Phobic Disorders 

A phobia is defined as an irrational fear that produces a conscious avoidance of the feared subject, activity, or situation. The affected person usually recognizes that the reaction is excessive. According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)^[1] and its subsequent Text Revision (DSM-IV-TR), phobic disorders can be divided into 3 types: social phobia (now called social anxiety disorder), specific (simple) phobias, and agoraphobia.

Social anxiety disorder is a strong, persisting fear of an interpersonal situation in which embarrassment can occur. Specific phobia is an overwhelming, persisting fear of an object or situation. Agoraphobia is defined as the fear of being alone in public places (eg, a supermarket), particularly places from which a rapid exit would be difficult in the course of a panic attack; at least 75% of patients with agoraphobia experience panic disorder as well.

Collectively, phobic disorders are the most common forms of psychiatric illness, surpassing rates of mood disorders and substance abuse. Anxiety linked to a specific object or situation is the most common subtype. Severity can range from mild and unobtrusive to severe and can result in incapacity to work, travel, or interact with others.

Social anxiety disorder

Social anxiety disorder has been described as far back as Hippocrates, when it was called erythrophobia, which is a fear of blushing in front of others. Social anxiety disorder is now considered a disorder distinct from other phobias. In the first 2 versions of the DSM, social phobia was not conceptualized as a stand-alone diagnosis; however, starting with the DSM-III-R, the disorder could be diagnosed separately in the presence of multiple social fears and other comorbid conditions.

Specific phobia

Specific phobia is more common than social anxiety disorder (social phobia). The DSM-IV-TR describes the following types of specific phobia^[1] :

• Animal type – Fear of dogs (cynophobia), cats (ailurophobia), bees (apiphobia), spiders (arachnophobia), snakes (ophidiophobia), or other animals
• Natural environment type – Fear of heights (acrophobia), water (hydrophobia), or thunderstorms (astraphobia)
• Blood injection/injury type – Algophobia (pain), rhabdophobia (the fear of being beaten)
• Situational type – Fear of flying (pteromerhanophobia), elevators, or enclosed spaces
• Other

Go to Anxiety Disorder, Specific Phobia for complete information on this topic.

Agoraphobia

Agoraphobia is defined by the experience of overwhelming anxiety in situations where it would be embarrassing, or from where it might be difficult to escape or get help. Examples include being in a crowd or at home alone, being on a bridge (as long as it is not due to being afraid of heights) or in a car, bus, train, or plane (as long as it is not due to fear of flying).

Go to Anxiety Disorders and Generalized Anxiety Disorder for complete information on these topics.

Several theories are postulated for the biologic etiology of phobic disorders, most focusing on the dysregulation of endogenous biogenic amines. Sympathetic nervous system activation is common in phobic disorders, resulting in elevations in heart rate and blood pressure, as well as symptoms such as tremor, palpitations, sweating, dyspnea, dizziness, and/or paresthesias.^[2]

Psychologic theories range from explaining anxiety as a displacement of an intrapsychic conflict (psychodynamic models) to conditioning (learned) paradigms (the cognitive-behavior models). Many of these theories capture portions of the disorder.

A psychoanalyst would likely conceptualize social anxiety as a symptom of a deeper conflict—for instance, low self-esteem or unresolved conflicts with internal objects. The treatment uses exploration with the goal of understanding the underlying conflict. A behaviorist would see phobia as a learned, conditioned response resulting from a past association with a situation with negative emotional valence at the time of association (eg, social situations are avoided, because intense anxiety was originally experienced in that setting). Even if no danger is posed in most social encounters, an avoidance response has been linked to these situations. Treatment from this perspective aims to weaken and eventually separate the specific response from the stimulus.

Genetic factors seem to play a role in both social anxiety disorder (social phobia) and specific (simple) phobia. Based on family and twin studies, the risk for specific phobias and social anxiety appears to be moderately heritable.^{[3, 4]}

See also Etiology.

Neurobiologic and psychologic theories as well as familial patterns have contributed to understanding the underlying causes of phobic disorders.

