In our first PMHNP Difficult Cases article, we introduced one of the simplest yet most effective clinical tools available: the ABC approach (Antecedent, Behavior, Consequence). That framework remains timeless because it teaches us to understand behavior before trying to change it. More importantly, it teaches us to think before we prescribe.
Today we're building on that idea.
Today is about learning to recognize when the psychiatric diagnosis may not explain the entire patient.
One of the best pieces of advice I ever received was this:
☕ Paper doesn't refuse ink.
Medical records accumulate over years. Diagnoses get copied forward. Medication lists become outdated. Symptoms are documented without context. Sometimes the chart is really accurate. Sometimes it contains assumptions that have never been questioned.
One of the defining characteristics of an experienced PMHNP is learning which pieces of information deserve confidence, which deserve skepticism, and which deserve further investigation.
Let's walk through a case.
PART 1
The Chart
Educational info: Everything below represents the information available before you enter the exam room.
Referring Provider: Licensed Mental Health Therapist
Reason for Referral
Client has participated consistently in psychotherapy for the past three months with limited improvement in depressive symptoms. Continues to report low mood, fatigue, poor motivation, and impaired concentration despite appropriate therapeutic engagement. Request psychiatric evaluation for diagnostic clarification and medication management.
Chief Complaint
"My wife said if I don't get help, she's leaving."
History of Present Illness
44-year-old married male presents for an initial psychiatric evaluation following referral from his therapist.
The patient reports worsening depressive symptoms over approximately five months.
Symptoms include:
Depressed mood
Fatigue
Poor motivation
Difficulty concentrating
Insomnia
Decreased appetite
Approximately 8-pound unintentional weight loss over several months
Reports consuming approximately 4-6 alcoholic beverages most evenings, stating alcohol helps "shut my brain off."
Denies suicidal ideation.
Denies history of mania or psychosis.
Psychosocial History
Married for 12 years.
Employed full-time.
Reports increasing marital conflict related to mood symptoms and alcohol use.
Currently engaged in weekly outpatient psychotherapy.
Past Psychiatric History
Diagnoses
Major Depressive Disorder
Alcohol Use Disorder
Previous Medication Trials
Escitalopram
Sertraline
Psychiatric Hospitalizations
None
Past Medical History
Type 2 Diabetes Mellitus
Hypertension
GERD
Current Medications
Sertraline 150 mg daily
Trazodone 50 mg nightly
Metformin
Lisinopril
Omeprazole
Review of Systems
Constitutional
Fatigue
Decreased appetite
Mild weight loss
Gastrointestinal
Chronic intermittent diarrhea
Psychiatric
Depressed mood
Poor concentration
Insomnia
Mental Status Examination
Appearance: Casually dressed, appropriately groomed, appears stated age.
Behavior: Cooperative
Speech: Normal rate and volume
Mood:
"Depressed."
Affect: Constricted
Thought Process: Linear
Thought Content: No suicidal or homicidal ideation. No psychosis.
Insight: Fair
Judgment: Fair
PHQ-9: 20
Physical Examination
BP: 128/76
HR: 84
BMI: 25
General appearance: No acute distress.
Available Medical Records
The patient provides laboratory results obtained after his annual primary care visit approximately one month ago.
Test | Result |
Hemoglobin | 11.1 g/dL |
Hematocrit | 35% |
RBC | 3.48 M/µL |
MCV | 104 fL |
WBC | 6.4 ×10⁹/L |
Platelets | 140 ×10⁹/L |
Indirect Bili | 1.5 mg/dl |
STOP
Before Reading Further...
Imagine this patient sitting in your office.
Take a moment and formulate the case.
What is your working diagnosis?
What additional questions would you ask?
What belongs in your differential?
What is your initial treatment plan?
Then continue.
PART 2
Clinical Commentary
How the Novice PMHNP Thinks
Educational Commentary: This section is not part of the patient's chart. It illustrates a common reasoning pattern early in practice.
Problem Representation
"This is a patient with severe Major Depressive Disorder and Alcohol Use Disorder."
Information That Receives the Greatest Weight
✔ PHQ-9 = 20
✔ Existing diagnosis of MDD
✔ Patient reports depression
✔ Wife threatening separation
Information skipped over
Elevated MCV
Mild anemia
Chronic diarrhea
Appetite change
Weight loss
Assessment
Major Depressive Disorder
Alcohol Use Disorder
Plan
Increase sertraline.
Continue trazodone.
Recommend psychotherapy.
Encourage alcohol reduction.
Follow-up in four weeks.
Notice what happened.
The psychiatric diagnosis became the explanation for every symptom.
The laboratory findings were acknowledged but never incorporated into the case formulation.
PART 3
Clinical Commentary
How the Experienced PMHNP Thinks
Educational Commentary: Again, this section is not part of the patient's chart. It illustrates one example of expert clinical reasoning.
The experienced PMHNP starts with a different question.
Instead of asking: "How do I treat depression?"
They ask: "What diagnosis best explains the entire patient presentation?"
Immediately several findings deserve attention:
Daily alcohol use
Elevated MCV, Elevated Indirect Bilirubin, Decreased PLT
Mild anemia
Chronic diarrhea
Fatigue (new)
Appetite change (new)
Weight loss (new)
None of these findings individually establishes a diagnosis.
Together, however, they suggest that depression may not be the entire story.
Revised Problem Representation
"A 44-year-old male with depressive symptoms occurring in the setting of significant alcohol use, gastrointestinal complaints, and hematologic abnormalities requiring evaluation for both primary psychiatric illness and possible medical contributors."
Notice something interesting.
The experienced PMHNP hasn't diagnosed vitamin B12 deficiency.
