How many practice questions should I do for the psychiatry shelf?

For a standard 4- to 6-week psychiatry clerkship, aim for 400 to 500 dedicated practice questions alongside 3 to 4 official NBME Clinical Science Subject Examination forms. Psychiatry is notoriously conceptual: while the question vignettes may seem deceptively conversational, the distractor answer choices require meticulous precision regarding DSM-5-TR time criteria (e.g., 2 weeks for MDD, 1 month for schizophrenia symptoms, 6 months for GAD) and subtle psychopharmacologic receptor profiles. Completing 15 to 20 questions daily with active review of missed differentials will secure honors.

How do I differentiate Serotonin Syndrome from Neuroleptic Malignant Syndrome on test questions?

Remember the classic physical examination discriminators: Serotonin Syndrome (caused by SSRIs, SNRIs, MAOIs, tramadol, linezolid, triptans, or MDMA) is characterized by neuromuscular hyperreactivity—hyperreflexia, clonus (ocular, spontaneous, or inducible), shivering, and tremor, alongside diarrhea, mydriasis, and hyperthermia; treat with cyproheptadine. Neuroleptic Malignant Syndrome (caused by dopamine antagonists/antipsychotics) is characterized by severe lead-pipe muscle rigidity, hyporeflexia (or normal reflexes), bradykinesia, profound hyperthermia, extreme autonomic instability, and massively elevated serum creatine kinase; treat with bromocriptine or dantrolene.

What are the classic psychotic disorder diagnostic timelines?

DSM-5-TR psychotic disorders are categorized strictly by symptom duration: Brief Psychotic Disorder lasts from 1 day to less than 1 month, followed by full return to premorbid functioning (often triggered by severe psychosocial stress); Schizophreniform Disorder lasts from 1 month to less than 6 months; and Schizophrenia requires continuous signs of disturbance for at least 6 months, including at least 1 month of active-phase symptoms (delusions, hallucinations, disorganized speech). Schizoaffective Disorder requires a lifetime major mood episode concurrent with psychotic symptoms, plus at least 2 weeks of delusions or hallucinations in the complete absence of major mood symptoms.

What is the passing score and honors cutoff for the psychiatry shelf?

National equating metrics are provided by the NBME, but grading criteria are established locally by each medical school’s curriculum committee. Passing usually corresponds to approximately the 5th to 10th percentile (typically an Equated Percent Correct or scaled score around 64–67), while earning an Honors grade typically requires scoring at or above the 70th to 85th percentile (often a scaled score between 80 and 86). Check your clerkship syllabus during orientation to verify your school’s exact grading benchmarks.

How do I choose between first- and second-generation antipsychotics on the shelf?

Second-generation (atypical) antipsychotics (such as aripiprazole, quetiapine, risperidone, olanzapine) are generally first-line for schizophrenia and bipolar mania due to significantly lower rates of extrapyramidal symptoms and tardive dyskinesia compared to high-potency first-generation agents like haloperidol. However, atypicals require monitoring for metabolic syndrome (weight gain, dyslipidemia, hyperglycemia), with olanzapine and clozapine carrying the greatest metabolic risk. Clozapine is strictly reserved for treatment-resistant schizophrenia (failure of ≥ 2 antipsychotics) or persistent suicidal behavior, and mandates absolute neutrophil count (ANC) monitoring due to agranulocytosis risk.

How is the Psychiatry shelf different from Step 2 CK behavioral health questions?

Step 2 CK emphasizes general screening, substance intoxication/withdrawal presentations, and common outpatient depression and anxiety titration. The NBME Psychiatry Subject Examination requires deeper diagnostic granularity: distinguishing subtle personality disorders (e.g., schizoid vs. avoidant, schizotypal vs. schizophrenia), managing refractory acute psych emergencies (severe catatonia requiring lorazepam challenge or electroconvulsive therapy), and navigating complex psychiatric legal/ethical dilemmas (involuntary hospitalization criteria vs. informed consent capacity in chronic psychotic illness).

Psychiatry Shelf Practice Questions: DSM-5-TR & Clerkship Strategy

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These psychiatry shelf practice questions focus on DSM-5-TR diagnostic timelines, emergency toxidrome discrimination, and psychopharmacologic titration. Free includes 10 questions per day with the diagnostic; Pro is $180/yr ($15/mo billed yearly or $25/mo monthly).

By Jed Whetten, MD Candidate, University of Arizona College of Medicine – Phoenix.

Launch Psychiatry Diagnostic

Worked Clinical Vignettes

Work through authentic cases from the Penziv item bank. Each question illustrates a high-yield clinical dilemma tested on the NBME Psychiatry Subject Examination.

