Psychopathopharmacology 1 MSN 671 quiz 3

Correct Answer:

A. Homicidal impulses

Explanation:

This presentation is classic for phencyclidine (PCP) intoxication. Key features include violent behavior, psychosis (hallucinations, depersonalization), severe hypertension, tachycardia, nystagmus (especially vertical or rotary), ataxia, dysarthria, and muscle rigidity. PCP intoxication is notorious for producing impulsive violence, agitation, and homicidal impulses.

Why Other Options Are Wrong:

B. Increased appetite

This is incorrect because increased appetite is characteristic of cannabis intoxication, not PCP.

C. Nosebleed

This is incorrect because nosebleeds are more commonly associated with intranasal cocaine use, not PCP.

D. Decreased respiratory rate

This is incorrect because decreased respiratory drive is seen in opioid intoxication (eg, heroin, morphine, fentanyl), not PCP. PCP usually causes hyperactivity and autonomic stimulation.

Correct Answer:

A. Dopamine in the prefrontal cortex

Explanation:

Volume neurotransmission refers to neurotransmitter release that is not restricted to the synaptic cleft but instead diffuses over a wider area, influencing multiple neurons. In the prefrontal cortex, dopamine terminals often lack classic synaptic specializations. Instead, dopamine is released into the extracellular space, where it diffuses and binds to receptors located away from release sites. This is a prime example of volume transmission.

Why Other Options Are Wrong:

B. Dopamine in the striatum

This is incorrect because dopamine release in the striatum occurs primarily at well-defined synaptic junctions with precise wiring, making it a clear case of wired transmission rather than volume transmission.

C. Norepinephrine in the prefrontal cortex

This is incorrect because norepinephrine in the prefrontal cortex can have modulatory effects, but it is dopamine that is specifically recognized in the literature as the classic example of volume transmission in this region.

D. Norepinephrine in the striatum

This is incorrect because norepinephrine projections to the striatum are sparse, and where present, they do not serve as the hallmark example of volume transmission.

Correct Answer:

A. Ketamine

Explanation:

Ketamine, an NMDA receptor antagonist originally used as an anesthetic, has been found effective in treating treatment-resistant depression and rapidly reducing suicidal thoughts. Unlike traditional antidepressants that may take weeks to work, ketamine produces effects within hours. It is often administered intravenously in specialized clinics, and a related formulation, esketamine (Spravato®), is FDA-approved as a nasal spray for treatment-resistant depression.

Why Other Options Are Wrong:

B. Propofol

This is incorrect because propofol is an intravenous anesthetic used for induction and maintenance of anesthesia. It is not used in psychiatric treatment for depression or suicidality.

C. Hydroxyzine

This is incorrect because hydroxyzine is an antihistamine with sedative and anxiolytic properties. It may reduce anxiety but is not indicated for resistant depression or suicidal ideation.

D. Valium

This is incorrect because Valium (diazepam) is a benzodiazepine used for anxiety, muscle spasms, and seizures. It does not treat depression or suicidal thoughts and carries risks of dependence.

Correct Answer:

C. Benign Neutropenia

Explanation:

Clozapine carries a risk of agranulocytosis, so prescribers monitor the absolute neutrophil count (ANC) before and during treatment. Some African American patients may have benign ethnic neutropenia (BEN) — a genetic variation leading to lower baseline neutrophil counts without an increased risk of infection. This can hinder initiation of clozapine because standard ANC cutoffs may falsely exclude these patients. Adjusted guidelines now allow for BEN, but prescribers must be aware of this factor before ruling out clozapine.

Why Other Options Are Wrong:

A. Low plasma dimension

This is incorrect because there is no recognized genetic factor called "low plasma dimension" influencing clozapine use.

B. Low Seizure Threshold

This is incorrect because clozapine does lower the seizure threshold at high doses, but this effect is not a specific genetic factor tied to African Americans.

D. None

This is incorrect because benign neutropenia is a real genetic factor in African Americans that impacts clozapine initiation.

Correct Answer:

B. Resensitization of nicotinic receptors

Explanation:

Nicotine binds to nicotinic acetylcholine receptors (nAChRs) in the brain, causing receptor activation and dopamine release, which produces reinforcement. After nicotine exposure, nAChRs become desensitized and stop responding despite nicotine being present. Over time (about every 1–2 hours), the receptors resensitize, becoming responsive again. This resensitization drives craving and withdrawal because the brain seeks nicotine to re-activate the now-sensitive receptors, creating the cycle of dependence.

Why Other Options Are Wrong:

A. Desensitization of nicotinic receptors

This is incorrect because desensitization occurs right after smoking, not when cravings emerge. Cravings arise when receptors resensitize.

