Major Depressive Disorder (MDD) is one of the most common psychiatric conditions worldwide, affecting approximately 280 million people globally. This article provides a comprehensive overview of MDD for medical professionals and students.
DIAGNOSTIC CRITERIA
According to DSM-5, MDD requires five or more of the following symptoms present during the same 2-week period, with at least one being depressed mood or loss of interest/pleasure:
1. Depressed mood most of the day, nearly every day
2. Markedly diminished interest or pleasure in all or almost all activities
3. Significant weight loss or gain, or decrease/increase in appetite
4. Insomnia or hypersomnia nearly every day
5. Psychomotor agitation or retardation
6. Fatigue or loss of energy nearly every day
7. Feelings of worthlessness or excessive guilt
8. Diminished ability to think or concentrate
9. Recurrent thoughts of death or suicidal ideation
EPIDEMIOLOGY
The lifetime prevalence of MDD is approximately 15-20%, with women affected twice as often as men. Peak onset typically occurs in the mid-20s, though depression can develop at any age.
TREATMENT APPROACHES
Firstline treatments include
Pharmacotherapy
- SSRIs (sertraline, fluoxetine, escitalopram)
- SNRIs (venlafaxine, duloxetine)
- Bupropion
- Mirtazapine
Psychotherapy
- Cognitive Behavioral Therapy (CBT)
- Interpersonal Therapy (IPT)
- Behavioral Activation
For treatmentresistant cases, consider
- Augmentation strategies (lithium, atypical antipsychotics)
- Electroconvulsive Therapy (ECT)
- Ketamine/esketamine
- Transcranial Magnetic Stimulation (TMS)
PROGNOSIS
With appropriate treatment, 60-70% of patients respond to first-line therapy. Early intervention and maintenance treatment significantly reduce recurrence risk.