Case 1: Dementia with Lewy Bodies vs. Alzheimer & Parkinson Differentiation

A 71-year-old man is brought to the outpatient psychiatric clinic by his wife due to progressive cognitive decline and recurrent visual hallucinations over the past 8 months. His wife reports that he frequently sees unfamiliar children and animals sitting quietly in their living room, and his attention and alertness fluctuate markedly from day to day. Over the past 3 months, he has developed progressive slowness in his movements, stiffness in his arms, and a soft voice; she also notes that he has violently acted out vivid dreams during sleep for the past 2 years. He takes no prescribed medications and has no prior history of psychiatric illness. Blood pressure is 128/78 mm Hg, pulse is 72/min, and respirations are 14/min. Mental status examination reveals fluctuating attention during serial subtraction tasks and pronounced impairment on clock-drawing, while non-contrast head CT demonstrates mild diffuse cerebral atrophy without focal infarction or ventriculomegaly. Neurologic examination demonstrates masked facies, mild bilateral resting hand tremor, cogwheel rigidity in both upper extremities, and a slow, shuffling gait. Which of the following is the most likely diagnosis?

Alzheimer disease

Normal pressure hydrocephalus

Vascular dementia

Dementia with Lewy bodies— Correct Answer

Frontotemporal dementia

Parkinson disease dementia

Explanation:

Dementia with Lewy bodies is characterized clinically by the tetrad of fluctuating cognitive impairment, detailed visual hallucinations, REM sleep behavior disorder, and spontaneous parkinsonism presenting within 1 year of cognitive decline.

Clinical recognition: The patient presents with progressive dementia characterized by prominent visuospatial and executive deficits (impaired clock-drawing test), dramatic fluctuations in alertness and attention, recurrent well-formed visual hallucinations, dream-enactment behavior (REM sleep behavior disorder), and parkinsonian motor signs (resting tremor, cogwheel rigidity, masked facies, shuffling gait).
Diagnostic criteria: According to DSM-5 criteria, probable dementia with Lewy bodies requires dementia plus at least two core clinical features: fluctuating cognition, recurrent detailed visual hallucinations, REM sleep behavior disorder, and spontaneous motor features of parkinsonism. When cognitive impairment occurs prior to or within one year of the onset of motor symptoms (the "one-year rule"), dementia with Lewy bodies is diagnosed rather than Parkinson disease dementia.
Pathophysiologic mechanism: The condition is caused by widespread neuronal accumulation of insoluble α-synuclein aggregates that form eosinophilic cytoplasmic inclusions (Lewy bodies) in both subcortical nuclei (substantia nigra) and cortical regions (limbic and neocortical areas).

Dementia with Lewy bodies is diagnosed when dementia occurs before, concurrently with, or within 1 year of the onset of parkinsonian motor signs.
Key clinical features include vivid visual hallucinations ("ha-Lewy-cinations"), fluctuating attention/alertness, REM sleep behavior disorder, and spontaneous parkinsonism.
The underlying pathology consists of α-synuclein inclusions (Lewy bodies) in cortical and brainstem neurons.

Case 2: Conduct Disorder Diagnostic Criteria in Adolescents

A 16-year-old boy is brought to the outpatient clinic by his parents for an evaluation mandated by his school district. Over the past 8 months, he has accumulated multiple unexcused absences, forged parental signatures on official documents, and was recently caught breaking into student lockers to steal and resell electronic devices. His parents also report that he intentionally set fire to a neighbor's detached storage shed following a dispute over parking. He has no significant past medical history and takes no medications. On mental status examination, he is alert and casually dressed, maintaining steady eye contact while speaking in a calm, dismissive tone. He displays a restricted affect and expresses no guilt or regret regarding the thefts or the fire, stating that his classmates were careless and the neighbor provoked him. Temperature is 36.8°C (98.2°F), pulse is 72/min, respirations are 14/min, and blood pressure is 118/74 mm Hg; physical examination and a urine toxicology screen are unremarkable. Which of the following is the most likely diagnosis?

Intermittent explosive disorder

Oppositional defiant disorder

Antisocial personality disorder

Conduct disorder— Correct Answer

Attention-deficit hyperactivity disorder

Disruptive mood dysregulation disorder

Explanation:

Conduct disorder is diagnosed in children and adolescents under 18 years of age who demonstrate a repetitive and persistent pattern of behavior that violates societal norms and the basic rights of others, including destruction of property, deceitfulness, theft, and serious rule violations.

