Major depressive disorder

Audience: Patients and providers
Status: Clinical guide · patient + provider
Last updated: 2026-03-09

1. Clinical overview

Major depressive disorder is a mood disorder marked by persistent depressed mood and/or loss of interest with functional impairment, recurrence risk, and a need for active safety assessment.

2. Common causes and risk factors

Multifactorial mood disorder involving biologic vulnerability and psychosocial stressors.
Medical comorbidity, substance use, and sleep disruption can worsen course.

3. Typical symptoms

Low mood/anhedonia, sleep and appetite changes, concentration issues, guilt, suicidality risk.

4. Diagnosis and evaluation

Confirm diagnosis with guideline-based history, exam, and indicated testing.
Screen for severity, complications, and high-risk comorbid conditions.
Identify social or access barriers that could affect treatment success.

5. Treatment (non-pharmacologic)

Psychotherapy (CBT/IPT), behavioral activation, sleep and social rhythm stabilization.
Safety planning and family/caregiver engagement when appropriate.

6. Treatment (pharmacologic)

Common first-line SSRIs include sertraline, escitalopram, and fluoxetine; common SNRIs include venlafaxine and duloxetine.
Bupropion, mirtazapine, trazodone, or vortioxetine may fit better when fatigue, sexual side effects, insomnia, or cognitive symptoms drive selection.
Incomplete response may require switching agents or augmentation with aripiprazole, brexpiprazole, lithium, or other specialist-guided strategies.

7. Monitoring and follow-up

PHQ-9 trend, suicidality assessment, function, side effects, adherence.

8. Practical counseling points

Give patients a clear “what to do today / when to call / when to seek urgent care” plan.
Use teach-back to confirm understanding of treatment goals and medication instructions.
Simplify regimens when possible to improve adherence and outcomes.

9. Red flags and escalation

Escalate care urgently for severe or rapidly worsening symptoms.
Reassess diagnosis if expected response does not occur within the anticipated timeline.

10. Guideline references

Note: Educational guide only; not a substitute for individualized medical care.