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Psychological disorders

Bipolar and related disorders

Bipolar disorder

Feeding and eating disorders

Anorexia nervosa

Bulimia nervosa

Medication-induced movement disorders and other adverse effects of medication

Neuroleptic malignant syndrome

Serotonin syndrome

Somatic symptom and related disorders

Factitious disorder

Somatic symptom disorder

Trauma and stressor-related disorders; Abuse

Physical and sexual abuse

Post-traumatic stress disorder




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USMLE® Step 1 questions

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High Yield Notes

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USMLE® Step 1 style questions USMLE

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A 30-year-old woman comes to the physician because she has become afraid to leave the house. The patient used to take the train to work every day, but she has experienced increasing anxiety about traveling in an enclosed space surrounded by people. Seven months ago, the patient had a panic attack in a public train station, and she reports feeling “terrified that might happen again.” Ever since that episode, the patient has avoided using public transportation, and she requested to work her job fully remote so that she no longer needs to leave her home. She has also started to avoid other public places where large crowds may be present, which has resulted in her no longer attending her place of worship. She states that she feels safe if she “just stays in the house.” She was diagnosed with major depressive disorder five years ago and was treated successfully with sertraline. She no longer takes any medications. Which of the following is the most likely diagnosis in this patient?

External References

First Aid




Benzodiazepines p. 529

phobias p. 547

β -blockers p. 241

phobias p. 547

Cognitive behavioral therapy (CBT) p. 541

phobias p. 547

MAO inhibitors p. 559

phobias p. 547

Phobias p. 546, 547

SSRIs (selective serotonin reuptake inhibitors) p. 559

phobias p. 547

Venlafaxine p. 559

phobias p. 547


Content Reviewers

Everybody, whether they like to admit it or not, has fears and gets anxious about certain things, whether it be a spider crawling on the ground or speaking in front of large groups of people.

In most cases though, people cope with those fears and confront them.

A phobia is the most extreme type of fear.

Someone with a phobia will go to great lengths to avoid being exposed to the fear or perceived danger, even if there’s no actual risk or danger, and people often feel powerless against it.

Phobias are considered the most common psychiatric disorder, affecting almost 10% of the population.

Phobias are extreme, often unreasonable and irrational fears of something, which could literally be anything, like: pyrophobia, the fear of fire; alektorophobia, the fear of chickens; triskaidekaphobia, the fear of the number 13; phobophobia, the fear of developing phobias; or even pinaciphobia, the fear of lists.

Unreasonable or irrational fears get in the way of daily routines, work, and relationships, because patients with phobias often do whatever they can to avoid the anxiety and terrifying feelings associated with the phobia.

For example, most people don’t necessarily enjoy the company of spiders, but they also don’t let this fear affect their social or daily life; like, even though I know there are spiders in the woods, I wouldn’t avoid a camping trip on account of the spiders.

Even if they love camping, somebody with arachnophobia—a fear of spiders—might refuse to go because they know there’s a possibility of seeing a spider in close quarters.

In this case the fear’s clearly interfering with their social life and relationship with friends, meaning it’s a phobia.

An irrational fear of an object or situation like this is called a specific phobia.

The DSM-5 splits these specific phobias into five categories: fear of animals, like arachnophobia or alektorophobia; fear of the natural environment, like thalassophobia (fear of the ocean) or nyctophobia (fear of darkness); fear of blood and needles, like hemophobia (fear of blood); situational fears like aviophobia (fear of flying); and finally, “other” fears, like coulrophobia (fear of clowns).

These specific phobias are one of three main types of phobias.


Phobias are extreme, often irrational fears that interfere with a person's ability to function in their daily lives. Such fears are typically associated with a specific object, situation, or activity. Particularly bad phobias can cause physical symptoms like sweating, trembling, and increases in heart rate. Common phobias include fear of heights (acrophobia), fear of closed-in spaces (claustrophobia), fear of flying (aviophobia), fear of animals (zoophobia), and fear of social situations (social phobia). Managing phobias can require psychotherapy, particularly cognitive-behavioral therapy


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  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "Diagnostic and Statistical Manual of Mental Disorders (DSM-5 )" American Psychiatric Assoc Pub (2013)
  5. "Mechanisms of fear extinction" Molecular Psychiatry (2006)
  6. "Why do some individuals develop social phobia? A review with emphasis on the neurobiological influences" Nordic Journal of Psychiatry (2004)

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