C. Desensitization of muscarinic receptors

This is incorrect because muscarinic acetylcholine receptors are not the primary target of nicotine in addiction. Nicotine acts on nicotinic receptors, not muscarinic ones.

D. Resensitization of muscarinic receptors

This is incorrect because muscarinic receptors are not central to nicotine craving and withdrawal. The addiction mechanism involves nicotinic receptor cycles, not muscarinic receptor activity.

Correct Answer:

B. Glutamate and glycine

Explanation:

NMDA receptors are a subtype of glutamate receptors that require co-activation by two ligands: glutamate (the main excitatory neurotransmitter) and glycine (or D-serine, acting as a co-agonist). Once both bind, the receptor channel can open, but only if the magnesium block is relieved by depolarization.

Why Other Options Are Wrong:

A. Glutamate only

This is incorrect because glutamate alone cannot open NMDA receptors; the co-agonist glycine (or D-serine) is also required.

C. Glutamate, glycine, and magnesium

This is incorrect because magnesium actually blocks the NMDA receptor channel at resting potential. For the channel to function, magnesium must be displaced by depolarization, not bound.

D. Glutamate and magnesium

This is incorrect because magnesium is not required for activation; instead, it is an inhibitor at resting membrane potential.

Correct Answer:

A. Han Chinese and HLA-B*15:02

Explanation:

Han Chinese individuals have a significantly increased risk of developing Stevens-Johnson Syndrome (SJS) or toxic epidermal necrolysis (TEN) when treated with carbamazepine if they carry the HLA-B*15:02 allele. This allele is strongly associated with severe cutaneous adverse reactions to carbamazepine, and screening is recommended before initiating therapy in populations with high prevalence, such as Han Chinese, Thai, and other Southeast Asian groups.

Why Other Options Are Wrong:

B. African American and HLA-B15:02

This is incorrect because while African Americans may carry other HLA risk alleles, **HLA-B15:02 is rare in this population**, making the risk much lower than in Han Chinese or Southeast Asians.

C. White American and HLA-B15:02

This is incorrect because the prevalence of **HLA-B15:02 in White Americans is extremely low**, so carbamazepine-induced SJS/TEN is not strongly linked to this allele in this population.

D. Hispanic American and HLA-B15:02

This is incorrect because Hispanic populations also have a low frequency of HLA-B15:02, so the genetic risk is not comparable to Han Chinese or other Asian groups.

Correct Answer:

A. Benzodiazepines

Explanation:

Benzodiazepines are well known to act on ionotropic receptors, specifically the GABA-A receptor, which is a chloride ion channel. By binding allosterically, benzodiazepines increase the frequency of chloride channel opening in response to GABA, leading to enhanced inhibitory signaling. This ionotropic mechanism allows benzodiazepines to take immediate clinical effects, such as sedation, anxiolysis, or anticonvulsant action, compared to drugs that act via slower metabotropic pathways.

Why Other Options Are Wrong:

B. Ionic compounds

This is incorrect because "ionic compounds" is not a drug class in psychopharmacology. It is a chemistry term referring to substances made of ions, not medications that act on receptors.

C. Antipsychotic

This is incorrect because most antipsychotics act on metabotropic G-protein-coupled receptors (GPCRs), such as dopamine D2 or serotonin 5-HT2A receptors. Their effects are slower and not mediated through ionotropic channels.

D. Antidepressants

This is incorrect because antidepressants, including SSRIs, SNRIs, and TCAs, primarily act by blocking neurotransmitter reuptake or influencing GPCR-mediated systems. They do not exert their main actions at ionotropic receptors and therefore do not produce immediate effects.

Correct Answer:

A. Olanzapine

Explanation:

Cigarette smoke (polycyclic aromatic hydrocarbons) induces CYP1A2, increasing the clearance of drugs that are CYP1A2 substrates. Olanzapine is primarily metabolized by CYP1A2 (with minor roles for UGT and CYP2D6), so smokers often have lower serum levels and reduced efficacy, frequently requiring higher doses compared with non-smokers. When patients start or stop smoking, olanzapine doses often need adjustment to maintain therapeutic effect and avoid side effects.

Why Other Options Are Wrong:

B. Lamotrigine

Incorrect. Lamotrigine is cleared mainly by UGT1A4 glucuronidation, not CYP1A2. Smoking does not meaningfully reduce lamotrigine effectiveness via CYP induction.

C. Fluphenazine

Incorrect. Fluphenazine is metabolized largely by CYP2D6 (and some CYP3A4). While smoking can have modest effects on various pathways, it’s not a CYP1A2 substrate of clinical concern like olanzapine (or clozapine).

D. Benztropine

Incorrect. Benztropine is not primarily metabolized by CYP1A2, and smoking is not known to significantly reduce its effectiveness through this mechanism.