INTRODUCTION — Specific phobia is an anxiety disorder characterized by clinically-significant fear of a particular object or situation that typically leads to avoidance behavior. Phobic fears include animals, insects, heights, water, enclosed places, driving, flying, and choking or vomiting. Some specific phobias involve responses to medical procedures, such as injections, dental work, or blood. (See "Treatment of specific phobias of clinical procedures in adults".)
Specific phobias are among the most common mental disorders and can be highly disabling [1,2]. However, they are also among the most treatable mental disorders [3-6]. Despite availability of efficacious treatments, the majority of individuals with specific phobias are hesitant to seek treatment [7]. This may be due to lack of knowledge that the phobia is treatable, embarrassment to disclose the phobia to a health professional, accommodation of the phobia through avoidance, or fear of increased anxiety or discomfort in the course of treatment [5].
Pharmacotherapy for specific phobia in adults is discussed here. The epidemiology, pathogenesis, clinical manifestations, course, and diagnosis of specific phobia in adults are also discussed separately. Psychotherapy for specific phobia in adults is also discussed separately. Specific phobias relating to clinical procedures (eg, blood-injection-injury phobia) and other manifestations of acute procedural anxiety are also discussed separately. Specific phobia and other fears in children are also discussed separately. (See "Specific phobia in adults: Epidemiology, clinical manifestations, course and diagnosis" and "Cognitive-behavioral therapies for specific phobia in adults" and "Acute procedure anxiety in adults: Epidemiology, clinical manifestations, and course" and "Treatment of acute procedural anxiety in adults" and "Overview of fears and phobias in children and adolescents".).
APPROACH TO TREATMENT — Our approach to selecting treatments for specific phobia in adults is reviewed separately. (See "Approach to treating specific phobia in adults".)
First-line treatment for specific phobia is cognitive-behavioral therapy (CBT) that includes exposure treatment [8]. Pharmacotherapy, specifically benzodiazepines have a limited role in treatment of specific phobia. Medications are used when CBT with exposure is not available or feasible, or when patients prefer medication to CBT despite the lack of comparably robust supporting evidence from clinical trials.
MEDICATIONS
Benzodiazepines
Indications — Among medications, benzodiazepines are most often used in the treatment of specific phobia when the phobic stimulus is infrequently encountered and unavoidable, such as in the treatment of a flying phobia. Patients who have experienced intense fear on previous occasions when undertaking these activities may wish to have a reasonable certainty that their anxiety can be lessened if they were to experience the feared stimulus again.
Efficacy — There are no rigorous data from clinical trials finding that benzodiazepines are efficacious for specific phobia [9]. As an example, a randomized trial of 28 women with flying phobia who traveled on two flights over a one-week period found that alprazolam led to reduced anxiety but a greater physiologic response on the first flight, compared to placebo, and increased anxiety, physiologic response, and panic on the second flight [10].
In our clinical experience, flying phobia anxiety can be managed with benzodiazepines short-term, ie, for the length of a flight. However, well-designed randomized trials are needed to test their efficacy [11].
Administration — A benzodiazepine with a relatively short onset (eg, lorazepam 0.5 to 2 mg) can be taken 30 minutes before the stimulus is encountered. A sedating benzodiazepine such as lorazepam is most useful for treating phobias that do not involve performance that could be adversely affected by the medication.
Patients should be advised to take a test dose prior to using it for the phobic situation to ensure it does not lead to oversedation. Patients should be warned not to consume alcohol and the drug together due to the risk of additive side effects such as sedation, confusion, and impaired coordination.
Side effects of benzodiazepines include sedation, impaired psychomotor performance, amnesia, and abuse as well as dependence and withdrawal symptoms after long-term treatment [12].
The risk of abuse of benzodiazepines is largely confined to individuals with a substance abuse history or problem, though a family history of substance abuse may be a risk factor for some individuals [13]. Treating patients who are no longer currently abusing substances with benzodiazepines is not absolutely contraindicated, but would require closer monitoring and, in some cases, the use of longer-acting benzodiazepines with slower onset of action (eg, clonazepam) that may reduce abuse liability. Dose escalation can be discouraged by prescribing a minimal supply of pills for infrequent use. In addition, benzodiazepines may interfere with engagement in cognitive-behavioral therapy (CBT) by perpetuating avoidance behaviors, and their use is limited when a patient is completing a course of CBT treatment [14,15].
Selective serotonin reuptake inhibitors — There is minimal evidence to support the use of selective serotonin reuptake inhibitors (SSRIs) for the treatment of specific phobias [16,17]. In addition, SSRIs may be associated with significant side effects (eg, weight gain that may not be easily reversed).
