Overview
Definition
A phobia is defined as an irrational fear that results in avoidance of the feared subject, activity, or situation.
- The fear can occur in anticipation of the situation/activity, during exposure, or even upon hearing the name of the stimulus.
- Patients with specific phobia might have a good insight, knowing that their fear is excessive, or might have poor insight.
- Patients commonly have multiple specific phobias, and each would need to be specified in a diagnosis.
Epidemiology
- The estimated lifetime prevalence of social phobia in the United States is 7%–12.5%.
- More common in females than in males
- Bimodal age at onset:
- Blood-injection injury and natural environment phobias occur in childhood.
- Situational phobias more often occur in adulthood.
Pathophysiology
- Genetics:
- 1st-degree relatives of individuals with specific phobias have an increased risk (up to 31%) of having the disorder, but with a different stimulus.
- Twin studies point to a stronger influence of environmental factors than genetic factors.
- Neurobiologic: Hyperactivation of the amygdala and insula (structures involved in negative emotional responses) has been associated with phobic disorders.
- Personality traits:
- Disgust sensitivity: predisposition to experience disgust in response to certain stimuli (certain animals or blood injections)
- Anxiety sensitivity: fear of the sensations or behaviors of anxiety due to the belief that the anxiety symptoms are harmful
- Environmental factors:
- Traumatic events, the associated stress, prior and subsequent exposure to a stimulus, and the support obtained affect specific phobias.
- Processes that lead to fear development:
- Direct conditioning: being hurt or frightened or having the feeling of helplessness leads to anxiety toward the situation/subject.
- Vicarious acquisition: observing someone with the fearful or anxious behavior
- Informational transmission: obtaining information from others or through media (e.g., shark attacks, plane crashes)
Clinical Presentation and Diagnosis
Specifiers
Main types of specific phobias based on the nature of the stimulus:
- Animal:
- Spiders: arachnophobia
- Dogs: cynophobia
- Insects: entomophobia
- Natural environment:
- Heights: acrophobia
- Water: aquaphobia
- Thunderstorms: astraphobia
- Blood-injection injury:
- Injections/needles: trypanophobia or belenophobia
- Dental procedure: odontophobia
- Situational:
- Flying: aviophobia
- Enclosed places: claustrophobia
- Other (cannot be categorized as above):
- Costumed characters: masklophobia
- Loud sounds: phonophobia or ligyrophobia
- Vomiting: emetophobia
Clinical features and diagnosis
- Patients present with:
- Excessive anxiety about, or fear of, a specific object or situation
- This behavior is almost always provoked when exposed to the stimulus:
- Intense fear, with physiologic arousal (↑ HR or BP)
- Crying, clinging, freezing in children
- Avoidance behavior
- The fear and anxiety lead to functional impairment (e.g., avoids travel because of fear of flying, cannot find a job because of fear of driving).
- Symptoms persist ≥ 6 months
- The fear and anxiety is not due to any underlying medical condition mental disorder or to substance abuse.
- Diagnosis is based on the presenting symptoms.
- Without treatment, the phobia persists throughout the lifetime.
Management
- Specific phobia is treatable, but very few patients seek treatment.
- Psychotherapy:
- Exposure-based CBT: 1st-line treatment
- Goal: desensitize patient to source of phobia
- In vivo exposure: most effective long-term treatment for specific phobias
- Pharmacotherapy:
- Generally, medications alone are not useful in this disorder except in certain situations, as anxiety may return upon discontinuation of medications.
- Short-acting benzodiazepines might be used in patients with claustrophobia (fear of enclosed places, such as an MRI machine).
