View source for WBR0094

 {{WBRQuestion
|QuestionAuthor=Gonzalo Romero (Reviewed by  {{YD}} and  {{Rim}})
|ExamType=USMLE Step 1
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|MainCategory=Behavioral Science/Psychiatry, Pharmacology
|SubCategory=General Principles
|Prompt=A 25-year-old woman complains of generalized fatigue for the past 8 months. The patient reports she is generally unhappy and lacks motivation at work. She believes her co-workers reject her and admits she does not have any friends. She spends most of her time at home sleeping. When she wakes up, she is either watching TV or eating fast food. The patient also mentions that she feels an unusual sensation of heaviness in her arms and legs that makes it difficult for her to get out of bed sometimes. Upon further questioning, she denies suicidal or homicidal thoughts or feelings of worthlessness. The physician prescribes a pharmacologic agent to relieve the patient's symptoms. Which of the following is the mechanism of action of the drug the patient is receiving?
|Explanation=Atypical depression is a common subset of major depression that commonly affects young women. It is characterized by hypersomnia, weight gain, and emotional lability and rejection sensitivity. It is also associated with leaden paralysis or a heavy feeling in the arms and legs. Women are two to three times more likely to be affected with atypical depression than men. The course is often chronic and unrelenting, making treatment difficult. Unlike typical depression, which is characterized by anhedonia, weight gain, generally "down" mood, and feeling of guilt, symptoms of patients with atypical depression may improve with some activities and do not usually include guilt sensation or suicidal/homicidal ideations.

The treatment of choice for atypical depression is a [[monoamine oxidase inhibitor]] (MAOi), which inhibits [[5-HT]], [[norepinephrine]], and [[dopamine]] metabolism. MAO is a ubiquitous enzyme present in mitochondria. The enzyme exists in 2 forms: A and B. MAO inhibitors act by inhibiting the ubiquitous enzyme monoamine oxidase, which usually deaminates serotonin, norepinephrine, dopamine, and tyramine. Not only do MAO inhibitors provide a good therapeutic option for patients with atypical depression, but also they play a role in the diagnosis. The diagnosis of atypical depression is usually confirmed when good response to MAO inhibitors is observed. [[MAO inhibitor]]s include [[phenelzine]], [[tranylcypromine]], [[isocarboxacid]], and [[selegiline]]. Selegiline is considered a selective MAO-B inhibitor. The most important side effects of [[MAO inhibitor]]s are [[hypertensive crises]] when combined with [[tyramine]], a compound found in cheese and wine. MAO inhibitors are also associated with serotonin syndrome when administered in excess or in combination with other medications that increase the availability of serotonin, such as SSRI, TCA, meperidine, and dextromethorphan.
|AnswerA=Serotonin reuptake inhibitor
|AnswerAExp=[[Selective serotonin reuptake inhibitors]] ([[SSRIs]]) include [[paroxetine]], [[sertraline]], [[citalopram]], and [[fluoxetine]]. They are prescribed for patients with [[major depression]], [[generalized anxiety disorder]], [[bulimia nervosa]], [[social phobia]], [[OCD]], and [[PTSD]].
|AnswerB=Norepinephrine reuptake inhibitor
|AnswerBExp=[[Maprotiline]] is an atypical antidepressant which blocks [[norepinephrine]] reuptake. Because it is commonly associated with sedation with early doses, it may be helpful among depressed patients with agitation or suicidal risk.
|AnswerC=Serotonin receptor agonist
|AnswerCExp=[[Buspirone]], which is prescribed for patients with generalized anxiety disorder, stimulates [[serotonin]] (5-HT1a) receptors. Nootably, it is not associated with [[sedation]], [[addiction]] or [[tolerance]].
|AnswerD=Alpha-2 receptor antagonist
|AnswerDExp=[[Mirtazapine]] is an atypical antidepressant. It blocks alpha-2 receptors in the presynaptic neurons and increases the release of [[norepinephrine]] and [[serotonin]]. It causes [[sedation]] and therefore can be prescribed for depressed patients with [[insomnia]]. It might also cause an increase in appetite with possible weight gain.
|AnswerE=Serotonin, norepinephrine, and dopamine metabolism inhibitor
|AnswerEExp=Monoamine oxidase inhibitors (MAOi) are prescribed for patients with atypical depression. MAOi act by inhibiting the ubiquitous enzyme monoamine oxidase, which usually deaminates serotonin, norepinephrine, dopamine, and tyramine.
|EducationalObjectives=[[Atypical depression]] is characterized by mood reactivity, [[hypersomnia]], and [[weight gain]]. It is also associated with leaden paralysis, defined as a heaviness in the arms and legs. The treatment of choice is a [[MAO inhibitor]], which inhibits [[5-HT]], [[norepinephrine]], and [[dopamine]] metabolism.
|References=Pae CU, Tharwani H, Marks DM, Masand PS, Patkar AA. Atypical depression: a comprehensive review. CNS Drugs. 2009;23(12):1023-37.<br>
First Aid 2014 page 507
|RightAnswer=E
|WBRKeyword=Atypical depression, Depression, Psychiatry, MOI, Monoamine oxidase inhibitor
|Approved=Yes
}}