Phobias are the most common anxiety disorder. Specific phobia is characterized by extreme and persistent fear of specific objects or situations that present little or no real threat. The condition has behavioral, cognitive, and physiologic manifestations. (See Etiology.)
Functional magnetic resonance imaging (fMRI) findings have suggested a neural network for the processing of threatening stimuli, with increased activation in the prefrontal cortex, insula, and posterior cingulated cortex, when subjects were exposed to phobia-sensitive words (eg, spider phobia), compared with subjects without phobias. (See Etiology, Pathophysiology.)
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The specific nature of anxiety associated with specific phobia is felt to be associated with an increase in tonic cardiac vagal tone, manifested by an increase in heart rate, which is considered to be greater than that in other anxiety disorders.
These responses are mediated by the autonomic nerve system, or more specifically, by its parasympathetic branch. The vagus nerve attenuates the sympathetic nervous system output and is key to responsiveness to environmental cues.
Children with specific phobias are felt to display a greater degree of response to perceived threats, although they do not demonstrate an increase in anticipatory responsiveness. (See History.) However, this physiologic change is not the same with all specific phobias, because different specific phobias have been associated with differences in cardiac vagal tone.
Assessment of specific phobia generally consists of structured or semistructured interviews by the practitioner with the child and his or her parents. Various rating scales are also available to assess anxiety disorders. (See Workup.)
Numerous theories about the etiology of specific phobias have been offered. Psychoanalytic theory offered an early explanation, although it is no longer supported.
Many other theories have been proposed, including learning theories, explanations encompassing environmental influences, and theories regarding genetic factors. (Genetic and environmental factors are generally acknowledged to influence behavior, including anxiety disorders in general and specific phobias in particular.) It has also been proposed that a combination of these factors gives rise to specific phobias.
In the classic conditioning theory, it is believed that a previous neutral stimulus is paired with an aversive stimulus that elicits a strong fear or emotional response. Often, adults in the child's life may be unaware of the aversive episode. Some believe this learning may be direct or vicarious, which entails witnessing an event involving another person that elicits fear.
The operant conditioning theory holds that parents may inadvertently reinforce a child’s phobic behavior by providing the child with increased amounts of social attention surrounding the avoidant behavior. In young children, familial influences have been reported to affect comorbidity between specific phobia and separation anxiety and between specific phobia and social phobia. These influences are felt to reflect shared environmental influences more than genetic factors. Learning and modeling, as well as parent-child interactions, have been proposed as possible explanations.
Because learning theories are not felt to adequately explain the development and persistence of phobias, attention has been focused on the role of cognition. Children with anxiety disorders are more likely to display distorted and maladaptive thoughts, although the extent to which these negative thoughts are causes or consequences of their fears is unclear.
A familial component of specific phobia is often observed, although the type of specific phobia is usually different.
Genetic factors are felt to contribute to specific phobia. Genetic effects on early onset disorders have been reported to be more substantial than environmental factors. A recent twin study of adolescents found that genetic factors appear to nonspecifically increase risk for all the pediatric anxiety disorders including pediatric specific phobia.[1]
Increased fears and phobias have been identified in children of parents with major depressive disorder and anxiety, although they have not been found to be associated with parents with major depressive disorder without anxiety.[2]
Avoidance of new foods has been found to be highly heritable in children aged 8-11 years, although less than one fourth of children with this presentation are also believed to be influenced by nonshared environmental factors.[3]
Constitutional factors and individual experiences increase the risk for developing anxiety disorders.
Manifestations of constitutional factors may be apparent in individual differences in responsiveness to environmental events. A sudden, loud sound elicits a range of emotional responses in different children, some of which are the result of biological differences.
Children who demonstrate a stable behavioral inhibition (becoming excessively distressed and withdrawn in novel situations) from infancy through childhood have higher rates of anxiety disorders than do children who are not consistently inhibited. These findings suggest that childhood behavioral inhibition may be a risk factor for developing anxiety disorders.
Personality is felt to be heritable.
The National Institute of Mental Health (NIMH) estimates that 5-12% of Americans have phobias; specific phobias affect approximately 6 million Americans.[4] Approximately 7-9% of children have been estimated to have specific phobia.
The National Comorbidity Survey-Adolescent Supplement estimated the lifetime prevalence of specific phobia to be 22.1% for adolescent girls and 16.7% in boys. However, only 0.6% of adolescents were rated as severely impaired by a specific phobia.[5]
No significant differences in the incidence of specific phobias have been noted between whites, blacks, or Latinos.
No conclusive evidence links socioeconomic status with specific phobia.
The prevalence rates and types of phobias vary among various cultural and ethnic groups. The overall reported prevalence rates in children in New Zealand, Puerto Rico, Switzerland, and Germany are low.
Females may be at higher risk for developing specific phobia than males. The sex difference is less notable for certain specific phobias, such as a fear of heights.
The mean age of onset of specific phobia depends on the type of phobia that develops. Animal, blood, and storms and water-specific phobias typically develop in early childhood. Height specific phobia develops in teenagers. Situational specific phobias (eg, claustrophobia) typically develop during the late teenage years and early third decade of life.