The patient is a 16-year-old adolescent who exhibits deliberate destruction of property (intentional arson), deceitfulness and theft (breaking into lockers, reselling stolen electronics, forging signatures), and serious rule violations (truancy) over an 8-month period.
Furthermore, the patient displays callous-unemotional traits, specifically a lack of remorse or empathy, rationalizing his predatory behavior by blaming his victims.
According to DSM-5 criteria, these behaviors satisfy the criteria for conduct disorder; although these symptoms resemble antisocial personality disorder, an individual must be at least 18 years of age to receive an antisocial personality disorder diagnosis, making conduct disorder the correct diagnosis.

Conduct disorder is characterized by aggression toward people/animals, destruction of property (e.g., fire-setting), deceitfulness or theft, and serious rule violations in patients younger than 18 years.
Conduct disorder frequently carries a high risk of progressing to antisocial personality disorder once the patient reaches 18 years of age.

Case 3: Serotonin Syndrome Pharmacotherapy & Cyproheptadine Protocol

A 32-year-old woman is brought to the emergency department by her partner due to severe agitation, shivering, and confusion for the past 8 hours. The patient has a history of treatment-resistant major depressive disorder and migraine headaches. Two weeks ago, her psychiatrist initiated phenelzine after multiple failed trials of other antidepressants. Yesterday evening, she developed a severe migraine and took two doses of sumatriptan alongside an over-the-counter cough and cold syrup containing dextromethorphan. Temperature is 39.4 C (102.9 F), blood pressure is 172/98 mm Hg, pulse is 128/min, and respirations are 24/min. Physical examination reveals a restless, diaphoretic woman with bilateral mydriasis. Bowel sounds are hyperactive. Neurologic examination demonstrates moderate lower-extremity hypertonia, marked hyperreflexia (4+ patellar reflexes), and spontaneous bilateral ankle clonus and ocular clonus. Complete blood count, serum creatinine, and electrolyte levels are within normal limits. Despite receiving intravenous fluids and 8 mg of intravenous lorazepam, her agitation, fever, and clonus persist. Which of the following is the most appropriate next pharmacologic agent?

Cyproheptadine— Correct Answer

Bromocriptine

Physostigmine

Dantrolene

Flumazenil

Explanation:

Cyproheptadine is a first-generation antihistamine with potent serotonin 5-HT1A and 5-HT2A receptor antagonist properties, utilized as a specific antidote in moderate-to-severe serotonin syndrome unresponsive to supportive care and benzodiazepines.

Clinical recognition: The patient presents with the classic triad of serotonin syndrome (autonomic instability, neuromuscular excitability, and altered mental status) following the simultaneous ingestion of multiple serotonergic agents (phenelzine [monoamine oxidase inhibitor], sumatriptan [5-HT1B/1D agonist], and dextromethorphan [serotonin reuptake inhibitor]).
Key diagnostic signs: The presence of spontaneous clonus, hyperreflexia, hyperthermia, mydriasis, and diaphoresis satisfies the Hunter Serotonin Toxicity Criteria.
Therapeutic hierarchy: First-line therapy involves discontinuation of serotonergic agents, supportive care (cooling, hydration), and intravenous benzodiazepines for sedation and tremor control. When symptoms persist despite aggressive benzodiazepine therapy, cyproheptadine is indicated.

Serotonin syndrome is distinguished from neuroleptic malignant syndrome (NMS) by the presence of neuromuscular hyperactivity (hyperreflexia, clonus, ocular clonus) and hyperactive bowel sounds, whereas NMS features lead-pipe rigidity, hyporeflexia, and normal to sluggish bowel sounds.
Dextromethorphan, tramadol, meperidine, linezolid, and triptans possess potent serotonergic activity that can precipitate fatal toxicity when combined with MAOIs.

Case 4: Toxidrome Emergency: Serotonin Syndrome vs. Neuroleptic Malignant Syndrome

A 23-year-old man is brought to the emergency department by his roommate because of acute confusion, agitation, and sweating. The roommate notes that the patient has a history of major depressive disorder treated with sertraline. Two days ago, the patient developed a dry cough and runny nose and began taking maximum doses of over-the-counter dextromethorphan cold syrup. Temperature is 39.1°C (102.4°F), blood pressure is 168/96 mm Hg, pulse is 122/min, respirations are 24/min, and oxygen saturation is 98% on ambient air. Physical examination reveals an agitated, diaphoretic young man who is disoriented to time and place. Pupils are 6 mm bilaterally and reactive to light. Cardiopulmonary examination shows sinus tachycardia without murmurs. Abdominal examination reveals hyperactive bowel sounds. Neurological examination reveals bilateral ocular clonus, a fine tremor in the upper extremities, hyperreflexia (4+ patellar reflexes bilaterally), and 4 beats of inducible ankle clonus bilaterally. Which of the following is the most likely diagnosis?