- D-cycloserine (DCS):
- Partial N-methyl-d-aspartate (NMDA) receptor agonist
- Investigational, but shows some evidence of augmenting CBT during exposure therapy
Other Anxiety Disorders
The following table summarizes the most important information about anxiety disorders.
| Condition | Most important features | Duration | Treatment |
|---|---|---|---|
| Panic disorder | Recurrent and unexpected abrupt surges (within minutes) of intense fear or discomfort | ≥ 1 month |
|
| Generalized anxiety disorder | Chronic multiple worries usually about issues, events, activities | ≥ 6 months | Combination of antidepressants (SSRIs) and CBT |
| Specific phobia | Unreasonable fear of a certain object or situations | ≥ 6 months |
|
| Social phobia (social anxiety disorder) | Fear or avoidance of social interactions due to concerns about being embarrassed | ≥ 6 months |
|
| Agoraphobia | Fear of being in situations or places where it is difficult to leave or escape | ≥ 6 months | 1st-line: SSRIs or CBT |
| Separation anxiety disorder | Fear of being separated from attachment figures | ≥ 1 month |
|
| Illness anxiety disorder | Anxiety arises from concerns about having or acquiring a certain illness. | ≥ 6 months |
|
| Substance- or drug-induced anxiety disorder |
| ||
SSRIs: selective serotonin reuptake inhibitors
Differential Diagnosis
- Panic disorder: chronic mental disorder marked by recurrent and episodic panic attacks that occur abruptly without a trigger. Panic disorder is associated with anxiety or fear of having another attack or its complications and some behavioral changes. If the panic attack is triggered by a known, identified trigger, then the correct diagnosis would be specific phobia.
- Social phobia: also called social anxiety disorder (SAD). Social phobia is the fear or avoidance of social interactions because of concerns about being embarrassed, occurring in > 1 social situation for > 6 months. Treatment includes CBT, antidepressants (SSRIs, serotonin–norepinephrine reuptake inhibitor (SNRIs)), and β-blockers for performance-only subtypes. People with social phobia are afraid of being negatively judged by others.
- Intoxication (on cocaine or hallucinogens): Patients with cocaine use disorder or hallucinogen use disorder can develop a specific phobia when they are intoxicated with either substance. Symptoms of intoxication include agitation, psychosis, hemodynamic instability (hypertension, tachycardia), diaphoresis, and mydriasis. Acute intoxication is distinguished from specific phobia by history taking, physical exam, and urine toxicology screen.
- Agoraphobia: fear or anxiety occurring while facing different situations in which it would be difficult to leave or to obtain help in the event of having panic-like symptoms. Situations include being in public or open spaces, crowds, or public transport. In specific phobia, multiple fears are present (e.g., getting hurt by a spider, being stuck in an elevator). In agoraphobia, there is fear of panic symptoms and being unable to get help or escape.
References
- Choy, Y. (2018). Treatment of specific phobias of clinical procedures in adults. UpToDate. Retrieved June 26, 2021, from https://www.uptodate.com/contents/treatment-of-specific-phobias-of-clinical-procedures-in-adults
- Dave, P. (2017). Clinical management of anxiety disorders. Retrieved June 22, 2021. https://www.researchgate.net/publication/348489972_Clinical_Management_of_Anxiety_Disorders
- Grant, J. (2021). Overview of anxiety disorders. Retrieved June 22, 2021. https://www.researchgate.net/publication/348495093_Overview_of_Anxiety_Disorders
- McCabe, R. (2021). Specific phobia in adults: Epidemiology, clinical manifestations, course and diagnosis. UpToDate. Retrieved June 26, 2021, from https://www.uptodate.com/contents/specific-phobia-in-adults-epidemiology-clinical-manifestations-course-and-diagnosis
- Palkar, P. (2020). Neurobiology of anxiety disorders. Retrieved June 22, 2021, from https://www.researchgate.net/publication/341407589_Neurobiology_of_Anxiety_Disorders
- Sadock, B. J., Sadock, V. A., Ruiz, P. (2014). Anxiety disorders. Chapter 9 of Kaplan and Sadock’s Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry, 11th ed. Philadelphia: Lippincott Williams and Wilkins, pp. 387–417.
