13 USMLE Psychiatry, Toxicology and Ethics Quick Review Questions with Answers (Set 1)

These 13 quick USMLE review questions test high-yield facts that show up again and again on the exam: Hawthorne effect, relative risk, HIV screening, medication adherence, discharge of intoxicated patients, interpreters, congenital CMV, PCP, Wernicke-Korsakoff, Tourette syndrome, aspirin and cocaine. Each question includes the correct answer.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. Which of the following factors most likely affects the result of a study due to awareness of study subjects that they are being studied?

A- Berkson’s bias
B- Hawthorne effect
C- Pygmalion effect
D- Recall bias

B- Hawthorne effect- It is an error due to informing the study subjects about the it so, their personal preference will negatively affect the study results.
The correct answer is B

 

Question 2. A study found that the incidence of lung cancer in smokers is 230/100,000 and in non-smokers is 71/100,000. What is the relative risk for smokers?

A- 2.3
B- 3.2
C- 71
D- 230

B- 3.2- Relative risk is reached by dividing the smokers’ group by the non-smokers’.
The correct answer is B

 

Question 3. According to CDC recommendations, who should be screened for HIV at least once?

A- All persons aged 13 to 64 years
B- Only men who have sex with men
C- Only patients with symptoms of AIDS
D- Only blood and semen donors

A- All persons aged 13 to 64 years- The CDC recommends opt-out HIV screening at least once for everyone aged 13 to 64, regardless of risk. People at higher risk (for example men who have sex with men, people with multiple partners or who inject drugs) should be tested at least once a year. All pregnant women, patients with symptoms, partners of HIV-positive people, and blood and semen donors must also be tested.
The correct answer is A

 

Question 4. A 63-year-old woman visits her physician for a follow-up after a week of antibiotic therapy for acute bronchitis. Her condition has deteriorated. Her physician suggested repeating the antibiotic. The patient disagreed, saying that she does not like to take the antibiotic, and she did not take it as prescribed. Which of the following is the appropriate response?

A- Do you understand the benefits of taking this medication on time?
B- I am afraid you have to take this antibiotic; otherwise, you will have more complications of the condition.
C- Why don’t you like to take this medication?
D- What side effects did you experience?

C- Why don’t you like to take this medication?- The most appropriate response is to check for the cause of not taking this specific medication. Sometimes, it happen to be the reason is big capsule that hard to swallow or bad taste..etc..
The correct answer is C

 

Question 5. A 30-year-old man is brought to the emergency room for alcohol intoxication. His blood alcohol level is 250 mg/dL. He refused to take any medications and insisted on leaving the hospital. What is the most appropriate response to this patient?

A- We cannot release you before you become sober
B- We will call the police if you don’t take treatment
C- You can leave anytime if you want
D- You have to sign consent to leave

A- We cannot release you before you become sober- The patient is considered incompetent to make a decision so, it is inappropriate to release him even with consent. Calling police is appropriate only in case of hitting staff or destroying property which is not mentioned here.
The correct answer is A

 

Question 6. A 12-year-old girl is brought to the emergency room with her parents. Consent from the parents is needed to proceed with the treatment. The parents speak Spanish and very little English. What is the best next step of action?

A- Find any Spanish-speaking person in the clinic to interpret the instructions
B- Speak to the boy to find out if he speaks English, and if he does, explain the instructions to him.
C- Try your best to explain the treatment plan to them
D- Use an electronic interpreting device to translate the instructions

D- Use electronic interpreting device to translate the instructions- They need to know exactly the instructions before they sign the consent.
The correct answer is D

 

Question 7. Which of the following conditions is characterized by the presence of periventricular calcified densities on brain imaging?

A- Cytomegalovirus infection
B- Down syndrome
C- Huntington’s disease
D- Toxoplasmosis

A- Cytomegalovirus infection- Calcification only occurs in CMV and toxoplasmosis but they are scattered in the cortex in toxoplasmosis.
The correct answer is A

 

Question 8. A college student is brought to the ER for fever and agitation. Examination reveals high temperature, tachycardia, constricted pupils and horizontal nystagmus. Which of the following is the responsible substance?

A- Alcohol
B- Cocaine
C- Lysergic acid diethylamide
D- Phencyclidine

D- Phencyclidine- It is the only one that presents with agitation and the above eye manifestations.
The correct answer is D

 

Question 9. Amnestic syndrome due to thiamine deficiency is caused by lesions of which one of the following structures?

A- Cerebellum
B- Limbic system
C- Parietal lobe
D- Temporal lobe

B- Limbic system- Amnestic syndrome occurs due to lesions of the limbic system.
The correct answer is B

 

Question 10. A young boy presents with echolalia, frequent eye blinking, repetitive frowning and head shaking to the left. These movements subside when he answers the questions or clears his throat. Which of the following is the most likely diagnosis?

A- Epilepsy
B- Huntington disease
C- Parkinsonism
D- Tourette syndrome

D- Tourette syndrome- Echolalia is repetition of another person’s words in a meaningless way. Tic disorder is characterized by echolalia and other movements mentioned in this scenario.
The correct answer is D

 

Question 11. A child is brought to the emergency room after ingestion of a full bottle of medication two hours ago. The child is in a coma with tachypnea, tachycardia, and metabolic acidosis. Which of the following is the responsible medication?

A- Acetaminophen
B- Aspirin
C- Hydrocodone
D- Vitamin C

B- Aspirin- Is the only medication on the list that causes a mixture of respiratory alkalosis (tachypnea) and metabolic acidosis.
The correct answer is B

 

Question 12. A 25-year-old man is brought by the police for screaming and attacking neighbors. His temperature is 102.4 F, his respiratory rate is 30/min, his pulse is 110/min, his blood pressure is 170/90 and his pupils are dilated. He suddenly becomes unresponsive and requires resuscitation. Which of the following substances is most likely to have been taken?

A- Cocaine
B- Ethanol
C- Heroin
D- Morphine

A- Cocaine- This is the only drug of the list causing this clinical picture esp. dilated pupils.
The correct answer is A

 

Question 13. Which of the following is the most dangerous adverse effect of chronic alcohol abuse?

A- Cutaneous vasodilation
B- Impaired judgment
C- Liver cirrhosis
D- Respiratory depression

C- Liver cirrhosis- It occurs gradually due to chronic alcohol abuse. Other options are acute side effects of alcohol.
The correct answer is C

 

High-yield points from this set

  • Hawthorne effect: people change behavior because they know they are being studied.
  • Screen everyone aged 13–64 for HIV at least once.
  • Always use a professional interpreter, not family members.
  • Periventricular calcifications = congenital CMV; diffuse calcifications = toxoplasmosis.

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