Major Depressive Disorder (MDD): Diagnostic Criteria, Symptom Clusters, and Evaluation

Major Depressive Disorder (MDD) is a prevalent, disabling mood disorder defined by DSM-5 criteria requiring ≥5 symptoms during a 2-week period, with at least one being (1) depressed mood or (2) anhedonia.

Diagnostic Criteria (SIGECAPS Mnemonic)

• Sleep disturbance (insomnia/hypersomnia)
• Interest loss (anhedonia) — core
• Guilt / worthlessness (excessive, inappropriate)
• Energy loss / fatigue
• Concentration difficulty / indecisiveness
• Appetite / weight change (≥5% in month)
• Psychomotor agitation or retardation (observable)
• Suicidal ideation / behavior
• Depressed mood (sad, empty, hopeless) — core (or irritable mood in youth)

Symptoms cause clinically significant distress/impairment. Not attributable to substance/medical condition. Not better explained by schizoaffective, bipolar, etc. No manic/hypomanic episode.

Specifiers

• Severity: Mild, Moderate, Severe.
• With anxious distress, mixed features, melancholic, atypical, psychotic, peripartum, seasonal pattern.

Evaluation for Sylvia (or Any Patient)

1. Clinical interview: Symptom duration, severity, functional impact, safety (suicide risk: ideation, plan, means, intent, history).
2. Standardized scales: PHQ-9 (screen/monitor), QIDS, HAM-D.
3. Medical workup: TSH, CBC, BMP, B12, folate, urine tox — rule out medical mimics (hypothyroidism, anemia, B12 deficiency, medication effects, substance use).
4. Collateral history (with consent).
5. Differential: Persistent depressive disorder, bipolar II, adjustment disorder, grief, medical illness.

Evidence-Based Treatment

• Psychotherapy: CBT, IPT, behavioral activation (first-line mild-moderate).
• Pharmacotherapy: SSRI (sertraline, escitalopram) first-line. SNRI, bupropion, mirtazapine alternatives. 4–8 weeks for effect.
• Combined: Superior for moderate-severe.
• Neuromodulation: TMS, ECT (treatment-resistant).
• Lifestyle: Exercise, sleep hygiene, social rhythm, omega-3, light therapy.

Early intervention improves prognosis. MDD is treatable — recovery is the expectation.