Clues Pointing TO This Diagnosis

Pervasive low mood over about six months with a sustained ≥2-week episode — depressed mood most of the day, nearly every day is a core diagnostic criterion
Loss of interest/pleasure, including abandoning reading that she had always loved — anhedonia is the second core symptom and one of the two required "gateway" criteria
Hypersomnia (sleeping about twelve hours) — sleep disturbance (insomnia or hypersomnia) is a diagnostic symptom
Loss of appetite/food "losing its flavor" — appetite change is a recognized neurovegetative symptom
Fatigue and getting up for work only out of obligation — loss of energy nearly every day supports the diagnosis
Impaired concentration — diminished ability to think or concentrate is a criterion symptom
Neglect of self-care (not showering for several days) and social withdrawal (stopped answering the phone) — reflects clinically significant functional impairment required for diagnosis
Passive death wishes without a plan or intent — recurrent thoughts of death/passive suicidal ideation is a diagnostic symptom and mandates a safety assessment
PHQ-9 score of 19 — corresponds to moderately severe depression and supports active treatment
Progressive, functionally disabling course prompting evaluation — the symptoms cause distress/impairment and are not better explained by another condition

Why It's NOT the Similar Diseases

NOT bipolar disorder — there is no history of manic or hypomanic episodes; major depressive disorder requires the absence of prior mania/hypomania, and screening for bipolarity is essential before starting an antidepressant
NOT persistent depressive disorder (dysthymia) — Norma has a discrete episode over months with severe neurovegetative symptoms rather than chronic low-grade depressed mood lasting ≥2 years
NOT normal grief/adjustment reaction — there is no described precipitating loss, and the number, severity, and duration of symptoms with functional collapse meet full criteria for a major depressive episode
NOT a depressive disorder due to another medical condition — nothing in the history attributes her symptoms to a medical illness or substance, a required exclusion (Criterion C)
NOT substance/medication-induced depression — no substance use is described, so the episode is not attributable to a substance's physiologic effects

Differential Diagnosis List

Bipolar disorder — ruled out by absence of any prior manic or hypomanic episode
Persistent depressive disorder (dysthymia) — ruled out by the acute severe episodic course rather than ≥2 years of chronic low mood
Normal bereavement/adjustment disorder — ruled out by full symptom count, severity, and marked functional impairment
Depression due to a general medical condition (e.g., hypothyroidism, anemia) — ruled out by absence of an attributable medical illness on history
Substance/medication-induced mood disorder — ruled out by absence of substance use

Key Distinguishing Test

Major depressive disorder is a clinical diagnosis based on DSM-5-TR criteria—at least five of nine symptoms for ≥2 weeks, including depressed mood or anhedonia, with functional impairment and exclusion of substance/medical causes.
A standardized severity tool such as the PHQ-9 supports diagnosis and tracks response; a score ≥10 identifies probable major depression (sensitivity and specificity ~85%), and Norma's score of 19 indicates moderately severe depression.
Every positive screen requires assessment of suicide risk, bipolar disorder, and psychotic symptoms.

Board Note

Screen with the PHQ-2/PHQ-9; a PHQ-9 ≥10 suggests major depression and severity bands are 5–9 mild, 10–14 moderate, 15–19 moderately severe, 20–27 severe
Before treating, assess for suicidality (PHQ-9 item 9), bipolar disorder, and psychosis, since these change management and may require specialty referral
First-line treatment is psychotherapy (e.g., CBT) or a second-generation antidepressant (SSRI/SNRI); for moderate-to-severe or chronic depression, combined medication plus psychotherapy is often preferred
Counsel that antidepressants may take 2 weeks to begin working and 6–12 weeks for full effect; monitor closely early and reassess if inadequate response by ~6–8 weeks
After remission, continue antidepressants at least 6 months; for recurrent or high-risk disease, continue ≥2 years or longer to prevent relapse
Refer/escalate for active suicidality, psychotic or catatonic features, suspected bipolar disorder, or treatment resistance; ECT is indicated for severe depression with psychosis, catatonia, severe suicidality, need for rapid response, or a prior good ECT response
The following figure from the 2024 JAMA review maps first-line treatment recommendations to PHQ-9 severity across major guideline bodies, illustrating why a patient at Norma's severity is offered medication and/or psychotherapy:
Figure 1. Evidence-Based Guideline Recommendations for Initial First-Line Treatment of Depression According to Severity
Management of Depression in Adults: A Review. JAMA. July 8, 2024.
Content used under license from the JAMA Network®
© American Medical Association

“Norma’s Story”