Obsessive-compulsive disorder

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Obsessive-compulsive disorder

Psychological disorders

Bipolar and related disorders

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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


Obsessive-compulsive disorder


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USMLE® Step 1 questions

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High Yield Notes

3 pages


Obsessive-compulsive disorder

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USMLE® Step 1 style questions USMLE

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A 17-year-old girl is brought to the physician by her mother due to recent hair loss. The mother tells the physician that she has noticed a gradual loss of hair on her daughter’s head over the past 3 months. The daughter is embarrassed by her appearance and always tries to cover her hair with a hat. When interviewed alone, the patient tells the physician she sometimes plucks hair off her head. She has tried multiple times to stop this behavior, but she has been unable to do so. She adds that she feels excessive stress before hair pulling that is resolved when she pulls her hair. Which of the following will be most likely seen on microscopic examination of the hair follicles and the scalp of this patient?

External References

First Aid








Clomipramine p. 599

obsessive-compulsive disorder p. 586

Cognitive behavioral therapy (CBT) p. 580

obsessive-compulsive disorder p. 586

Obsessive-compulsive disorder (OCD) p. 586

antipsychotic drugs for p. 597

atypical antipsychotics for p. 597

drug therapy for p. 596

SSRIs for p. 599

Tourette syndrome and p. 580

tricyclic antidepressants for p. 599

venlafaxine for p. 599

SSRIs (selective serotonin reuptake inhibitors) p. 599

obsessive-compulsive disorder p. 586

Tourette syndrome p. 580

obsessive-compulsive disorder and p. 586


Content Reviewers

Double-checking things is a pretty common human behavior, like—did I shut the garage-door? Better double-check. How about locking the front door? Double-check. Gas-stove and oven off? Double-check. We all do it.

But what if you feel compelled to triple-check it, or even quadruple check it, or quintuple check it even, then it might be considered an obsession.

Now, what if you have to do a certain ritual with the gas-stove and oven before leaving the home each time, like: make sure the gas-stove is off, wipe down the gas stove to clean it, double-check that the burners are off, make sure the oven is off, wipe down the oven to clean it, and then open the oven door to make sure no heat is coming out, and then leave the house.

Then that might be a compulsion.

Obsessive-compulsive disorder, or OCD, is a specific type of anxiety disorder characterized by these obsessions or compulsions.

Obsessions are recurrent and intrusive thoughts that are typically unwanted and tough to get out of your brain.

These unwanted thoughts like, “My house is unsafe!” cause anxiety, and usually they lead to compulsions, which are actions that might be performed to try and reduce the anxiety associated with obsessions.

As you might imagine, these thoughts and rituals can have a serious impact on someone’s daily life.

OCD affects around 3% of the population, and usually starts in childhood or in the teen years.

Celebrities like David Beckham and Howie Mandel are known to be affected by OCD.

A more severe example is that of Howard Hughes, business tycoon, entrepreneur, and inspiration for the movie Citizen Kane, who was affected by relatively incapacitating OCD later in his life.

A very common compulsion is cleaning, which often stems from an obsession with germs or contamination.

Another common compulsion is checking: people who have this compulsion usually have an associated obsession that something’s unsafe, so they’ll check to make sure that something’s definitely safe, like making sure the door’s locked by unlocking and re-locking, perhaps several times.

More generally, repeating is a compulsion on its own; this is where an action or phrase is repeated several times, and usually because the repeater believes that if it’s not, something bad will happen.

Sometimes patients might feel compelled to order and arrange things, because when they’re out of order, it causes anxiety and discomfort.

Finally, mental rituals are also obsessions; these are often done to try and neutralize intrusive or “bad” thoughts.

People engaging in mental rituals might try and call up specific words or phrases they think are “good” thoughts to try and replace the “bad” thoughts.


Obsessive-compulsive disorder (OCD) is a mental health disorder characterized by repetitive thoughts and behaviors, which a person feels compelled to perform, to a level that interferes with a person's daily life, work, and relationships. Examples include concerns about contamination, leading to repeated hand washing, an exaggerated need for symmetry or exactness, etc. Treatment may involve psychotherapy like cognitive-behavioral therapy, medications like selective serotonin reuptake inhibitors, or both.


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