Differential Diagnosis in Psychiatric-
Mental Health Across the Lifespan
Practicum | Chamberlain College of
Nursing | 50 Clinical Vignette Q&A |
DSM-5-TR Focus | Verified Answers &
Rationales
**Q1.** A 24-year-old graduate student presents with a 9-
month history of persistent sadness, anhedonia, 15-pound
weight gain, hypersomnia nearly daily, feelings of
worthlessness, and poor concentration. She endorses "mood
reactivity" where she can feel temporarily better when friends
visit. She has never had a distinct period of elevated mood. Her
symptoms cause significant social impairment. The most likely
diagnosis is:
A. Major Depressive Disorder
B. Persistent Depressive Disorder (Dysthymia)
,C. Bipolar II Disorder, Depressed Episode
D. Major Depressive Disorder with Atypical Features
**Correct Answer: D**
**Rationale:** While MDD is present, the key features of mood
reactivity (brightening of mood to positive events), significant
weight gain, and hypersomnia are diagnostic specifiers for
"Atypical Features." This is not PDD due to the clear 9-month
duration (PDD requires ≥2 years in adults). No history of
hypomania rules out Bipolar II.
**Q2.** A 17-year-old male is brought in by his parents for
increasing isolation and "odd behavior" over 8 months. He has
become convinced his classmates are inserting thoughts into his
mind and laughing at him in a coded way. He reports hearing a
voice commenting on his actions when no one is present. His
academic function has declined sharply. There is no history of
fever, head trauma, or substance use. The most urgent initial
step in diagnosis is to:
A. Start risperidone for first-episode psychosis.
B. Order an EEG and MRI of the brain.
C. Rule out a substance-induced psychotic disorder.
D. Assess for prodromal schizophrenia (Attenuated Psychosis
Syndrome).
,**Correct Answer: C**
**Rationale:** In a first presentation of psychosis in an
adolescent, excluding substance-induced etiologies (e.g.,
cannabis, stimulants, hallucinogens) is a critical and urgent
diagnostic step before concluding it is a primary psychotic
disorder. While B is important, substance use is a more common
and immediately identifiable cause. A is premature prior to a
full diagnostic assessment.
**Q3.** (Select All That Apply). A 52-year-old female with a
history of Generalized Anxiety Disorder presents with 3 weeks
of depressed mood, severe anxiety, insomnia, and frequent
tearfulness. She reports these episodes have occurred 4-5 times
per year for the past several years, always in the winter months,
with full remission in spring. Which of the following diagnoses
should be considered?
A. Major Depressive Disorder, recurrent
B. Bipolar II Disorder
C. Seasonal Affective Disorder (Major Depressive Disorder with
Seasonal Pattern)
D. Premenstrual Dysphoric Disorder
E. Persistent Depressive Disorder
, **Correct Answer: A, C**
**Rationale:** The key is the clear seasonal pattern (onset and
remission at characteristic times of year) superimposed on a
recurrent major depressive course. This fits MDD, recurrent,
with Seasonal Pattern specifier (C). A is correct as the
underlying disorder. Bipolar II requires at least one hypomanic
episode, not indicated here. PMDD is linked to menstrual cycles,
not seasons. PDD involves a persistent, non-remitting depressed
mood.
**Q4.** A 7-year-old boy's teacher reports he frequently blurts
out answers, has trouble waiting his turn, and often loses his
pencils. At home, he struggles to follow multi-step instructions
for chores. However, he can focus for over an hour on video
games or building complex Lego sets. His parents note no
hyperactivity. The most appropriate next assessment step is to:
A. Diagnose ADHD, Predominantly Inattentive Presentation.
B. Rule out Autism Spectrum Disorder.
C. Assess for symptoms in multiple settings (e.g., school report)
and evaluate for alternative causes of inattention (e.g., anxiety,
learning disorder).
D. Prescribe a trial of stimulant medication.
**Correct Answer: C**