When Albert was 6, a dog lunged and barked at him. Since then, he has been very afraid that all dogs will attack and kill him. As a result, Albert goes out of his way to avoid dogs at all costs and believes that he is unable to handle being around a dog. When he sees a dog, he becomes very distressed and starts crying.

Eliza, 10 years old, is very fearful of thunderstorms. She is afraid that the storm will result in a natural disaster that will destroy her home and hurt her family members. Eliza constantly checks the weather; if there is even a chance of a thunderstorm, she refuses to go outside. Instead she hides under her bed, crying.

When Connor was 11, he got stuck in an elevator. Since then, he has been terrified of being in enclosed spaces, fearing that he will be trapped forever. When inside an enclosed space, Connor feels dizzy and panicked. He believes that the only way to manage his fear of enclosed spaces is to avoid them.

Signs and Symptoms of Specific Phobias

What do Albert, Eliza, and Connor have in common? Although each child is afraid of something different, they all display signs and symptoms of a specific phobia. Characterized by excessive fear or anxiety about a specific object or situation, specific phobias can be categorized into five subtypes: animal (dogs, snakes, spiders, etc.), natural environment (such as storms, water, and heights), situational (enclosed spaces, elevators, flying, etc.), blood-injection-injury (including seeing blood, needles, or shots), and other, which includes choking or vomiting, loud sounds, and costumed characters.1

In the cases above, the children are displaying symptoms of the three most common types of specific phobias in youth1: Albert shows signs of the animal subtype, Eliza shows symptoms of the natural environment subtype, and Connor is displaying signs of the situational subtype. In each case, they are displaying three of the key mechanisms that maintain their fear or anxiety: the probability bias, the cost bias, and a decreased self-efficacy to cope.

Probability Bias

The probability bias is when individuals overestimate the likelihood, or the probability, of something bad happening.2 For example, Connor believes that being in an enclosed space will always result in his being trapped in that space. Even though the likelihood that he will get trapped in an enclosed space does exist, it is unlikely that this will happen every time. This is how Connor overestimates the likelihood of the situation ending negatively.

Cost Bias

Connor also shows evidence of the cost bias, which is an overestimation of just how bad a negative consequence is, or its cost.2 For example, getting trapped in an enclosed space is distressing, of course, but Connor overestimates its negative consequence because he believes that he will stay trapped in an enclosed space forever. Connor overestimates the cost of the situation.

Decreased Self-Efficacy

Connor displays a decreased self-efficacy to cope with his fear of enclosed spaces. The term "self-efficacy" refers to the belief in one's ability to do something successfully.3 A decreased self-efficacy to cope refers to a decreased belief in one's abilities to cope with something successfully. In the case of Connor, this is evident in his repeated avoidance of enclosed spaces. Because he does not believe that he can manage his fear of enclosed spaces, he avoids them.

Similarities and Differences of Phobias

Albert, Eliza, and Connor are afraid of completely different things. But do their phobias differ in other ways, too? Overall, the mechanisms of maintaining or exacerbating symptoms for specific phobias are relatively similar. All subtypes are characterized by maladaptive beliefs and behaviors, including avoiding the feared object or situation.1 However, less research has examined the differences in the probability bias, cost bias, and self-efficacy to cope between specific phobia subtypes and over time as children develop. Such findings may provide further information on what clinicians who treat specific phobias in children and adolescents could target and when.

To address this, researchers at Virginia Tech and Stockholm University conducted a study of 251 American and Swedish children and adolescents (ages 7 to 15) who had received formal diagnoses of one of the three most common subtypes of specific phobia in this age group: animal, natural environment, and situational.4 All study participants indicated three beliefs related to their specific phobia (example: I will be trapped in an enclosed space forever). Each then rated how likely it would be for their feared belief to occur (probability bias) and how bad it would be for their feared belief to occur (cost bias). They also rated their ability to cope if their feared belief were to actually occur (self-efficacy).

The results indicated no significant differences in cost bias and self-efficacy between the three specific phobia types. All three specific phobia groups overestimated the cost bias and underestimated their ability to cope relatively equally. The groups differed only in their probability estimates of their feared beliefs occurring. More specifically, those diagnosed with specific phobias of animals were more likely to rate their feared beliefs as more likely to occur than those diagnosed with natural environment or situational specific phobias.

The results also indicated that age had a significant effect on cost bias. The older children were more likely to rate their feared beliefs as having a greater cost bias, when compared to the younger children. Regardless of the type of specific phobia, older youth tended to rate the negative consequences of their feared beliefs occurring as worse. The researchers hypothesized that this may be due to the increased cognitive capacity to understand consequences that comes with age.

Treating Specific Phobias in Youth

Does this mean that older children and those with specific phobias of animals will be less responsive to treatment? Absolutely not. In fact, the researchers conducted a second study in which the same participants completed a single-session treatment.4 A three-hour therapy session based on cognitive behavioral therapy (CBT), this treatment involved psychoeducation about specific phobias, challenging participants' feared beliefs, and exposures in which participants were exposed to their feared situations and stimuli.

The results showed that decreases in the cost and probability biases and increases in self-efficacy were associated with better treatment outcomes. They also indicated that all three subtypes displayed a relatively equal decrease in the cost and probability biases, as well as an increase in self-efficacy. And there were no significant relationship between the age of participants and treatment outcome. Being older was not significantly related to changes in cost bias, probability bias, and self-efficacy following treatment. There is no suggestion from this study that older children are less responsive to treatment.

CBT, a Positive Impact on Specific Phobias

So, can a single session of CBT effectively treat specific phobias for all children and adolescents? Not exactly. The treatment provided in the study wasn't simply a single session of CBT, but rather an in-depth assessment followed by a three-hour session that combined the core elements of multiple sessions of CBT (psychoeducation, cognitive restructuring and challenging maladaptive beliefs, and exposure). The sessions were specifically tailored to address each participant's individual feared beliefs. This treatment is not the same as going to a CBT therapist for just one session.

This study was conducted on animal, natural environment, and situational specific phobia subtypes only. These are the most common in youth, but they are also qualitatively different from blood-injection-injury or the choking or vomiting types, which are more focused on physical and somatic symptoms (such as dizziness or fainting) rather than on catastrophizing beliefs. Further research is necessary to examine these findings in all types of specific phobias. Because the study was primarily conducted on youth racially identifying as white and middle class, the results may not apply to other racial, ethnic, or socioeconomic youth who may have different fear beliefs and specific phobias. However, despite such limitations, the results do seem to indicate that although specific phobia types have different degrees and patterns of probability bias, cost bias, and self-efficacy, CBT can have a significant positive impact on at least three of these specific phobia types.


Date of original publication:


1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders: DSM-5. Washington, DC: American Psychiatric Association.

2. Boyce, P., Harris, A., Drobny, J., Lampe, L., Starcevic, V., & Bryant, R. (Eds.). (2015). The Sydney handbook of anxiety disorders: A guide to the symptoms, causes, and treatments of anxiety disorders. Sydney, Australia: The University of Sydney.

3. Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84, 191-215.

4. Ollendick, T. H., Ost, L., Ryan, S. M., Capriola, N. N., Reuterskiold, L. R. (2017). Harm beliefs and coping expectancies in youth with specific phobias. Behaviour Research and Therapy, 91, 51-57.