Neurobiologic theories – Social anxiety disorder

Functional brain imaging studies of individuals engaged in public speaking suggest that patients with social anxiety disorder (social phobia) tend to overactivate a circuit involving the amygdala (face recognition, negative emotions) and hippocampus, which might be the substrate for the exaggerated fear response.^[5] At the same time, the patients with social anxiety disorder show a relative increase in their dorsolateral prefrontal and temporal activation, which might be the result of a poor ability to efficiently process (inhibit) the excessive fear response.^[6]

Positron emission tomography (PET) studies have shown lower serotonin (5-HT) 1A binding in the amygdala and mesiofrontal areas and negative correlations between cortisol plasma levels, and 5-HT1A binding in the amygdala, hippocampus, and retrosplenial cortex have been reported in patients with social anxiety disorder.^{[7, 8]}

A recent review of 48 neuroimaging articles regarding social anxiety disorder concluded that increased activity in the limbic and paralimbic regions is the most consistent finding (across imaging techniques) in social anxiety disorder.^[9]

Neurobiologic theories – Specific phobia

Phobic reactions may result from activation of object recognition and emotional processing areas co-occurring with inhibition of the prefrontal areas that are responsible for cognitive control over emotion-triggering.^[10]

A PET study showed that the phobic response in spider (SpP) and snake (SnP) phobia elevated the regional cerebral blood flow (rCBF) in the right amygdala, cerebellum, and the left visual cortex but reduced the rCBF in the prefrontal, orbitofrontal, ventromedial, primary somatosensory cortex, and auditory cortices. A positive correlation between amygdala activation and the subjective fear response emphasizes the importance of amygdala in this fear-phobia circuit.^[10]

Partially distinct neurobiologic substrates have been suggested for different types of phobias. A functional magnetic resonance imaging (fMRI) study of patients with SpP and blood injection-injury phobia (BiiP) reported similar activation in several common regions across the 2 groups (thalamus, cerebellum, occipitotemporal regions) but also group-specific activation in the dorsal anterior cingulate gyrus and the anterior insula in the patients with SpP.^[11]

Increased fMRI activation of the dorsal anterior cingulate cortex (ACC), insula, thalamus, and visual areas in SpP as well as the bed nucleus of the stria terminalis has been reported in patients with SpP relative to normal controls during an anticipatory task of phobia-relevant versus neutral stimulation.^[12]

Psychologic theories

Social anxiety disorder (social phobia) can be initiated by traumatic social experience (eg, embarrassment) or by social skills deficits that produce recurring negative experiences. A hypersensitivity to rejection, perhaps related to serotonergic or dopaminergic dysfunction, is present. It is thought that social anxiety disorder appears to be an interaction between biologic and genetic factors and environmental events.

Specific (simple) phobia can be acquired by conditioning, modeling, a traumatic experience, or may even have a genetic component (eg, blood-injury phobia).

Agoraphobia may be the result of repeat, unexpected panic attacks, which, in turn, may be linked to cognitive distortions, conditioned responses, and/or abnormalities in noradrenergic, serotonergic, or gamma-aminobutyric acid (GABA)–related neurotransmission.

Familial pattern

A familial pattern has been reported for both social anxiety disorder (social phobia) and specific (simple) phobia. Generalized social anxiety disorder further increases the risk of familial transmission. For specific phobias, first-degree relatives appear to have an increased risk for the type of phobia rather than the specific trigger. For example, an increased rate of animal phobias rather than a phobia to a specific animal can be seen within the same family.^[1]

The National Comorbidity Survey reported the following lifetime (and 30-day) prevalence estimates: 13.3% (and 4.5%) for social anxiety disorder (social phobia), 11.3% (and 5.5%) for specific (simple) phobia, and 6.7% (and 2.3%) for agoraphobia.^{[13, 14]} The occurrence of phobias appears equally distributed among races.

These disorders appear to have a higher incidence among women: social anxiety disorder is more common in women, but more men seek treatment due to career issues; specific phobia has a female-to-male ratio of 2:1; and agoraphobia has a female-to-male ratio of 2-3:1.