Sympathomimetic toxicity

Malignant hyperthermia

Anticholinergic toxicity

Neuroleptic malignant syndrome

Serotonin syndrome— Correct Answer

Explanation:

Serotonin syndrome is a potentially life-threatening condition caused by excess central and peripheral serotonergic activity, classically characterized by the triad of neuromuscular hyperactivity (clonus, hyperreflexia, tremor), autonomic instability (hyperthermia, tachycardia, diaphoresis), and altered mental status.

The patient is taking an SSRI (sertraline) and recently initiated high-dose over-the-counter dextromethorphan, which inhibits serotonin reuptake.
The combination results in excessive serotonergic stimulation across 5-HT1A and 5-HT2A receptors.
Physical examination findings of spontaneous/inducible ocular and ankle clonus, hyperreflexia, hyperactive bowel sounds, hyperthermia, and autonomic arousal meet the Hunter Criteria for serotonin toxicity.

Case 5: Psychiatric Decision-Making Capacity & Surgical Informed Consent

A 44-year-old woman with a 15-year history of chronic schizophrenia is admitted to the surgical service with a 24-hour history of acute right lower quadrant abdominal pain, anorexia, and low-grade fever. Physical examination reveals focal tenderness, guarding, and rebound tenderness at McBurney point. Abdominal ultrasonography confirms acute non-perforated appendicitis. When the general surgeon discusses the need for laparoscopic appendectomy, the patient is calm and attentive. She accurately explains that her appendix is inflamed and that without surgery it may burst, which could cause a severe internal infection or death. She understands the procedural risks and alternatives. When asked about her schizophrenia, she states that she occasionally hears the comforting voice of her deceased grandmother whispering in her left ear, but says, 'Grandma tells me to trust the doctors and get the surgery today.' The surgical resident expresses concern that the patient's psychotic disorder precludes her from consenting. Which of the following is the most appropriate next step in management?

Defer surgical intervention until a formal hospital ethics committee review is completed

Proceed with appendectomy after obtaining the patient's own informed consent— Correct Answer

Contact the patient's next of kin to serve as surrogate decision-maker

Initiate involuntary psychiatric commitment prior to surgery

Petition the court for emergency temporary legal guardianship

Explanation:

Decision-making capacity is decision-specific and time-specific; the presence of a chronic psychotic illness or active auditory hallucinations does not automatically render a patient incapable of providing informed consent if they understand the diagnosis, risks, benefits, and consequences of their decision.

Medical decision-making capacity requires four key elements: (a) understanding the diagnosis and proposed intervention, (b) appreciating how the information applies to one's own situation, (c) reasoning through the alternatives and logical consequences, and (d) communicating a consistent choice.
The patient explicitly articulates her condition (inflamed appendix), the intervention (appendectomy), the consequences of refusal (rupture, sepsis, death), and expresses a clear, voluntary choice.
Her auditory hallucinations do not impair her reality testing regarding the surgical illness and actually align with accepting necessary care. Therefore, she possesses capacity and her informed consent is legally and ethically valid.

Core Decision Pillars for Psychiatry

High-yield decision rules for psychotic timelines, life-threatening toxidromes, and neurocognitive differentials.

1. DSM-5-TR Psychotic Disorder Timelines

Psychotic disorders are differentiated primarily by symptom duration: Brief Psychotic Disorder (1 day to < 1 month, full recovery), Schizophreniform Disorder (1 to < 6 months), and Schizophrenia (≥ 6 months with ≥ 1 month active symptoms). Schizoaffective disorder requires ≥ 2 weeks of delusions or hallucinations without major mood episodes, differentiating it from major depression with psychotic features.

2. Differentiating Life-Threatening Toxidromes

Serotonin syndrome and neuroleptic malignant syndrome (NMS) present with hyperthermia and autonomic instability, but physical examination reliably separates them. Serotonin syndrome features neuromuscular hyperreactivity (clonus, tremor, hyperreflexia) and hyperactive bowel sounds; NMS features lead-pipe muscle rigidity, hyporeflexia, and normal to absent bowel sounds.

3. Neurocognitive Differentials: DLB vs. Alzheimer vs. Parkinson

Dementia with Lewy bodies (DLB) presents with fluctuating cognition, early vivid visual hallucinations, REM sleep behavior disorder, and parkinsonism developing concurrently with or within 1 year of cognitive decline. In Parkinson disease dementia, well-established motor parkinsonism precedes cognitive decline by more than 1 year.

Frequently Asked Questions

Common questions about shelf question volume, serotonin syndrome vs NMS, and psychotic timelines.

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Diagnostic Quiz Runner

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