Major Depressive Disorder

Psychiatry

≥2 weeks of depressed mood or anhedonia + ≥4 SIGECAPS symptoms causing impairment (DSM-5).

Clinical features

  • Low mood, anhedonia
  • Sleep / appetite / weight change
  • Fatigue, ↓concentration
  • Guilt, hopelessness
  • Suicidal ideation

Investigations

  • PHQ-9
  • Risk assessment
  • Exclude organic: TFT, B12, glucose

Diagnosis

  • DSM-5 / ICD-11 criteria

Differential diagnosis

  • Bipolar depression
  • Adjustment disorder
  • Hypothyroidism
  • Substance-induced
  • Dementia (pseudodementia)

Management

  • Mild: guided self-help, CBT
  • Moderate–severe: SSRI + CBT
  • Severe / treatment-resistant: ECT, augmentation

Drug therapy

  • Sertraline 50 mg OD (start)
  • Mirtazapine 15 mg nocte if insomnia/weight loss
  • Avoid stopping abruptly — discontinuation syndrome

Complications

  • Suicide
  • Functional decline
  • Substance misuse

Clinical pearls

  • Reassess at 2 weeks, full response at 6–8 weeks
  • Always assess suicide risk + collateral history

Educational — verify locally.

WardRound

WardRound

Clinical Decisions in Seconds