Excerpt from Phobic Disorders

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Background

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. Phobic disorders can be divided into 3 types: social phobia, specific phobias, and agoraphobia.

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) defines social phobia as a strong, persisting fear of an interpersonal situation in which embarrassment can occur and specific phobia as a strong, 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.

Social phobia, now called social anxiety disorder (SAD), 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 DSM-III-R, the disorder could be diagnosed separately in the presence of multiple social fears and other comorbid conditions.

Specific phobia is more common than social phobia. The following types of specific phobia are described:

• Animal type (fear of dogs, spiders, snakes, or other animals)
• Natural environment type (eg, height, water, storm)
• Blood injection/injury type
• Situational type (eg, planes, elevators, enclosed spaces)
• Other

Collectively, these 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.

See Medscape's Anxiety Disorders Resource Center.

Pathophysiology

Several theories are postulated for the biological 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

Psychological 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 an 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 phobia and specific phobia. Based on family and twin studies, the risk for specific phobias and social anxiety appears to be moderately heritable.^{3, 4}

Frequency

United States

The National Comorbidity Survey reported the following lifetime (and 30-day) prevalence estimates: 6.7% (and 2.3%) for agoraphobia, 11.3% (and 5.5%) for simple phobia, and 13.3% (and 4.5%) for social phobia.^{5, 6} 

Social phobia is the most common anxiety disorder; it has an early age of onset—by age 11 years in about 50% and by age 20 years in about 80% of individuals that have the diagnosis—and it is a risk factor for subsequent depressive illness and substance abuse.⁷

International

European data generally are similar to those of the United States.

Mortality/Morbidity

Considerable evidence shows that social anxiety results in significant functional impairment and decreased quality of life.^{8, 9} Despite evidence of impairment, only a minority of individuals with simple phobia ever seek professional treatment.

Phobias are highly comorbid. Most comorbid simple and social phobias are temporally primary, while most comorbid agoraphobia is temporally secondary. Comorbid phobias are generally more severe than pure phobias. Social phobia is also frequently comorbid with major depressive disorder and atypical depression, which results in increased disability.^{9, 10}

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 socio-demographic factors and other mental disorders, baseline presence of any anxiety disorder, including agoraphobia, social phobia, 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.¹¹

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

Race

The occurrence of phobias appears equally distributed among races.

Sex

• Specific phobia has a female-to-male ratio of 2:1.
• Social phobia is more common in women, but more men seek treatment due to career issues.
• Agoraphobia has a female-to-male ratio of 2-3:1.

Age

Most anxiety disorders appear earlier in life. Animal phobias are most common at the elementary school level. Earlier median ages at illness onset are reported for simple phobia (15 y) and social phobia (16 y) than for agoraphobia (29 y).⁵

• Specific phobia: Age of onset 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.
  • Most simple phobias develop during childhood and eventually disappear. Those that persist into adulthood rarely go away without treatment.
• Social phobia: Most social phobias begin before age 20 years.
• Agoraphobia: Agoraphobia usually begins in late adolescence to early adulthood.

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