Neurobiology of addiction — MCQs

A 32-year-old man is brought to the emergency department because he was found stumbling in the street heedless of oncoming traffic. On arrival, he is found to be sluggish and has slow and sometimes incoherent speech. He is also drowsy and falls asleep several times during questioning. Chart review shows that he has previously been admitted after getting a severe cut during a bar fight. Otherwise, he is known to be intermittently homeless and has poorly managed diabetes. Serum testing reveals the presence of a substance that increases the duration of opening for an important channel. Which of the following symptoms may be seen if the most likely substance in this patient is abruptly discontinued?

A genetic population study is being conducted to find the penetrance of a certain disease. This disease is associated with impaired iron metabolism and primarily affects the liver. Patients often present with diabetes and bronze skin pigmentation. After a genetic screening of 120 inhabitants with a family history of this disease, 40 were found to have the disease-producing genotype, but only 10 presented with symptoms. What are the chances of the screened patients with said genotype developing the disease phenotype?

A 49-year-old woman presents to the clinic for a routine exam. She recently quit smoking after a 30 pack-year history and started exercising a little. Past medical history is noncontributory. She takes no medication. Her mother died at 65 from lung cancer. She rarely drinks alcohol and only uses nicotine gum as needed. She admits to having some cravings for a cigarette in the morning before work, and after work. Which of the following best describes this patient’s stage in overcoming her nicotine addiction?

A 42-year-old man is brought in to the emergency department by his daughter. She reports that her father drank heavily for the last 16 years, but he stopped 4 days ago after he decided to quit drinking on his birthday. She also reports that he has been talking about seeing cats running in his room since this morning, although there were no cats. There is no history of any known medical problems or any other substance use. On physical examination, his temperature is 38.4ºC (101.2ºF), heart rate is 116/min, blood pressure is 160/94 mm Hg, and respiratory rate is 22/min. He is severely agitated and is not oriented to his name, time, or place. On physical examination, profuse perspiration and tremors are present. Which of the following best describes the pathophysiologic mechanism underlying his condition?

A 40-year-old man is brought to the emergency department after sustaining multiple lacerations during a bar fight. The patient’s wife says that he has been showing worsening aggression and has been involved in a lot of arguments and fights for the past 2 years. The patient has no significant past medical or psychiatric history and currently takes no medications. The patient cannot provide any relevant family history since he was adopted as an infant. His vitals are within normal limits. On physical examination, the patient looks apathetic and grimaces repeatedly. Suddenly, his arms start to swing by his side in an uncontrolled manner. Which area of the brain is most likely affected in this patient?

A 22-year-old man is brought to the physician by his mother because of concerns about his recent behavior. Three months ago, the patient first reported hearing loud voices coming from the ceiling of his room. During this time, he has also become increasingly worried that visitors to the house were placing secret surveillance cameras. Mental status examination shows tangential speech with paranoid thoughts. Treatment for this patient's condition predominantly targets which of the following dopaminergic pathways?

A neuroscientist is delivering a lecture on the electrophysiology of the brain. He talks about neuroreceptors which act as ion channels in the neurons. He mentions a specific receptor, which is both voltage-gated and ligand-gated ion channel. Which of the following receptors is most likely to be the one mentioned by the neuroscientist?

A 19-year-old man presents to a psychiatrist for the management of substance abuse. He reports that he started using the substance 2 years ago and that he smokes it after sprinkling it on his cigarette. He describes that after smoking the substance, he feels excited and as if he does not belong to himself. He also reports that when he is in his room, he sees vivid colors on the walls after using the substance; if he listens to his favorite music, he clearly sees colors and shapes in front of his eyes. There is no history of alcohol or nicotine abuse. The psychiatrist goes through his medical records and notes that he had presented with acute substance intoxication 1 month prior. At that point, his clinical features included delusions, amnesia, generalized erythema of his skin, tachycardia, hypertension, dilated pupils, dysarthria, and ataxia. Which of the following signs is also most likely to have been present on physical examination while the man was intoxicated with the substance?

A 30-year-old man presents to his family physician admitting to using heroin. He says he started using about 6-months ago when his back pain medication ran out. At first, he says he would borrow his wife’s Percocet but, eventually, that ran out and he had to find a different source. Since then, he has been having more and more issues related to his heroin use, and it has started to affect his work and home life. He is concerned that, if he continues like this, he might end up in real trouble. He denies sharing needles and is sincerely interested in quitting. He recalls trying to quit last month but recounts how horrible the withdrawal symptoms were. Because of this and the strong cravings, he relapsed shortly after his initial attempt. Methadone maintenance therapy is prescribed. Which of the following would most likely be the most important benefit of this new treatment plan in this patient?

A 68-year-old man, accompanied by his wife, presents to his physician with cognitive decline and hallucinations. The patient’s wife tells that his cognitive impairment progressed gradually over the past 6 years, and first began with problems counting and attention. The hallucinations began approximately a year ago. The patient describes them as realistic and non-frightening; most often, he sees his cat accompanying him everywhere he goes. The patient’s wife also notes frequent episodes of staring spells in her husband and prolonged daytime napping. The blood pressure is 130/80 mm Hg with the orthostatic change to 110/60 mm Hg, heart rate is 75/min, respiratory rate is 13/min, and the temperature is 36.6°C (97.8°F). The patient is alert and responsive, but he is disoriented to time and place. He is pale and hypomimic. The cardiac, lung, and abdominal examinations are within normal limits for the patient’s age. The neurological examination is significant for a bilateral symmetrical cogwheel rigidity in the upper extremities. What would you most likely see on additional radiological investigations?