Major Depressive Disorder

Overview

Major Depressive Disorder (MDD) is a serious mood disorder characterized by persistent feelings of sadness, hopelessness, and loss of interest in activities. It affects approximately 280 million people worldwide.

Diagnostic Criteria (DSM-5)

≥5 of the following for ≥2 weeks, including at least one of the first two:

1. Depressed mood most of the day
2. Anhedonia — diminished interest or pleasure
3. Significant weight change (>5% in a month)
4. Insomnia or hypersomnia
5. Psychomotor agitation or retardation
6. Fatigue or loss of energy
7. Feelings of worthlessness or guilt
8. Difficulty concentrating
9. Recurrent thoughts of death or suicidality

Treatment Options

Risk Factors

• Genetics — 2-3x risk with first-degree relative
• Trauma — Childhood adversity, abuse
• Medical — Chronic illness, hormonal changes
• Social — Isolation, poverty, relationship problems

MDD is a leading cause of disability worldwide. Early treatment significantly improves outcomes, with 60-70% of patients responding to first-line therapy.