Most anxiety disorders appear earlier in life. In fact, earlier median ages at illness onset are reported for specific phobia (15 y) and social phobia (16 y) than for agoraphobia (29 y).^[13] Most specific phobias develop during childhood and eventually disappear. Those that persist into adulthood rarely go away without treatment. Animal phobias are most common at the elementary school level.

Social anxiety disorder

Social anxiety disorder (social phobia) is the most common anxiety disorder; this condition has an early age of onset—by age 11 years in about 50% and by age 20 years in about 80% of individuals who have the diagnosis—and it is a risk factor for subsequent depressive illness and substance abuse.^[15]

Specific phobia

The age of onset of specific (simple) phobia depends on the phobia. In general, specific phobia appears earlier than social phobia or agoraphobia. Examples include the following:

• Animal phobia appears at a mean age of 7 years.
• Blood phobia appears at a mean age of 9 years.
• Dental phobia appears at a mean age of 12 years.
• Claustrophobia appears at a mean age of 20 years.

Agoraphobia usually begins in late adolescence to early adulthood.

Considerable evidence shows that social anxiety results in significant functional impairment and decreased quality of life.^{[16, 17]} Despite evidence of impairment, only a minority of individuals with specific (simple) phobia ever seek professional treatment.

Phobias are highly comorbid. Most comorbid social anxiety disorders (social phobias) and specific phobias are temporally primary, whereas most comorbid agoraphobia is temporally secondary. Comorbid phobias are generally more severe than pure phobias.

Social anxiety disorder is also frequently comorbid with major depressive disorder (MDD) and atypical depression, which results in increased disability.^{[17, 18]} In clinical samples, more than 95% of the patients reporting agoraphobia also present with panic disorder, whereas in epidemiologic samples, simple agoraphobia appears to be more prevalent than panic disorder with agoraphobia.^[1]

Controversy exists whether anxiety disorders in general and phobias in particular are independently associated with suicidal ideation and suicide attempts (ie, after adjusting for comorbid mental disorders). New evidence suggests that even after adjusting for sociodemographic factors and other mental disorders, the baseline presence of any anxiety disorder—including agoraphobia, social anxiety disorder, and specific phobias—is significantly associated with suicidal ideation and suicide attempts. Additionally, the presence of any anxiety disorder, phobias included, in combination with a mood disorder appears to increase likelihood of suicide attempts compared with a mood disorder alone.^[19]

Significant morbidity is also possible in terms of work and relationships, especially in social phobia and agoraphobia.

Most patients respond to treatment, with good resolution of symptoms. Patients with specific phobia often recover to the highest level of functioning, whereas those with agoraphobia or social anxiety disorders may have residual symptoms or run a greater risk of relapse even after successful treatment. In fact, patients with social anxiety disorders with extensive deficits in social skills may not respond well to treatment; in a prospective, naturalistic, longitudinal, multicenter study of adults, social anxiety disorder had the smallest probability of recovery after 12 years of follow-up.^[20]

The prognosis is determined by several factors, including the following:

• Severity of diagnosis
• level of functioning before onset of symptoms
• Degree of motivation for treatment
• level of support (eg, family, friends, work, school)

Ability to comply with medication and/or psychotherapeutic regimen

The treating physician should begin a process of education, not only for the patient but also for family and friends who may be confused about the diagnosis and the need for treatment. Abilities that most people take for granted, such as socializing at gatherings or riding in a small elevator, may seem commonplace, but patients who experience phobias have tremendous difficulty in these areas and can be helped significantly by a caring support system. Family and friends can encourage the patient to confront fears, help the patient when necessary (with medication compliance or confronting fearful situations), and can also learn when to stay out of the way and allow the patient to venture forth on his or her own.

Numerous books and self-help groups are available. In addition, patient advocacy groups exist nationwide to provide patients with information, presentations, and conferences. The following Websites are helpful:

• Social Phobia/Social Anxiety Association
• American Psychiatric Association
• Anxiety Disorders Association of America
• MedlinePlus, Phobias
• MayoClinic.com, Phobias
• US Food and Drug Administration (FDA), Fighting Phobias, The Things That Go Bump in the Mind

For patient education information, see eMedicine's Anxiety Center, as well as Anxiety, Panic Attacks, and Hyperventilation.