under research include serotonin, dopamine, and glutamate. Neuroimaging technologies are in use to clarify brain regions involved. The amygdala is a primary brain structure involved in SAD, as explored in imaging studies.
Parenting that is intrusive or controlling and stressful life events may increase the risk for SAD development during childhood, extending into adult years. Genetic factors may have a role, although genetic biomarkers are not specifically identified.