Psychopathology and Diagnostic Reasoning | Walden
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Section 1: Foundations of Psychopathology & Neurobiology (Q1-15)
Q1. A 28-year-old patient presents with persistent low mood, anhedonia, and fatigue.
Neuroimaging reveals decreased metabolic activity in the dorsolateral prefrontal cortex
(DLPFC) and increased activity in the subgenual anterior cingulate cortex (sgACC).
Which neurotransmitter system is most directly implicated in the pathophysiology of
these findings?
A. Dopaminergic mesolimbic pathway
B. Serotonergic raphe-cortical projections [CORRECT]
C. Noradrenergic locus coeruleus projections
D. Cholinergic basal forebrain projections
Rationale: The DLPFC hypometabolism and sgACC hyperactivity pattern is
characteristic of major depressive disorder and is directly linked to serotonergic
dysfunction, particularly involving projections from the dorsal raphe nucleus. SSRIs
normalize sgACC activity. Option A is more relevant to schizophrenia and reward
pathways. Option C is more relevant to arousal and anxiety. Option D is more relevant to
neurocognitive disorders.
Correct Answer: B
Q2. A PMHNP is evaluating a patient with chronic stress who reports weight gain, sleep
disturbance, and impaired concentration. Laboratory studies reveal elevated evening
,cortisol levels and flattened diurnal cortisol slope. Which component of the HPA axis is
most likely dysregulated in this presentation?
A. Anterior pituitary corticotroph hyperresponsiveness to CRH
B. Hippocampal glucocorticoid receptor downregulation leading to impaired negative
feedback [CORRECT]
C. Hypothalamic CRH deficiency
D. Adrenal zona fasciculata atrophy
Rationale: Chronic stress causes hippocampal glucocorticoid receptor downregulation,
impairing negative feedback on the HPA axis and resulting in elevated cortisol and
flattened diurnal slope. Option A describes acute stress response. Option C would
cause cortisol deficiency. Option D contradicts the elevated cortisol finding.
Correct Answer: B
Q3. A 35-year-old patient with treatment-resistant depression is being considered for
ketamine therapy. The PMHNP explains that ketamine's rapid antidepressant effect is
primarily mediated through which mechanism?
A. Direct agonism of mu-opioid receptors
B. Blockade of NMDA glutamate receptors with subsequent AMPA receptor activation
and BDNF release [CORRECT]
C. Inhibition of monoamine oxidase enzymes
D. Blockade of serotonin reuptake transporters
Rationale: Ketamine is a non-competitive NMDA receptor antagonist. Its rapid
antidepressant effect occurs via AMPA receptor activation, increased BDNF release, and
synaptogenesis in the prefrontal cortex. Option A describes opioid analgesia. Option C
describes MAOIs. Option D describes SSRIs.
Correct Answer: B
,Q4. A patient with schizophrenia shows minimal response to first-generation
antipsychotics but improves significantly with clozapine. This clinical pattern most
strongly suggests dysfunction in which receptor system?
A. D2 receptor hypersensitivity alone
B. Combined D2/5-HT2A imbalance with relative preservation of mesocortical D1
function [CORRECT]
C. Pure GABA-A receptor deficiency
D. Excessive nicotinic acetylcholine receptor activity
Rationale: Clozapine's efficacy in treatment-resistant schizophrenia suggests
involvement of serotonin-dopamine imbalance (5-HT2A antagonism) and mesocortical
D1 modulation, beyond simple D2 blockade. Option A explains typical antipsychotic
response, not clozapine-specific efficacy. Options C and D are not primary mechanisms
in schizophrenia psychopathology.
Correct Answer: B
Q5. A PMHNP is reviewing the role of epigenetics in psychopathology. Which statement
best describes how early-life adversity can produce lasting changes in gene expression
without altering DNA sequence?
A. Through direct mutation of glucocorticoid receptor genes
B. Via DNA methylation of promoter regions and histone modification affecting
chromatin structure [CORRECT]
C. By inducing permanent chromosomal translocations
D. Through amplification of mitochondrial DNA copy number
Rationale: Epigenetic mechanisms include DNA methylation (typically silencing gene
expression) and histone modifications (acetylation, methylation) that alter chromatin
accessibility without changing DNA sequence. Early adversity increases methylation of
, the NR3C1 gene (glucocorticoid receptor). Option A describes genetic mutation, not
epigenetics. Options C and D are not primary epigenetic mechanisms.
Correct Answer: B
Q6. A patient with panic disorder demonstrates exaggerated fear responses to
conditioned stimuli even after extinction training. Functional neuroimaging shows
hyperactivation of the amygdala and diminished activity in which regulatory structure?
A. Dorsal striatum
B. Ventromedial prefrontal cortex (vmPFC) [CORRECT]
C. Primary motor cortex
D. Cerebellar vermis
Rationale: The vmPFC normally exerts top-down inhibition on the amygdala during fear
extinction. Diminished vmPFC activity is implicated in panic disorder and PTSD, where
extinction learning is impaired. Option A is involved in habit formation. Option C is not
involved in fear regulation. Option D is involved in coordination, not emotional
regulation.
Correct Answer: B
Q7. A 42-year-old patient with bipolar I disorder is stabilized on lithium. The PMHNP
explains that lithium's mood-stabilizing effects are partly mediated through inhibition of
which intracellular signaling pathway?
A. cAMP-PKA pathway
B. Phosphoinositide (PI) signaling and glycogen synthase kinase-3 (GSK-3) inhibition
[CORRECT]
C. Nitric oxide-cGMP pathway
D. JAK-STAT cytokine signaling pathway