Fears and phobias are common in young children. Referral rates tend to increase in mid-to-late childhood and early adolescence. The peak age for referral of children diagnosed with specific phobia is 10-13 years, with the average age of symptom onset at approximately 8 years.
The prognosis for specific phobia is good with appropriate treatment. Poor response to therapy may be secondary to poor compliance, motivation, or understanding of treatment procedures. Interpersonal factors may also interfere with treatment results.
The presence of more than one specific phobia (eg, spider and needle) is associated with early age of onset, increased anxiety severity, and impairment. Additionally, children and adolescents with more than one type of phobic stimulus have higher rates of psychiatric comorbidity.[6]
In some instances, natural environmental contingencies may extinguish a fear. Specific phobias in children generally attenuate over time, although they may persist into adulthood. In contrast, specific phobias that appear in adolescents and adults tend to persist, with only approximately 20% of these cases resolving without intervention.
Patients with specific phobia may be at increased risk for future anxiety disorders.
Parents may be expected to assist in the therapeutic process for children with specific phobia.
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Behaviorally, phobias manifest as the need to escape or avoid the feared object or situation. The fear may be expressed somatically by tremor, feeling faint or actually fainting, nausea, diaphoresis, rapid heart rate, increased blood pressure, and feelings of panic. Children may present with crying, tantrums, clinging, or immobilization.
Parents of children with anxiety disorders typically have a higher than average incidence of anxiety disorders in their histories. Similarly, children whose parents have a specific phobia display a higher rate of specific phobia than do control subjects.
Children with anxiety disorders are more likely to display distorted and maladaptive thoughts, but whether these negative thoughts are causes or consequences of their fears is unclear.
Specific phobia may be associated with problems with peers, family, and school, difficulties that may negatively affect self-esteem. Unlike adults, children may not acknowledge that their fear is excessive or unreasonable. (See Workup.)
Self-medication by adults with alcohol and drugs, which has been reported with some anxiety disorders, is not commonly reported in patients with specific phobia.[7]
Physical examination may be helpful in documenting evidence of autonomic hyperactivity common in specific phobia. Signs of autonomic hyperactivity may include increased blood pressure, increased heart rate, diaphoresis with sweating palms, or mydriasis. However, autonomic hyperactivity may be sporadic and not present during the physical examination. Physical symptoms such as headaches or stomachaches are commonly seen in children with anxiety disorders, including specific phobias.
Physicians may elect to use a targeted physical examination to aid in ruling out a physical cause for prominent specific physical complaints in individual cases.
Fears and phobias are common in young children; thus, preschool children are rarely referred and diagnosed as phobic. Common fears of childhood need to be distinguished from specific phobia, as the latter is irrational, interferes more with daily routines, and leads to maladaptive behaviors.
Assessments generally consist of structured or semistructured interviews by the practitioner with the child and his or her parents. Various rating scales are also available to assess anxiety disorders.
Diagnostic criteria for specific phobia is found in the Diagnostic and Statistical Manual of Mental Disorders,FifthEdition (DSM-5).[8] This revision made no significant criteria changes for the diagnosis of pediatric specific phobia.
The specific DSM-5 criteria for specific phobia are as follows:[8]
The following specifiers are used, according to the phobic stimulus present:[8]
Behavioral therapy, which includes exposure therapy and cognitive behavioral therapy, is the first-line treatment. However, pharmacologic treatment, administered in combination with behavioral therapy, may provide some therapeutic benefit.
Specific phobia alone does not require inpatient treatment.
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In this treatment technique, the patient is repeatedly exposed to the feared stimulus until the anxiety response it elicits is habituated. One-session treatment lasting as long as 3 hours and combining exposure therapy in a fear hierarchy with participant modeling, cognitive components, and reinforcement, is a promising form of treatment in patients with specific phobias.[9]
A gradual exposure program, especially for the treatment of children, is developed, in which the least-feared stimulus in a fear hierarchy is presented first, followed sequentially over time (in a graduated manner) by the more feared stimuli in the hierarchy. Fear hierarchies are created by the behavior therapist in collaboration with the child and parents.
Exposure to the feared stimulus may be conducted in real-life or imaginary contexts, in which the child is requested to visualize the feared object or situation. The longer the child is exposed to the aversive stimulus, the greater the likelihood that habituation occurs and anxiety decreases.
These procedures are used when the therapist determines that the maintenance of the phobia may have a significant cognitive component. Procedures may include those in which the child is taught skills for contingency management, modeling management, and self-control. Applied tension and relaxation may be introduced, as well as improvement of specific skill deficits.
No significant differences in outcome have been reported comparing individual cognitive behavioral therapy with group cognitive behavioral therapy, with improvements noted in both types of therapeutic settings.[10, 11]
This type of therapy is generally felt to have limited use in the treatment of specific phobia, with behavioral therapy being the main route of intervention. In some instances, selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, sertraline, fluvoxamine, citalopram, and paroxetine, have been reported to be effective. SSRIs have been used as adjunctive therapy, because patients may have coexisting anxiety disorders. (See Medication.)