Efficacy — There have been only two small trials with mixed results testing SSRIs in specific phobia. Larger trials are needed to determine the efficacy of these medications:
●A randomized trial compared 12 weeks of treatment with escitalopram (5 to 20 mg/day) to placebo in 12 patients with specific phobia (types included enclosed spaces, flying, heights, dentist, and animals) [16]. A statistically-significant difference was not seen between the two groups, though a trend in favor of medication was observed in this small trial.
●A randomized trial compared four weeks of treatment with paroxetine (20 mg/day) to placebo in 11 patients with specific phobia (types included confined spaces, storms, flying, animals, heights, driving) [17]. Patients treated with paroxetine showed greater reductions in fear and avoidance compared to the placebo group.
Investigational medications — Given the limited evidence on the efficacy of these drugs in the disorder, we do not recommend any currently for clinical use in the treatment of specific phobias.
Cycloserine — D-cycloserine (DCS), a partial N-methyl-D-aspartate receptor agonist, has been found to have a small effect in augmenting CBT in the treatment of specific phobia [18] other anxiety disorders [19]. The medication’s hypothesized mechanism of action is through facilitation of extinction learning.
In a randomized trial, 28 subjects with a height phobia were randomly assigned to receive cycloserine or placebo in augmentation of virtual reality exposure [18]. A single dose of the medication (either 50 mg or 500 mg) or placebo was administered 30 to 60 minutes prior the exposure session. Patients who received either dosage of cycloserine plus exposure experienced greater reduction in anxiety symptoms of height phobia than patients who received placebo plus exposure; the difference between groups was seen following each treatment session and on assessment three months following treatment.
Preliminary evidence suggests that DCS may be useful principally when taken after successful exposure sessions. In a clinical trial of virtual reality exposure followed by DCS in 15 patients with height phobia, DCS was more likely to reduce anxiety in patients who experienced a positive response to exposure [20].
Hydrocortisone — Two trials have found hydrocortisone, a glucocorticoid, to effectively augment CBT in the treatment of specific phobia [21,22]. While the mechanism of action is not known, endogenous glucocorticoids have been found to be released in persons experiencing fearful situations.
●Forty patients with a height phobia were randomly assigned to receive hydrocortisone 20 mg taken orally or placebo one hour before each of two sessions of virtual reality exposure-based CBT [21]. Exposure therapy augmented by hydrocortisone led to a greater reduction in fear of heights compared to placebo-augmented exposure, as assessed following treatment and at a one-month post-treatment. The reduction in anxiety was accompanied by lowered physiological arousal measured by skin conductance (sweating) during the exposure task.
●Twenty patients with a spider phobia were randomly assigned to receive hydrocortisone 10 mg taken orally or placebo one hour prior to exposure to a picture of a spider [22]. Patients receiving hydrocortisone experienced a greater reduction in stimulus-induced fear compared to placebo.
Methylene blue — A randomized trial in 42 patients with claustrophobia found that administration of 260 mg of methylene blue versus placebo immediately after extinction training was efficacious in reducing fear at one-month follow-up, among those for whom the training was successful [23].
Quetiapine — A randomized clinical trial with 58 spider phobic subjects compared quetiapine to placebo, administered before a single virtual reality exposure session [24]. A greater reduction on a visual analogue scale for somatic anxiety was found in quetiapine-treated patients compared with the placebo group.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Anxiety and anxiety disorders in adults".)
SUMMARY
●Our approach to selecting treatments for specific phobia in adults is reviewed separately. (See "Approach to treating specific phobia in adults".)
●There is minimal evidence to support the use of medication to treat specific phobia. Benzodiazepines may be used when cognitive-behavioral therapy (CBT) is unavailable, when patients prefer medication to CBT despite education about their relative risks and benefits, or when time before encountering the phobic stimulus is insufficient for CBT. (See 'Approach to treatment' above.)
●Benzodiazepines, which take effect within minutes of administration, are best used for specific phobia with an infrequently encountered stimulus. They are best suited for patients who lack a history of a substance-use disorder and for situations where the drug’s sedating effects do not interfere with functioning (eg, as a passenger on a plane flight). (See 'Benzodiazepines' above.)
●Small clinical trials of selective serotonin reuptake inhibitors (SSRIs) with mixed results in the treatment of specific phobias provide insufficient support for the use of SSRIs for the disorder. SSRIs, which can take four to six weeks before the onset of action of their clinical effects, also may be associated with significant side effects (eg, weight gain that may not be easily reversed). (See 'Selective serotonin reuptake inhibitors' above.)
●Other medications, including d-cycloserine, hydrocortisone, and quetiapine, are under investigation for use in specific phobia. Based on the current state of evidence, however, none are currently recommended for use. (See 'Investigational medications' above.)