They haven't diagnosed celiac disease.
They haven't diagnosed liver disease.
They've simply avoided premature closure.
Expanded Differential
Psychiatric
Major Depressive Disorder
Alcohol-Induced Depressive Disorder
Potential Medical Contributors
Alcohol-related nutritional deficiency
Vitamin B12 deficiency
Folate deficiency
Hypothyroidism
Liver disease
Malabsorption syndrome
Sleep disorder
Medication effects
Other endocrine or metabolic disorders
PART 4
Assessment & Plan
Educational Commentary: The documentation below is fictional and intended to demonstrate one example of concise clinical reasoning, documentation, and interdisciplinary collaboration. SI has been ruled out.
Assessment
44-year-old male with a history of Major Depressive Disorder and Alcohol Use Disorder presenting a complex constellation of depressive and systemic symptoms.
Today's presentation is also notable for daily alcohol use, elevated MCV with mild anemia, chronic intermittent diarrhea, fatigue, appetite changes, and recent weight loss. PHQ-9 = 20. These findings raise concern for possible medical and substance-related contributors to his psychiatric presentation.
While the patient meets criteria for a depressive episode, the overall presentation appears multifactorial. Although antidepressant dose escalation remains a reasonable future option, the presence of multiple potential medical contributors supports completing additional medical evaluation before making further pharmacologic changes.
Plan
Major Depressive Disorder
Continue sertraline 150 mg daily through shared decision-making.
Continue weekly psychotherapy.
Reassess medication strategy after additional medical information is available or sooner if symptoms worsen.
Alcohol Use Disorder
Reviewed the relationship between alcohol use, mood, sleep, and antidepressant response. Utilized motivational interviewing to assess readiness for change. Discussed treatment options and advised against abrupt alcohol cessation without medical supervision.
Medical Evaluation
Reviewed CBC abnormalities and associated symptoms with the patient. Recommended prompt follow-up with his PCP for evaluation of possible medical contributors to the current presentation.
Care Coordination
Discussed the benefits of collaborating with the PCP. (Patient agreed to complete a Release of Information (ROI). Upon receipt, a focused summary of today's clinical concerns and recommendation for further medical evaluation will be communicated to the PCP).
Follow-Up
Return in 3 weeks or sooner for worsening symptoms. Reassess diagnosis and treatment recommendations as additional medical information becomes available.
🍵 Tea Pairing
Some patients don't fit inside a neat guideline.
The patient in today's case reminds us that medicine isn't practiced one diagnosis at a time. Depression, alcohol use, unexplained weight loss, diarrhea, anemia, elevated MCV…no algorithm tells you exactly what to do next. That's where clinical judgment matters.
If you enjoy working through complex cases like this, the Advanced Clinical Pharmacology Conference from PESI is worth a look. Rather than reviewing medications in isolation, it focuses on the real-world decisions clinicians face every day.
Across 23 expert-led sessions, you'll work through layered case scenarios covering women's health, obesity, anxiety, sleep, infectious disease, abdominal complaints, and much more. The emphasis is on building a practical decision-making framework you can apply in clinic the very next day.
You'll earn up to 40.25 CE hours (including up to 27.0 pharmacology hours) and can attend live or watch on demand.
Eva's Tea readers: Use code PHARMA100 to register for $199.99.
Affiliate Disclosure: Eva's Tea is a PESI affiliate. If you register through the link below, I may earn a small commission at no additional cost to you. I only feature educational resources that I believe provide value to psychiatric and primary care clinicians.
☕ Final Teaching Point
Notice what the experienced PMHNP didn't do.
Ignore the abnormal CBC.
Assume every symptom was caused by depression.
Increase medication simply because the PHQ-9 was 20.
Order a broad medical workup outside the purpose of the consultation.
Automatically send the psychiatric note to another provider.
Anchor on the therapist's referral diagnosis.
Instead, they recognized a pattern, broadened the differential, documented why the findings mattered, involved the patient in shared decision-making, coordinated appropriately with the PCP, and allowed the evolving clinical picture (not a screening score to guide treatment decisions).
The novice PMHNP asks:
"What is the psychiatric diagnosis?"
The experienced PMHNP asks:
"What information am I still missing before I change treatment?"
That difference changes everything.
Because paper doesn't refuse ink.
☕ Eva's Tea Takeaway
The best PMHNPs don't rush through details.
They pause, question the story the chart is telling, and make sure the diagnosis explains the patient, not just the symptoms.
Selected References
Torrez, M., Chabot-Richards, D., Babu, D., Lockhart, E., & Foucar, K. (2022). How I investigate acquired megaloblastic anemia. International Journal of Laboratory Hematology, 44(2), 236–247. [1]
Hesdorffer, C. S., & Longo, D. L. (2015). Drug-induced megaloblastic anemia. The New England Journal of Medicine, 373(17), 1649–1658. [2]
Sanvisens, A., Zuluaga, P., Pineda, M., Fuster, D., Bolao, F., Tor, J., Muga, R., & the Investigators of the Cohort of Addiction Patients in General Hospital. (2017). Folate deficiency in patients seeking treatment of alcohol use disorder. Drug and Alcohol Dependence, 180, 417–422. [3]
Lindenbaum, J., & Roman, M. J. (1980). Nutritional anemia in alcoholism. The American Journal of Clinical Nutrition, 33(12), 2727–2735. [4]
Díaz, L. A., König, D., Weber, S., Lévesque, E., Bataller, R., Arab, J. P., & Thursz, M. (2025). Management of alcohol use disorder: A gastroenterology and hepatology-focused perspective. The Lancet Gastroenterology & Hepatology, 10(5), 456–470. [5]