Virtual reality exposure therapy, using a computer to provide graded exposures, has been reported.[12, 13] However, use of this technology has not been well studied in children.
Psychotherapy is not generally used to treat the specific phobia. However, the presence of an increasingly complex or disabling profile may require individual and family psychotherapy.
Consultation with a child behavioral psychologist and/or child and adolescent psychiatrist may be necessary.
Close, frequent monitoring of any patient treated with psychotropic medications is imperative.
Although behavioral therapy is the main route of intervention for specific phobias that interferes with functioning, case reports have documented improvement of symptoms with the use of selective serotonin reuptake inhibitors (SSRIs).
Benzodiazepines have not been shown to be effective and play a limited role for most severe, chronic specific phobias. However, they may be helpful in specific situations in which intense fear as a result of exposure to a specific phobic stimulus cannot be avoided. For example, in an adolescent with severe claustrophobia who has an urgent need for a head MRI, a course of behavioral therapy is not feasible owing to time constraints and SSRI drugs would not be helpful. In this setting, pre-MRI scan treatment with a benzodiazepine may be quite helpful.
Clinical Context: Fluoxetine selectively inhibits presynaptic serotonin reuptake with minimal or no effect in the reuptake of norepinephrine or dopamine. Selective serotonin inhibitors such as fluoxetine have less sedation, cardiovascular, and anticholinergic effects than the tricyclic antidepressants.
Clinical Context: Citalopram enhances serotonin activity by selective reuptake inhibition at the neuronal membrane. Citalopram is FDA approved for depression but has been used for the treatment of anxiety disorders. SSRIs are the antidepressants of choice because of their minimal anticholinergic effects.
Clinical Context: Escitalopram is an SSRI and S-enantiomer of citalopram. It is used for the treatment of depression and has been used to treat other anxiety disorders. Its mechanism of action is thought to be potentiation of serotonergic activity in the CNS, resulting from inhibition of CNS neuronal reuptake of serotonin.
Clinical Context: Fluvoxamine enhances serotonin activity due to selective reuptake inhibition at neuronal membrane. It does not significantly bind to alpha-adrenergic, histamine, or cholinergic receptors and thus has fewer side effects than tricyclic antidepressants.
It is FDA-approved for obsessive-compulsive disorder in children (8-17 y) and adults. It may also be helpful for the treatment of other anxiety disorders.
Clinical Context: Paroxetine is a potent selective inhibitor of neuronal serotonin reuptake. It also has a weak effect on norepinephrine and dopamine neuronal reuptake. It is FDA approved for panic disorder, depression, social anxiety disorder, and obsessive-compulsive disorder. It may also be helpful for other anxiety disorders..
Clinical Context: Sertraline is a selective serotonin inhibitor that is FDA approved for panic disorder, posttraumatic stress disorder, social anxiety, and obsessive-compulsive disorder. Sertraline may also be helpful for the treatment of anxiety disorders.
These antidepressant agents have been used as antianxiety medications to treat such conditions as panic disorders (with or without agoraphobia), generalized anxiety disorders, obsessive-compulsive disorders, and specific phobias.
SSRIs are now strongly preferred over other classes of antidepressants owing to their clinical efficacy and tolerability. The adverse effect profile of SSRIs is less prominent, with improved compliance. These agents also do not have the cardiac arrhythmia risk associated with tricyclic antidepressants (tertiary and secondary amine). Arrhythmia risk is especially pertinent in accidental and intentional overdose. The suicide risk must always be considered when a child or adolescent with mood disorder is treated with any psychotropic medication, including SSRIs.
Physicians are advised to be aware of the following information and to use appropriate caution when considering treatment with SSRIs in the pediatric population.
In December 2003, the UK Medicines and Healthcare Products Regulatory Agency (MHRA) issued an advisory that most SSRIs are not suitable for use in persons younger than 18 years for treatment of "depressive illness." After review, this agency decided that the risks to pediatric patients outweigh the benefits of treatment with SSRIs, except fluoxetine (Prozac), which appears to have a positive risk-benefit ratio in the treatment of depressive illness in patients younger than 18 years.
In October 2003, the US Food and Drug Administration (FDA) issued a public health advisory regarding reports of suicidality in pediatric patients being treated with antidepressant medications for major depressive disorder. This advisory reported suicidality (ideation and attempts) in clinical trials of various antidepressant drugs in pediatric patients. The FDA has asked that additional studies be performed, because suicidality occurred in treated and untreated patients with major depression and thus could not be definitively linked to drug treatment.
A 2006 study did not support an increase in suicide risk or attempts after antidepressant medication was started or a higher risk with the newer types of antidepressant medication.[14] The study evaluated records of more than 65,000 children and adults treated for depression over a 10-year period.
Despite the results of this investigation, close, frequent monitoring of any patient treated with psychotropic medications remains imperative.