How should I evaluate and initially treat a patient presenting with depressed mood?

Evaluation and Initial Treatment of Depressed Mood

Begin by immediately assessing for safety concerns—specifically risk of harm to self or others, severe agitation, psychosis, or confusion—which require emergency psychiatric referral before any other evaluation. 1, 2

Step 1: Emergency Assessment

• Evaluate for suicidal ideation or risk of harm to self/others immediately—this mandates emergency psychiatric evaluation, one-to-one observation, and interventions to reduce harm risk 1, 2
• Assess for severe agitation, psychosis, or confusion (delirium), all of which warrant urgent psychiatric or medical evaluation 1, 2
• Facilitate a safe environment while arranging emergency services 1

Step 2: Rule Out Medical and Substance-Induced Causes

Before diagnosing primary depression, you must identify and treat medical conditions and substance-induced causes of depressive symptoms. 1, 2

• Treat unrelieved physical symptoms first (pain, fatigue, nausea) as these commonly cause or exacerbate depressive symptoms 1, 2
• Rule out delirium from infection, electrolyte imbalance, or other acute medical conditions 1, 2
• Evaluate for medication-induced depression (e.g., interferon, corticosteroids, beta-blockers) 1, 2
• Screen for neurological causes: stroke, traumatic brain injury, CNS infections, seizure disorders 2
• Check for metabolic/endocrine disturbances: thyroid disorders, hypoglycemia, hyponatremia, hypocalcemia 2
• Assess for substance intoxication or withdrawal states 2

A critical pitfall: Organic flat affect from neurological damage (e.g., post-stroke aprosodic speech) can mimic primary depression but requires entirely different management 2

Step 3: Systematic Depression Screening Using PHQ-9

Use a phased screening approach starting with the 2-item PHQ-9, then completing the full 9 items only if indicated. 1

Initial 2-Item Screen:

Ask about the past 2 weeks (scored 0-3 for each item):

1. Little interest or pleasure in doing things (anhedonia)
2. Feeling down, depressed, or helpless (depressed mood)

1

• If score is 0-1 on both items: No further screening needed 1
• If score is ≥2 on either item (present "more than half the days" or "nearly every day"): Complete the remaining 7 PHQ-9 items 1

Full PHQ-9 Interpretation:

• Score 1-7: Minimal symptoms—no or minimal depression, effective coping skills 1, 3
• Score 8-14: Moderate symptoms—subthreshold depressive symptoms with mild to moderate functional impairment; seek psychology/psychiatry consultation for diagnosis 1, 3
• Score 15-19: Moderate to severe symptoms—most depressive symptoms present with moderate to marked functional interference; refer to psychology/psychiatry for diagnosis and treatment 1, 3
• Score 20-27: Severe symptoms—immediate referral to psychology/psychiatry required 1, 3, 4

The recommended cutoff is ≥8 (not the traditional ≥10) based on validation studies in medical populations, providing better sensitivity. 1

Critical Consideration—Item 9 (Suicidal Ideation):

Item 9 assesses "thoughts that you would be better off dead or hurting yourself in some way." 1

• Any endorsement of this item requires careful evaluation of frequency and specificity 1
• Patients rarely endorse this item in isolation—it typically occurs with multiple other symptoms 1
• If present with high frequency or specificity, immediate emergency evaluation is required regardless of total PHQ-9 score 1, 3
• Some clinicians omit this item, but doing so artificially lowers scores and weakens predictive validity—include it in your assessment 1

The PHQ-9 has excellent validity with 88% sensitivity and 88% specificity for major depression at a cutoff of ≥10, and even better sensitivity at ≥8 4

Step 4: Assess Risk Factors and Contextual Issues

• Identify pertinent psychiatric history, prior depression episodes, family history of mood disorders 1
• Evaluate current stressors, social support, and coping mechanisms 1
• Assess for comorbid anxiety—50-60% of patients with depression have comorbid anxiety disorders, with generalized anxiety being most prevalent 1
• Determine duration of symptoms and degree of functional impairment 1

Step 5: Initial Treatment Based on Severity

For Minimal Symptoms (PHQ-9: 1-7):

• Provide education about depression and when to seek help 1
• Monitor at regular intervals 1

For Moderate Symptoms (PHQ-9: 8-14):

• Seek consultation with psychology or psychiatry for formal diagnostic assessment 1, 3
• Consider low-intensity interventions while awaiting consultation:
  • Individually guided self-help based on cognitive behavioral therapy (CBT) 1
  • Structured physical activity programs 1
  • Group-based psychosocial interventions 1
• Pharmacologic treatment may be appropriate based on consultation 1

For Moderate to Severe/Severe Symptoms (PHQ-9: ≥15):

Immediate referral to psychology and/or psychiatry for diagnosis and treatment is required. 1, 3

• High-intensity interventions delivered by licensed mental health professionals using treatment manuals that include: 1, 3
  • Cognitive behavioral therapy (CBT)
  • Behavioral activation
  • Biobehavioral strategies
  • Education and relaxation strategies
• Pharmacologic treatment is typically indicated 1
  • No specific antidepressant is superior to others—choice should be based on: 1
    • Adverse effect profiles
    • Drug-drug interaction potential
    • Prior treatment response
    • Patient preference
  • Warn patients about potential adverse effects 1

Pharmacotherapy Considerations:

• Treat comorbid anxiety by addressing depression first—this is the usual practice when both are present 1
• Use a stepped care model, escalating intensity based on treatment response 1
• Approximately 50-60% of patients will have comorbid anxiety requiring integrated management 1

Special Population Considerations

• Older adults: Depression is more difficult to detect and often presents atypically—use age-appropriate assessment approaches 1, 2
• Cognitive impairment: Tailor assessment tools for patients with learning disabilities or dementia 1, 2
• Cultural diversity: Use culturally sensitive assessments and treatments when possible 1, 2

Ongoing Monitoring

• Reassess PHQ-9 scores regularly to track treatment response 3
• Screen at regular intervals during treatment, at 3,6, and 12 months post-treatment, at disease recurrence/progression, and during personal transitions 1
• Provide education to patients and families about warning signs that warrant immediate contact with providers 1

Common Pitfalls to Avoid

• Never assume flat affect is primary depression—always rule out neurological causes like stroke or organic brain syndromes 2
• Don't skip the medical rule-out—treating unrelieved physical symptoms often resolves or improves depressive symptoms 1, 2
• Don't underestimate PHQ-9 scores of 15 or higher—these represent significant clinical depression requiring professional intervention 3
• Don't omit Item 9 assessment—suicidal ideation requires specific evaluation and management 1
• Don't delay referral for moderate to severe depression—these patients need specialist evaluation and high-intensity interventions 1, 3